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Modafinil and Startups (swombat.com)
217 points by anthony_franco on Feb 27, 2012 | hide | past | web | favorite | 127 comments

It's worth noting that not everyone responds to modafinil. If you've had genetic sequencing done (I had mine done by 23andme), you can predict your response by checking your Rs4680 status. http://www.snpedia.com/index.php/Rs4680

  rs4680(G;G) carriers deprived of sleep respond quite well to 2x 100mg
  modafinil in terms of improved vigor and well-being, and maintained
  baseline performance with respect to executive functioning, whereas
  rs4680(A;A) individuals barely responded to the drug at all.
I'm A;A, and normally have almost no response to modafinil. I discovered, however, that I have significant modafinil response while on an MAOI (transdermal selegiline). I've stopped taking it recently, since I've finally tracked down the primary causes of my excessive sleepiness, (very deficient in vitamin D and cortisol). Modafinil has been a massive help both with fatigue and depression, and let me stay functional and productive through a difficult time in my life while I tracked down the actual problems.

Contrary to what some doctors tell you, it is really hard to fix a Vitamin D deficiency with dietary supplements. Go to a tanning salon and get 250,000IUs in 10 minutes. Of course this is going to be a bit weird if you are naturally dark skinned, but far more effective than taking pills.

Citation? I ask because I'm interested in making sure I'm healthy, not to just be a jerk on the internet, and if that's true I'm doing something wrong.

Steve Gibson is digging into Vitamin D:


No citations exist. My comment was directed at the grandparent whose original symptoms warranted taking dangerous MAOIs. In that case, I would consider an off literature treatment to fix the vitamin D deficiency as fast as possible. Tanning beds are carcinogenic and not recommended for general health.

I started taking MAOIs while trying to deal with depression. SSRIs had pretty severe cognitive side-effects for me, and low doses of transdermal MAOIs have a better risk profile than traditional oral MAOIs. You're right about dangerous, though. I first started modafinil while on the MAOI, and didn't find out that it didn't work for me off of it until I stopped using the MAOI due to apparent serotonin toxicity, which you don't want to screw around with.

Oral vitamin D is not taken up by the body all that well. If you do have a D deficiency and you're taking oral supplements, be sure to get your levels checked after 6 months. You may need to up your dose or get some direct sunlight.

For me at least, this is certainly true. Even with significant dietary supplements and spending more time outside, I've only been able to get up to about 25 ng/mL. This is a significant improvement for me, as my initial levels were below the sensitivity of the test, at <0.25 ng/mL, but still not ideal. I hadn't considered visiting a tanning salon; I may try that soon if things aren't notably improved after the next time I get this tested.

I'm A;G - anyone know what that might mean? Any idea why that genotype wasn't in the study?

Deficient in cortisol? That sounds very interesting... Isn't that the stress hormone? What kind of effects was that having on your life, other than the sleepiness?

Specifically, cortisol normally has a significant peak in the morning with waking, but I don't have that. My cortisol levels throughout the day are about flat, so normal for the evening, but not elevated in the morning. According to my doctor, this isn't too unusual, and should adjust up to normal levels after some months of supplementation. I just started supplements two weeks ago, and I'm definitely far more awake during the day and have a much easier time starting the day, but I haven't noticed any other significant changes, so I don't know anything else attributable to this. The only other changes I've noticed have been pretty minor, like an easier time exercising, and maybe a bit more irritable.

Chiming in: cortisol IS "the stress hormone" but "stress" in the body sense is not the same thing as we think of "stress" in our daily lives.

With my chronic fatigue syndrome, there was a period where I had signs of "adrenal fatigue." My body would not produce sufficient cortisol and it REALLY showed. Symptoms included difficulty with physical activity, e.g. standing up or climbing stairs, an overwhelming agoraphobic-in-a-mosh-pit feeling in my head when faced with making any kind of decision, weighing facts, or even too much sensory input (e.g. talking to me while touching me or touching me while I tried to tie my shoes), etc. I would jerk away and have a sobbing meltdown because I couldn't cope. Among people with adrenal/cortisol issues, that is called a "crash".

So I have learned that sensory input, thinking, information processing, etc., are all types of stress on the system. Cortisol is required for the body and brain to "rise to the challenge" of almost every kind of effort, not just "I'm freaking out" type stress. In the case of the OP, staying awake was clearly a challenge his body could not rise to because it had insufficient cortisol on hand.

    What I found with more experimentation of days both with
    and without Modafinil was that actually, I was just as
    productive if I was well rested, healthy, well fed with
    healthy foods and working on something I cared about.
This, I think, is the most interesting part of the entire piece. He talks at length about the benefits of Modafinil:

    On the good side, those tasks which I did line up got
    done, and with great energy, velocity, etc. A good day
    on Modafinil could easily concentrate several days'
    worth of work into one, by getting rid of all the empty
    distracted bits of the day."
(which sound fantastic) but then mentions that you can get the same benefits just by being healthy. Makes me think that it's kind of incredible what our body can do on its own.

I was just as productive if I was well rested, healthy, well fed with healthy foods and working on something I cared about.

Those are four conditions that are difficult to fulfill 24/7. I'd go so far as to say that it's difficult to have a normal social life and always be well-rested and fueled with healthy foods. Case in point: I have a dance class on Wednesday nights that breaks up after ten o'clock. No way I'm sleeping until 1am or 2am on those nights. But I exercise in the mornings, so I can't stay up until 1am or 2am every night. My life is an engineering exercise, and like any engineering exercise, there are a lot of compromises. I'm curious about using Modafinil judiciously to make up the gap once in a while, possibly at the once-per-few-months frequency he says would be okay. It's incredible what our body will do -- virtually anybody can run a marathon, for example -- but it takes a lot of orchestration to convince our body to release its miserly grip on our resources and do the job we'd like it to do.

That is my own main takeaway... Which is why I don't take Modafinil anymore.

Coincidentally, I'm about to go off to college, where I'm sure I'll be sorely tempted by "intelligence enhancers" like Modafinil. Even in my high school there is rampant abuse of Adderall and other stimulants. Thanks for the timely discussion of their effects - although I'm not predisposed towards taking them, I've now got some good information on why there's no need to do so.

in my high school there is rampant abuse of Adderall and other stimulants

Recreationally, or for study?


What about combining good health with using Modafinil? The naive idea is if they are good by themselves, they could be better together.

When I'm well rested, well fed, healthy, etc, then the Modafinil just has the basic effect of increasing focus and energy while decreasing breadth of thinking, with the comedown 8 or so hours later that leaves me sucked dry. It's not that bad, but it's not so great as to be worth the risk on a regular basis, imho.

Did you post this once before? The entire article and especially the conclusion/takeaway sounds so very familiar! (but the publication date is today)

Nope, but I did post some of this in some hn comments before...

It must have been a combination of those comments and this previously-posted article (also on the same drug):


Taking a pill, however, is much easier than keeping a proper diet and sleep schedule and working only on what you like...

And no matter how awesome your project, there will be times that you must push through the muck.

It is incredible what the body can do on its own. On the other hand, it's a little disappointing that the body can do this under normal circumstances, but society today pushes it to a false sense of efficiency, and people start taking performance-enhancing medications to get back to the ability we already have.

The conditions aren't mutually exclusive. You can be "healthy, well fed with healthy foods", exercise, and still use modafinil to counteract lack of sleep. I completely agree that eating properly and exercising (or not) will have a huge impact on productivity but they do not make up for sleep.

I threw my last pack away last year, due to the emergence of a nasty side effect. I'd used it to power through a few insane projects, and had what I would call a decent "honeymoon period": get up at 4am, brain so groggy it was hard to tie my shoelaces, pop 100mg and within 30 minutes I'd be hyper-awake, clear headed and have laser sharp focus. The euphoria he mentions was nothing mild for me either, it really wasn't far off something like cocaine or ecstacy (minus accompanying loss of faculty).

Then gradually another feeling started accompanying it, which I can only describe as a "darkening" of my perception of the world, and strong sense of impending doom which became intrusive and hard to ignore (to the detriment of whatever task was at hand). It rendered me mildly depressed and highly anxious at the same time (although only for about 12-14 hours), and it did so consistently. I've never heard anyone else mention such an effect, but if anyone starts feeling a bit like that (and for me it was frankly a powerful and rather scary side-effect), consider whether the drug is to blame.

This is exactly what I felt when I was taking Adderall when I was about 25. I chose to stop taking it after a few months because I just couldn't handle the sense of impending doom, and at times fear, which would strike every day around 7pm.

I've had a very similar negative reaction at times in waves maybe an hour long, though the general sense of doom tended to condense into very specific ideas: the sort of thoughts you might find when watching a horror movie, except applied to real life and impossible to ignore. As a result, despite having a legitimate prescription, I'm very sparing in my use.

I don't get the euphoria and I avoid using it while seriously sleep deprived - I despise the feeling of my physical body needing sleep. For reference, aside from caffeine and alcohol, it's the only (mind-altering) drug I've ever taken, so it's not due to interactions outside that sphere.

I've read a few other stories similar to yours but it seems quite rare. They seemed to be from past recreational drug users who said the same thing about it acting similarly to cocaine. It would be an interesting avenue of research. I wonder if it's related to past cocaine use or if both drugs act on the same receptors certain individuals have higher levels of.

I didn't get around to trying Modafinil, but I've discovered that pure caffeine and guarana extract work better than coffee for me. I was a heavy coffee drinker all my life, but several years ago, it just stopped working as well. There's something in coffee besides caffeine that makes me feel jittery and nervous without feeling more alert after a couple of days of drinking it regularly. Basically, it helps with physically intensive tasks, but doesn't help when I have to sit down and do any kind of mental work anymore.

Using 100 mg of caffeine 3x a day, on the other hand, gives me the same effect as coffee once did - I can jump around filled with energy and work at my computer with more energy for longer periods of time. 400 mg of guarana extract (~80 mg caffeine) makes me more alert without the physical tension or jitters - if anyone has "coffee fatigue", as I call it, try caffeine pills or guarana extract (but not in high dosages!).

I've also found L-carnitine to augment caffeine in physical tasks, and taking 400mg of guarana extract with ~200mg of rhodiola rosea and 50mg of L-theanine lets me work and then sleep pretty well, like I never took caffeine in the first place. YMMV, but it's definitely fascinating to see how we can alter our bodies with psychoactives (obviously, you take a risk, so you have to understand that and doing proper research before using anything).

I still want to try Modafinil, but just can't get my hands on it right now...

Is it just me, or does using mind-altering substances to get through one's daily schedule seem like it crosses the line?

I'm always a little baffled when people sacrifice their health for work - it's a very bad decision in the long term. You can always find another job, but once you damage your health, you may never get it back.

There are plenty of mind altering substances in our diet. I eagerly await the day we can culturally accept that alcohol is an archaic drug, and we can replace it with modern alternatives that don't destroy livers and families.

Modafinil could already be a modern alternative to coffee. It's definitely not perfect, but in some ways it's a lot better and it seems to be safe enough. It's far from perfect - for example I'm in the 10% who get headaches from it, so I prefer not to use it. But when a better alternative comes... I can't wait to replace caffeine.

We had a great replacement for caffeine -- ephedrine. Mini-Thins were a staple of my college life. Then they banned it (I blame media hysteria), and now I'm stuck with the steeping ephedra plant leaves (known as "Mormon tea" in these parts) for the occasional late-night productivity boost.

My understanding is that ephedrine was one of very few drugs that had a demonstrated ability to increase metabolism and decrease hunger, at least when combined with caffeine[1]. It did so in relative safety, and the only deaths I'm aware of were due to overdose. Given the obesity problem in the US, I'm still amazed that it got banned.

[1] http://www.ncbi.nlm.nih.gov/pubmed/1318281

Try Bronkaid.

Whether this drug does damage your health in the long run is no where near determined.

I think, more interestingly, I'd ask if it were to become known that modafinil (or adderall) were harmful long term, would people still use it to gain competitive advantage. If we gain a nootropic with significant effects, at what point does it become disadvantageous not to jump on the mystery train? The 'line' that can be crossed is different for everyone.

Everything you put in your body is a mind-altering substance. Food, coffee, beer, etc all provide different chemicals to your brain. I used to have a similar mindset to yours. I didn't use caffeine and didn't even like taking something for headaches.

When I looked at it from another perspective I changed my mind. It's irrational to not take something if the benefits exceed costs. If you can take something, with benefits that outweigh the side effects, why wouldn't you? Everything has costs and benefits. Of course most people will underestimate risk and overestimate benefits so you have to do this carefully.

Caffeine is a perfect example. When taken in proper dosage caffeine is beneficial with almost no side effects. The biggest side effect is addiction which isn't much of a problem with its availability and is easy to overcome.

Doesn't seem like that to me... Taking psychoactives is like a shortcut if you don't want to (or more likely just can't!) do it the hard way (with willpower alone). Besides, there are people who smoke and drink and still live longer than their "health-freak" peers - I still find that interesting and somewhat unfair.

Also, using caffeine pills instead of coffee and recommending them to others leads to wide eyes and "you take drugs?" kind of questions - apparently, that is crossing the line, yet drinking two huge mugs of coffee in a row isn't. Human psychology, go figure :-)...

Do you drink coffee or caffeinated soda? Also Modafinil by itself doesn't seem to cause any health problems, so I'm not sure what you're getting at there. The impure Adrafinil can cause liver problems though. I'd agree that a drug that gave work benefits but resulted in brain damage 2 years later isn't worth it, but let's be specific when talking about what health risks are around for particular chemicals, diets, and chairs/no chairs.

My own experience with Modafinil is that it lets me focus intently on one or a handful of things for longer periods of time, but doesn't give me much if any boost in willpower to pick, so I rely on putting myself in the right environment where there's only a few options to pick from.

> Do you drink coffee or caffeinated soda?

In fact, I don't, and precisely for this reason. Caffeine addictions seem to be just as bad to me.

Instead, I sleep more (enough so I don't have to use an alarm) and strive to cut unnecessary things from my life to save time. For example, I know it's a little cliche, but people survived without TV until 50 or 60 years ago. I got rid of my TV, and it saved me a lot of time.

Do you eat sugary foods? Fatty foods? Ingesting sugar and fat causes your brain to release dopamine. Without this mind-altering biochemistry, people wouldn't be nearly as compelled to eat a piece of a chocolate cake or a piece of bacon.

(Note: dopamine reabsorption is also slowed by caffeine, which is why it improves your mood.)

My point is not to be pedantic, it's to say that no matter what you're ingesting, you're altering your mood. While I'd obviously agree that becoming addicted to mood-altering substances isn't a good thing, I think that (like sugar and fat) they can be used responsibly.

> The impure Adrafinil can cause liver problems though.

Adrafinil always needs disclaimers, but looks like it is now a thing of the past with Olmifon shutting down production.

Err, nope, coffee is pretty popular.

The differences between coffee and modafinil are: coffee tastes better, modafinil does the same job for longer with less side effects.

Popularity is a poor way to judge whether or not something is good for you. If you went back in time 60 years and asked someone whether inhaling large quantities of carcinogenic gases was a bad idea, they'd say "Err, nope, cigarettes are pretty popular" too.

I think that his point was that you wouldn't walk around the office pointing at everyone with a cup of coffee and saying "that crosses the line".

In reply to your original comment - for work you don't care about, I'd agree with you, but plenty of people who do stuff like this, particularly I assume when it comes to HN readers, really do care about their work. For example there's plenty of times I'll work more hours than I technically have to because I want to, and so if I were to take drugs to help that, it wouldn't neccesarily be a case of "get a new job". Incidentally I do smoke, because I enjoy it more than I care about the health risks right now.

Actually, modafinil is practically tasteless, which I would say is objectively better than the bitter taste of coffee. Of course, it's possible to train yourself to enjoy that bitter taste through operant conditioning, but it's not really a "better" taste.

Or you could drink tea, which is tasty, and then you also get both caffeine and theanine.

Except that tea tastes terrible, and adding creamer and saccharine doesn't improve it as much as it does coffee. ;)

Creamer? You must be some sort of godforsaken English tea drinker - if you have good green or oolong tea, you don't need to adulterate it with anything.

Do you consume sugar, vitamins or oxygen? Have you ever inhaled Nitrogen Oxide or maybe stood near a car while its engine was on? Nevermind. This concern of long term health is reducible to: what effect does taking this action have on my probability of living for X more years at present functioning or better. Notice that merely being alive negatively impacts this, while when you are alive positively impacts the odds. Being sedentary and sitting for most of your day affects the probability very negatively. Is sitting most of your day worse for you than taking modafinil daily? I suspect being sedentary is far worse for you.

Or another, we can compare the effects of modafinil with getting into a car on a similar basis. With some basic knowledge of brain chemistry, claimed effects of the drug, understanding of placebo effect (~occurs in 1 in 3 or consider: drug OR Expectation/placebo Inferior to Drug AND Expectation), the drug's statistics, poor methodology in medical statistics and years of drug availability you can form a decent prior.

Based on my prior, taking modafinil is certainly not more lethal or less healthy than getting in a car and being near its fumes. So fear of health effects without any reasonable basis are not a rational argument to me. The supposed strong adverse effects? This is an argument for more understanding of how metabolisms and bodies differ, I have a confirmed strong allergy to nuts for example. Peanuts are much more dangerous to me than modafinil.

Yet I do not take modafinil. Not based on some unsubstantiated reverence for default biochemistry but instead on reasoned arguments. Its effects seem like they would impact creative thinking negatively. Furthermore, it is expensive and does not appear to have superior effects beyond being less addictive, a smoother delivery and a safer high dose cardiovascular profile than caffeine [1]. That is, modafinil does not appear to be any better at keeping you awake or focused than caffeine.

Similarly, I do not take caffeine because of its dependency forming nature and while it appears to boost working memory, enough studies indicate it antagonizes hippocampal function [2] to motivate me to minimize caffeine intake to every few weeks or less, as necessary. The mechanisms for modafinil are different so we can't expect all effects to be the same as caffeine. But it too seems to effect some improvement in working memory - most noticeable when the individual is lower performing [3] but according to [4] modafinil does show some negative effects on long term memory processes situated at the prefrontal cortex. in rats. Remember though, just because something appears in a medical journal doesn't make it true or accurate, especially when done on animal models or cell cultures. Nonetheless, the benefits in contrast with monetary costs and minute risks make modafinil not worth it and caffeine a very irregular thing for me.

Notice that I am not attacking your reluctance to take modafinil but rather, your opinion seems to be based on a nebulous definition of what a drug is and an assumption that the brain's architecture is optimal and any attempt to alter it will definitely be negative.

See also - Sulbutiamine. A vitamin B1 dimer.

[1] http://www.ncbi.nlm.nih.gov/pubmed/11862356

[2] http://www.ncbi.nlm.nih.gov/pubmed/19217915

[3] http://www.ncbi.nlm.nih.gov/pubmed/15221200

[4] http://www.ncbi.nlm.nih.gov/pubmed/20800665

I've found it occasionally helpful, but it will in no way fix procrastination -- in fact you can procrastinate (by e.g. reading through top 100 random stories on reddit) more efficiently and with fewer regrets. If you can get into the "flow" (in the psychological sense) you're able to stay there for longer and are less likely to get interrupted, but you're better off starting the day with a clear todo list and by priming things by producing, not consume (as per the recent articles).

If mixing with coffee, consume both well before you intend to sleep; I've found myself a few times in an unpleasant alert but wanting to sleep state.

> I've found it occasionally helpful, but it will in no way fix procrastination -- in fact you can procrastinate (by e.g. reading through top 100 random stories on reddit)

In my (ahem) friends experiments with modafinil he reported the same thing, i.e. that he procrastinated with a vengeance. Last time this happened he managed to get through O'Reilly's _Mastering Algorithms in C_ in a single sitting, though it was completely unrelated to the work he was supposed to do that day.

I got as far as having some really intensely focused world of warcraft sessions on modafinil... What a waste...

Not only that, but modafinil is also great when you absolutely, positively, have to win a flame war on the Internet.

I have taken 100-400mg of Modafinil daily for about 10 years.

I happen to have my 23andme results (thanks for the tip, tene!) and it looks like I'm rs4680(A;A). Despite what the paper in CPT says, it does have a significant effect on my alertness.

The comments about procrastination and focus all sound familiar to me. So do the comments about addiction: sometimes I'll forget to take it and if I don't have any because I forget to pack it while travelling I don't feel an urge to do anything about it. I only have a few things to add to what's been said already:

1) Modafinil is not a substitute for sleep for me. I've gone without sleep for days while using it, and I do suffer from the effects of sleep deprivation. I just don't notice that I'm suffering from them. The best way to describe it is that I am alert and thinking, but I am missing half my IQ points and don't realize it unless I'm particularly mindful about how I am feeling. I'm great at driving, working out, the boring parts of reverse engineering firmware, and other mindless repetitive physical tasks, though. A few years ago I decided to spend a lot of time at the gym and was performing at superhuman levels: it's just not normal for a 5'8" guy to feel happy about running 6 minute miles at 4 AM on no sleep. When I did that on no sleep I kept losing my keys and phone, though...

2) Modafinil significantly increases my ability to get out of bed in the morning. I've never taken a sick day since I started using it. If I don't get enough sleep I still zone out a little during the day, but it makes it so much more pleasant to get out of bed and go through my morning routine if I'm missing sleep. I'm certainly in better shape because I have the energy to go work out, as I mentioned.

3) I'm quickly approaching the point where I'll have been on Modafinil for more than 50% of my life, and as far as I can tell there have been no long-term side effects. My partner is a MD and although at first she couldn't believe that it wasn't permanently screwing something up, she's come to accept that Modafinil seems to be pretty safe in my case.

4) Despite what others have said about Modafinil affecting their creative thinking, I have no problems assimilating entirely new concepts or doing other abstract thinking while using the drug.

> Despite what the paper in CPT says, it does have a significant effect on my alertness.

You're not the first 23andMe user I've heard say that; as I caution people in my section on the topic ( http://www.gwern.net/Modafinil#effects ) SNP studies are pretty gosh-darn unreliable, and even if the SNP effect turns out to be genuine (as they often do not), the effect may not be worth caring about.

Gwern has a summary article[1] on Modafinil which (among other things) goes through the literature on the effects and side-effects.

[1]: http://www.gwern.net/Modafinil

I've commented on Modafinil before ( http://news.ycombinator.com/item?id=647333 ). Please see caveats there.

I would say that Modafinil does not make a boring task interesting. It does not supply any drive to work.

I characterise the effects as blowing away that fog you sometimes feel is within your head.

Even better, I have found that it is quite possible to sleep on Modafinil. It will be light sleep because if you're indulging then you probably have a lot on your mind anyway and this will dictate how well you sleep.

You'll find that you wake up with some residual effect ( clarity ). This is a good thing, unlike a hangover/comedown.

Hm, didn't expect to see this on Hacker News. Better copy over my comment from Reddit http://www.reddit.com/r/Nootropics/comments/q878x/modafinil_... :

> Sure, you won't find studies of people who fried their neurons by using Modafinil for 10 years in a row, but that's because Modafinil isn't that old yet.

Actually, it is. Even ignoring all the animal and French experiments etc, Cephalon got FDA approval and started selling it in the US in... 1997? 1998? That's close to 14 years now.

This is why blogs with no comments annoy me - how is the author supposed to find out that he made an obvious mistake? Or for that matter his claim modafinil is more amphetamine-like that proponents claim - well, I'm a proponent but at least when I claim it has little in common, I have [actual citations](http://www.gwern.net/Modafinil#fn11).

EDIT: I checked; it was approved in December 1998, so 1 December 1998 - today is 13 years, 2 months, and 27 days.

> This is why blogs with no comments annoy me - how is the author supposed to find out that he made an obvious mistake?

Email? His site-wide byline is a mailto.

Yes, so I can email him and hope he will update or edit or admit he's wrong, and also accept that by the time he does so most readers will be gone - rather than post a public comment he would specifically have to censor, and my correction be visible in time for most readers to see if they care to.

I hope you can see why I would regard one alternative as way better than the other.

Proving my point: a day later, with the comment on both Hacker News & Reddit, his incorrect claim remains. In fact, as far as I can tell, he has not edited it at all.

Why, again, would I prefer to email him?

Interesting. I take modafinil 2-ish times a week, sometimes to skip a night's sleep to work on my own projects, sometimes to get a really productive day at my day-job with a startup.

My subjective experience with driving on Modafinil is very different: I become significantly more aware of everything on the road. It turns me into a laser, sure, but a laser that's constantly scanning back and forth. Too many confounding factors to say why that is.

I haven't noticed any diminishing of 'broad thinking'. Not sure I could claim any increase, though.

His claim that it's better to get productive days through other means seems to be a false dichotomy: Modafinil isn't dangerous like he's convinced it is, and while you can get productive through better health and rest, you can get even more productive by eating healthy, exercising, resting properly, and taking Modafinil. It's not clear why he thinks that Modafinil will force you to be unhealthy, thus making it a choice between "healthy" and "moda" (Honestly, the days when I take Modafinil, I find I have the focus to exercise harder and longer, and the willpower to eat much healthier).

His points about 'shortcut to a really productive day', 'having a clear big task to focus on', and 'drink a lot of water' are all spot-on, though.

I have to disagree with his recommendations: I think Modafinil's value proposition is positive for almost everyone, and proportionally more valuable as the value of your time or focus increases. HN readers in particular tend to have valuable time and extremely valuable focus; Modafinil is a huge gain, something like a large fraction of just the positives of amphetamines, with the negatives of caffeine instead.

The illustrious gwern has an article covering the medical research, benefits, risks, a novel cost/benefit analysis, and supplier information here: http://www.gwern.net/Modafinil

(Yes, it's been linked a few times already in this discussion. Go read it already.)

The thing I find most interesting about Modafinil is how consistent the stories are about how people feel (and work) when they take it.

Everyone talks of extreme focus, but perhaps a loss of judgement about what tasks are actually important.

I don't have any particular conclusions about that - I just find it really interesting.

This is an excellent tl;dr for what it does. I had some truly excellent Minecraft sessions, for instance..

I've read a lot about modafinil and I think your observations are selection bias. It may improve focus more than caffeine but not like amphetamines or other drugs used to treat ADHD. Judgement may be impaired when taking any stimulant. If it's something you're aware of it's not hard to work around.

I've heard a fair number of people report getting no effect, and recall reading somewhere that there's a gene which separates modafinil responders from non-responders. It's just that non-responders tend not to talk about it, since it's much less interesting in that case.

I've taken it a few times when I really had to push hard to meet a deadline (coding). One time while working my sister texted me to say she just boarded her flight to Canada (from Europe). What seemed like a short while after she texted me saying she'd arrived. During her entire flight (6+ hrs) my concentration never flinched. I find it very effective indeed.

I have taken 200mg of Modafinil daily for more than 5 years.

Before it, I could go to sleep just about anywhere and just about any time. I could easily sleep for 12 to 14 hours a day if I let myself. When I had a work commute of about an hour and a half, I would have to pull over, sometimes four or five times, during the afternoon drive home to take cat naps because I couldn't keep my eyes open. It didn't matter how much or how little coffee I drank, it didn't matter how much I slept the day before, and it didn't matter whether I was eating my typical diet which was fairly healthy, or if I had unusual amounts of junk food that week.

Caffeine doesn't work "normally" for me. I like the taste of coffee, I usually have one cup a day that I sip throughout the morning. However, I don't have a Folgers moment. I am not groggy until I get my first cup. If I drink a soda or coffee or even have a shot of espresso in the afternoon, I don't get a sudden boost of energy. I don't even get the boost of energy from energy drinks. When I drink a lot caffeine or other energy drinks in a short period of time, I find that they will give me a mild case of the jitters, but even then, they don't counteract my actual drowsiness. Hence, I've never gone higher than my typical cup of coffee in the morning and frequently a soda in the afternoon. More than that has almost all down-sides and no up-sides for me.

I took a sleep study, and I was not diagnosed with narcolepsy because that diagnosis is very specific. You must immediately fall into REM sleep. I was diagnosed with a "we have no idea what you have" condition of excessive daytime drowsiness and received a prescription for Provigil. Originally, it was a 100mg dose, but when that was not effective, it went up to 200mg.

It is a bit of a wonder drug for me, but certainly not in the terms that it was described in this article. It doesn't make me hyper focused or give me unusually sharp focus, it just removes the incapacitating drowsiness I suffered in the afternoon. I've actually found that music is more distracting to me during work hours since I started taking it. While I still enjoy listening to various types of music for recreation, I don't play music while working anymore.

I would definitely say it is not addicting in the manner that coffee is. On vacations and at times I didn't have my prescription with me, I've gone weeks without taking it. There are no withdrawal symptoms, other than the fact that I would be excessively drowsy again, especially in the afternoon. If I stop drinking caffeine, I will suffer migraines for about two weeks.

I will agree with the part about broad focus vs narrow focus. I can think better about large system design late in the evening. When I am working on an architecture problem during the afternoon, I find myself frequently rat-holing. I'll focus on one specific part and just keep going back to it over and over rather than spending enough time at the higher level.

Clearly you have a medical condition you're treating with modafinil which will make the way you respond a bit different than a "normal" person. It's interesting to hear the differences in response.

Your symptoms sound very similar to mine. I eventually had a large vitamin, neurotransmitter, hormone, and adrenal panel done, including saliva and urine samples throughout the day, and blood of course. I was severely deficient in vitamin D, very low cortisol, and notably low B12. Since starting to address these issues, my life has improved significantly. If you haven't had similar tests done, I encourage you to do so.

I've had normal blood work and an adrenal panel. Don't know about the more advanced stuff you are talking about. I'll bring it up with my doctor, and I thank you for the advice.

From as early as I can remember until about 14, I was a dangerously deep sleeper. I only sleep-walked a couple times, but there were times when I had extended, apparently-waking conversations with people, then had no recollection of them.

I could sleep through people talking, bouncing on the bed next to me, the TV, people clapping, etc. I would fall asleep any time I was not actively doing something. Sitting in class, sitting in the passenger seat of a car, anything where I wasn't actively thinking.

Around 14, I transitioned into symptoms like you describe here. I slept less heavily (though still very heavily) but I could sleep quite a bit, and in the afternoon, it would be willpower vs. drowsiness.

Around 18, I transitioned into what I now think of as a 26-hour day. Every day, I could not sleep until I was exhausted, which made me chase the clock around the day. This was obviously disruptive to work schedules and other normal social life.

Around 22, I transitioned into a pretty normal sleep schedule.

I don't know what changed in any of these cases.

Another oddity: I am able to regularly just not sleep at all, or sleep very little for days on end. I've been up for 72 hours dozens of times. It's quite clear that my functions decline, but 48 hours is not a big deal and longer is possible if there's some compelling reason.

Possibly related, my mother has had sleep problems here entire adult life, very rarely able to sleep more than 4 hours in a night.

I've never taken modafinil but have considered it quite a bit. I mostly think I shouldn't mess with it because I'm lucky enough to have a relatively normal sleep cycle now.

You should probably get a sleep study done.

> I could easily sleep for 12 to 14 hours a day if I let myself.

This is a very common symptom of obstructive sleep apnea. Did your sleep study test for it?

Yep. It seemed that their primary focuses for the study were sleep apnea and then narcolepsy. When they didn't find anything there, the looked at a few other things and then just gave me the general diagnosis.

I found out I'm a slow caffeine metabolizer.

I like coffee, a lot. I need a few sips to feel like a person in the morning, but that's it (totally a mental/addiction thing). I enjoy the taste and experience of the beverage, but it doesn't do anything for me.

I found out its in my DNA. Genetically, I'm a slow caffeine metabolizer. I can probably stand to lose 10-20lbs, so that extra weight is affecting my metabolic rate too. I don't exercise enough, so that slows it down more as well.

For a few reasons I don't feel the need to try Modafinil, but an alternative to caffeine would probably work wonders for other people like me.

Very interesting! I'm curious: what's your fitness level, and does regular cardio (say, 30 minutes per day) have an effect? What about scheduling a 30 minute nap in the afternoon?

I'm not sedentary although I don't currently have an active fitness routine. I have maintained a weight and BMI within the typical recommended range with relatively no effort throughout my adult life. I tend to pace or walk a lot during the work day instead of sitting. Especially when thinking about problems. The last time I had a dedicated exercise routine before I was on medication tended to increase my afternoon drowsiness when I exercised in the morning before work, and had no noticeable change on it when I exercised in the evening.

I recently went through a month of physical therapy because of a back problem. That had me doing a light cardio workout 30 minutes per day three times a week (plus stretches and such on the off days). I was still taking my prescription during that time, so I can't say with certainty how that would have affected me, but there wasn't any noticeable change in my energy levels or sleep needs.

An afternoon nap or two is almost a necessity on any day I'm not taking my prescription. I can't say as I have ever tried specifically scheduling them into my work day though. Napping tends to be something I resort to when I can't shake off the drowsiness by walking or a snack.

> I used a (legal) drug called Modafinil

As far as I'm aware, in both the UK and the US, it's legal only as a prescription drug, i.e. if you buy it online without a prescription it is no longer legal.

Your description of the subjective effects of modafinil sound almost identical to those of Adderall (d-amphetamine). Adderall has a very well established short-term safety profile in therapeutic doses, but long-term use, especially at moderate to high doses, can lead to severe dependency and a host of health problems, in a very similar manner to cocaine. If what you say is true that Modafinil doesn't have the high addictive potential of amphetamines and cocaine, that sounds very appealing, but taking any drug even once if it's too new to know if there are long-term side effects from short-term use really scares me. I'm glad you conclude that sleep, nutrition, and exercise are preferable.

P.S. Wikipedia says Modafinil is Schedule IV in the U.S., which means that, like cocaine and morphine (Schedule II), Modafinil is illegal unless you have a prescription.

It's not that similar to Adderall or other amphetamines. The mechanism of action is different. There is some overlap in effect but it's quite different. Amphetamines will provide intense focus and are generally short lived. Modafinil will provide improved focus and alertness and is long lived. The focus is nowhere near as intense.

Adderall and cocaine are even less similar. Cocaine is purely a psychological addiction. Amphetamines have both psychological and physical addiction. Modafinil has little to no addiction. Over time your body will get more efficient at breaking down modafinil down so you may need to increase dose but that's it. There are studies done over years but there aren't any extremely long term ones yet.

While still illegal schedule IV is nothing like schedule II. LE generally doesn't care that much about IV. I've read about schedule IV drugs being opened by customs and allowed through. Think of IV as less than being caught with a joint.

Two points I didn't see about modafinil that I've found: 1) There's a long lag from the I take it until the time it kicks in. I read somewhere that it has to be processed by the liver once and the results of that are what actually has an effect. The upshot is, if I take it after about 11am, I will find myself awake after 1am. So for me it's early or not at all.

2) As a hangover/sleepless night cure. Modafinil is a great "fixer" for a slow d-r-a-g of a day. By noon I usually have forgotten I started the day hungover.

I generally take 50mg for the mildest effect, or sometimes 100mg if the need is greater.

My personal experiences with modafinil's effects are similar to the OP's. It increases my focus more than caffeine but not like Adderall. It completely clears away brain fog and eliminates sleepiness. I find it lasts 6-8 hours for me, depending if I'm sleep deprived or not.

I found that if it's evening, I'm tired, and I take it that it may take up to 2 hours before my alertness improves. Normally it's about 1 hour.

Other than terrible smelling urine I don't notice any side effects.

Modafinil also seems to be synergistic with caffeine. I can take half the caffeine with the same or better effects.

I tried provigil for two weeks and it made me feel like a zombie. I was less sleepy but I felt kind of 'hazy', like there was something between myself and my thoughts slowing down the interaction. It did make me slightly more productive, and able to completely focus on boring tasks.

One interesting side effect is that it made me a bit more social and during those two weeks I had dozens of extremely boring (in hindsight) conversations with random co-workers. It seems to lower my threshold for boredom more than anything.

Another good take on modafinil:


  Modafinil is also compared to amphetamines (which are
  often used either for recreation or to treat ADHD), since
  its effect is somewhat similar. Generally, the comparison
  states that amphetamines are bad for you and that 
  Modafinil is not as bad because it "works differently",
  but there is probably more overlap than the proponents of
  Modafinil would like you to think.
There is one massively huge difference between amphetamines and Modafinil.

Modafinil is not addictive.

I have a prescription for Modafinil (required in the US) and have been taking it for over 5 years. Getting the prescription was fairly simple and required going to a sleep doctor and getting a "sleep study".

I would never have thought of myself as narcoleptic, although I remember frequently being unable to stay awake in high school math class. I think some would characterize me as "a sleepy guy" and I do have to be careful while driving late at night.

I don't take it on weekends, or vacations. Even for up to 3 weeks or a month, I'll go without Modafinil.

Taking Modafinil keeps me alert and excited about my code and my business.

Not taking Modafinil helps me relax and not think about the stress of running a business. I enjoy things like TV and Movies a whole lot more. Playing with my kids is also more fun when not on Modafinil.

But when I need to get back to work, within an hour of taking Modafinil, I am excited about the code in front of me and can work productively for 12 or more hours per day. When evening comes and you know you need rest, there is no temptation to take more Modafinil and work through the night - although that would be possible.

On more than one occasion, I have forgotten to take Modafinil before work in the morning. These days were much less productive, filled with self-promoted distractions and much less excitement about my work. But more importantly, there is no urge or need to take Modafinil; so much so, that I am able to forget about it completely.

These non-addictive characteristics are completely unlike amphetamines (which I have also unfortunately tried in my more distant history).

Addiction is not something that is just in the mind. Everybody who takes amphetamines or smokes cigarettes on a daily basis, will eventually become addicted. Some are able to overcome that addiction, others are not, but the physical addiction is a certainty.

No one who takes amphetamines on a daily basis will ever forget not to take them, nor will they enjoy a 2 week vacation without them. Same goes for the smoker without cigarettes.

Modifinil is quite easily forgotten for long periods of time. I think it is important to note this difference.

Addiction is not just in the mind

Addiction, in rats at least, appears to be more in the environment than the body. Rat Park[0] is a fascinating experiment demonstrating this.

[0] http://en.wikipedia.org/wiki/Rat_Park

Thank you for bringing up the Rat Park experiment.

The Rat Park experiment is often conveniently ignored because it essentially debunks a lot of common 'wisdom' regarding drugs. It's hard to villainize certain drugs as 'bad' and evil' while endorsing others in light of the Rat Park experiment, which shows that 'bad' drugs aren't chemically 'bad' - they're just taken in a 'bad' setting.

Fortunately, the theory is now becoming harder to ignore, because that's the basis of a lot of effective modern drug treatment, which tries to identify the underlying cause of drug addiction (the environmental/behavioral problems that cause an individual to abuse drugs), rather than focusing on the drug use itself. That's not saying that drugs don't have a physical impact - they do - but if drugs are being used as an outlet to compensate for environmental factors, then removing access to those substances will just cause the underying problems to manifest in other (potentially worse) ways.

It's the difference between treating the symptom of a disease and treating the disease itself. Yes, you might want to take cough medicine if you have lung cancer, since it'll help with your symptoms, but you'd be a fool to think that that's going to cure the tumor that causes you to cough.

This theory is very powerful, because it means that you can use the same techniques to treat drug addiction and other psychological ailments like PTSD, anorexia and self-mutilation, which are themselves often best thought of as psychophysiological responses to environmental factors.

Interestingly, if you really want to use physiological symptoms as the basis for determining whether a drug is addictive or not, then alcohol is probably the most addictive substance known to man. If you ever want to give yourself a scare, look up some of the symptoms of acute alcohol withdrawal (which can actually kill you, after a long and painful bout of delirium tremens and worse).

TL;DR: Addiction is best thought of as a mental response to environmental factors. So, in a sense, it really is 'all in the mind'. Or alternatively, not at all in the mind, and all in the environment. Whichever way you prefer to think of it.

Furthermore, the article author is really stretching it with this statement:

"Generally, the comparison states that amphetamines are bad for you and that Modafinil is not as bad because it "works differently", but there is probably more overlap than the proponents of Modafinil would like you to think."

This has nothing to do with "proponents of Modafinil" - they work in different ways on the pharmacological level. The mechanism of modafinil is still being analyzed but it has been shown fairly conclusively that they operate differently.

Actually, I remember reading an article (on HN no less) that said that some studies had found that actually Modafinil worked similarly to amphetamines. Unfortunately I can't find the link for it anymore...

I take Adderall, but not on the weekend. Always be careful when using phrases like "always" or "no one." I would not characterize myself as addicted to adderall either. Many times I have actually quit adderall and tried other ADHD medicines, but come back to adderall because it works better than the alternatives.

My body seems to have no problem stopping or starting amphetamines.

Just wanted to throw out there: please don't start any drug meant to impact the way you see the world without supervision (preferably, professional supervision). If something bad/weird happens, you might not be the first person to notice, especially if the response is emotional/perception based.

Getting a full nights sleep every night does wonders for concentration as well. Don't think of your body as the jar your brain walks around in. They are very tightly linked. If I wanted the effects he describes I'd spend 30mins on the elliptical.


> I usually dose with a cocktail of piracetam, choline, and a small amount (100mg or so) of phenibut.


I'm not the person who you directed your question to, but Piracetam and Choline help with increased cognition, focus, memory recall, and mental stamina. I haven't taken Phenibut, but it appears to reduce stress/anxiety.

Trying to hack the body like this is the equivalent of fiddling around with some extremely complex code that you have no idea what does (in production, on an infinitely complex system with zero unit test coverage).

Your comment is nothing but a metaphor for fearing the unknown.

that's how I justify my drug use, too

To some extent that's true for all drugs (as well as all foods). It's like poking random numbers into memory and restarting your Asteroids game to see if you get 65,536 extra ships, or if the process locks up.

The music also made a big difference. Listening to Infected Mushroom while high on Modafinil and coding up a storm made me feel like I was some kind of insane coding machine that could complete pretty much any coding task in record time.

Hilarious :)

On a more serious note - this sounds a lot like taking Ritalin. I was just as productive if I was well rested, ...and working on something I cared about. - this isn't always an option. Sure, heavy use of anything isn't good. Lest we forget it's a drug after all, even regular use might be too much for some.

I really liked the article and the approach on things.


I'm glad someone else noticed the mention of Infected Mushroom. I had many good (no Modafinil, just caffeine) coding binges listening to it years ago. After a while it gets too much and you move on to Oakenfold mixes, Daft Punks' Alive 2007, etc, but if you've never coded to Infected Mushroom's Classical Mushroom you need to try it...

Thank you for writing this, it articulates everything i have felt about it perfectly! Eerily similar to my experiences. It has always bothered me that people think these drugs make you smarter, because they dont. I think of them more like shots athletes get in hurt muscles- the shot didn't make you stronger, you just dont feel the pain anymore, at the expense of long term health. Only in very special circumstances is that worth it.

Seems like there's a lot of consensus here that Modafinil has no known dangerous side effects. I'm a little curious and concerned about the potentially fatal skin conditions (SJS, etc.) mentioned in the wikipedia article though:


Anyone know about this? Is this a race-specific problem? Or just not as dangerous a risk as it sounds?

> Anyone know about this? Is this a race-specific problem? Or just not as dangerous a risk as it sounds?

Look carefully at the FDA information and run the numbers to decide for yourself: http://www.gwern.net/Modafinil#side-effects

I bought pack of generic modafinil (do not remember exact brand). It was manufactured in India.

It had no effect on me. I tried up to 4 100mg pills at once (i.e. I started with half table one day and each day increasing dosage). Although, I also suspect it might be a fake, since I was buying from some online "pharmacy". Provigil both too expensive and require doctor's approval.

Just found about piracetam, thanks to this thread. just ordered :)

Quality varies significantly between Indian manufacturers. Sun Pharma Modalert is a known quality brand.

Interesting timing, just when I was about to swallow a 100mg pill of modalert to pull an all nighter and I find this on HN. I usually keep a few of them in drawers at home and work for one of those `rare occasions`. Tonight happens to be one of them.

Someone brought this up last time we talked about this on HN so I thought I would mention it here. Modafinil is technically a _stimulant_, not a cognitive enhancer (like piracetam).

Er, piracetam is usually described as being a nootropic, and substances like nicotine or amphetamines or caffeine as being cognitive enhancers due to the existence of known decreases in performance; because modafinil has few to no known mental penalties, it is usually described as being a nootropic and not a cognitive enhancer.

Stimulant, on the other hand, is a completely cross-cutting orthogonal classification. A drug which enhanced transfer of information into long-term memory and nothing else could rightly be described as a nootropic but not a stimulant.

Nothing says a "cognitive enhancer" can't be a stimulant. Nootropics can be anything.


I have heard it very difficult to get a prescription for Modafinil, even if you have work sleep shift disorder because most doctors aren't used to prescribing this drug.

Prescription of modafinil for any reason other the conditions for which it's indicated (hypersomnia or accepted off label use) is highly irresponsible of physicians.

For anyone that's interested, when he says "online pharmacy", what that really means (at least in the US), is:

A. An Overseas pseudo-legal (at best) operation that will send you the drugs discreetly in an envelope. The success rate of getting it through US Customs will be good as long as it's not shipped from a hot spot and does not come in a package.

B. A Mexican drug dealing operation that smuggles the drugs across the boarder to a US stash house, which then takes orders online, receives payment for the order via MoneyGram, and ships the orders out from within the US overnight by FedEx to your door steps.

> A. An Overseas pseudo-legal (at best) operation that will send you the drugs discreetly in an envelope. The success rate of getting it through US Customs will be good as long as it's not shipped from a hot spot and does not come in a package.

Very good. I know an online modafinil seller; she tells me that the failure rate in the past year or two for her has been <5%. This accords with my own experiences.

C. The Silk Road.

Modafinil on Silk Road is about twice the price of online pharmacies and most of the people selling it appear to be international.

We're not supposed to talk about option C) here.

I would agree that occasional use isn't a good idea. I've done that and it really is more trouble than it's worth. That said I still do it. If I have a day where I'm extra lazy I'll take a Nuvigil (Armodafinil, which is the active isomer of Modafinil) and be productive but with some side effects which include



Some inability to focus between tasks

I've also found dosage has a sweet spot. I wouldn't take less than 150mg of Nuvigil as lower dosages make me strangely more nervous.

Stuff I've tried over the course of the last year or so:

1) Caffeine pills, 200mg each, around $4 at Walmart. I wrote about this before. The effects are far superior to coffee. More consistent, no intestinal distress. I could take one upon waking, and another around lunchtime. I haven't been taking them daily for a few months now, and my daytime productivity is certainly lower.

2) Piracetam with Choline Citrate and, sometimes, Centrophenoxine. I would usually take around 2g Piracetam and 1 - 2g Choline in the morning, and repeat the dose in the afternoon. It definitely has some effect, but I can't say whether or not it's really a positive one. I suspect that the key (like what the author of this article mentioned) is to have your tasks laid out clearly. I definitely had a few weeks where I got a tremendous amount done, but it was early on in the project when I knew exactly what to do, and how to do it. Overall, I say the jury is out on whether or not Piracetam has a beneficial effect on me. It might increase crankiness, which I've never read about from anyone else.

3) 1,3 Dimethylamylamine (DMAA), one of the three primary ingredients in Jack3d (a very popular pre-workout supplement). I settled on 2x20mg DMAA pills and 1x200mg caffeine about 30 minutes before my workout. Initially, I would get a mild sense of euphoria while walking to the gym. After about three doses, the euphoria seems to have gone away, but I am still able to power through my weight lifting routine without hesitation or procrastination. I've done this every other day for about a month now, and as long as I'm getting sufficient sleep, the effects seem consistent. I generally take it at around 5pm, get to the gym at 5:30, work out for 60 - 90 minutes, go home, and eat. By 11pm I'm very sleepy, and I don't have any more trouble getting to sleep before midnight than I normally do. Like most Internet/information addicted people, I certainly have my nights of senselessly clicking until the wee hours, but this seems unaffected by the DMAA + caffeine. By the way, I wear a heart rate monitor when experimenting with this, and I don't think I would do any intense cardio while on it. I don't believe I'm anywhere near a problematic dose level, but I'll err on the side of caution.

4) Cardio. I started feeling depressed heading into the holidays, so I did 30 minutes of moderate cardio (140bpm heart rate) every day for two weeks (I typically do a lot of cycling in the summer months, but not so much in late fall through early spring). My depression lifted very quickly. In general, I'm of the opinion that 30 minutes daily or every other day will do quite a lot to increase general alertness throughout the day. I'm going to experiment with something even easier: taking a morning walk first thing in the morning every day.

I haven't tried any of the pills you've mentioned, but I'll second #4. I run all summer and fall, but take the winter off. I find that I'm much less happy and more irritable when I'm not exercising regularly. I'm sure there are a billion [1] studies showing that exercise is good for your mental health, but I'm lazy and don't feel like googling for one.

[1] An exaggeration.

The thing that I found particularly interesting about my cardio experiment is that I'm already more fit and active than average. Every other day (barring the occasional extra rest day), I'm at the gym, doing 60 - 90 minutes of free weights. My heart rate is often 140 - 170 when I come off a set, and I pretty much jump on the next set when my heart rate hits 125. By the definitions I found, that is technically cardio, yet doing 30 minutes of daily bike riding still seemed to have an effect.

I've also found that having a bright light helps, particularly in the darkest of the Pacific Northwest winter months.

I started taking 2,000iu of vitamin D upon waking, too. This may or may not help with wakefulness and may or may not assist in combating depression.

An experienced running coach has recently opined that spending an hour in the gym doing strength is about equivalent to 10 minutes of running.

Part of the reasoning could be the activation of different energy systems. Lifting activates the anaerobic system, whereas sustained cardio activates the aerobic system and dips into the anaerobic only at higher levels of effort. The anaerobic system transmits something like 30+ ATP (energy currency of the body), whereas aerobic is 2 ATP [1]. That might explain why you experience this difference.

[1] http://ksuweb.kennesaw.edu/~vking2/PhotosynthesisandCellular...

Note that many 200mg caffeine pills are scored and can easily be split in half. You may find 100mg to be a better daily dosage; 200mg at once makes me too jittery.

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