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L-theanine, a constituent in tea, and its effect on mental state (2008) [pdf] (nhri.org.tw)
260 points by lainon 6 months ago | hide | past | web | favorite | 158 comments

> The control solution was 100 ml of cool potable water and the L-theanine solution was prepared by dissolving 0.5 mg powdered L-theanine (Taiyo Kaguka Co. Ltd., Yokkaichi, Japan) per Kg participant body weight in a tea infusion (total L-theanine 50mg/serving).

So, there was a statistically significant difference in brain activity between participants who drank cool water and participants who drank (hot?) tea with added L-theanine. Curious setting.

I find drinking a good cup of tea or other tea-like infusions to be quite relaxing. More so if I get to step it myself. I suspect that there’s a meaningful non-chemical effect, and this study has no ability whatsoever to discern whether L-theanine is involved.

Try drinking just the hot water by itself. It's surprising and amusing how much of the effect you get. Pretty sure it was a Paul Graham tweet that pointed this out to me.

Hot water with lemon, morning or night, is excellent.

With a touch of honey

There is a Russian beverage made by adding a ton of good quality honey to hot boiling water that is supposed to be an excellent cold remedy. No idea if it actually does anything, but it is delicious and soothing.

It's not just Russian. It's a common remedy. As you say, I don't think it does anything - a cold is a virus, and any antibacterial property of the honey would be useless on a virus. But since it is so tasty and relaxing, it might be able to help you divert more energy to your immune system or something. idk. I merely speculate. It's fun to drink though.

It's thought the honey is the body's way of getting sugar during a viral infection, in which glucose might be a key factor in fighting the virus off.


Belarusian here. We use milk with honey. I don't think it kills virus, just helps with the soaring throat and "softens" the coughs. Another popular medicine: vodka with pepper

Never liked either

Some people recommend hot beer.

I think honey is supposed to have natural antibiotic properties.

But also be careful about using too much of a ton of honey. Apparently the body will naturally purge an excess of honey ingested at once.

It might work as a antimicrobial (ie, applied externally) because it contains hydrogen peroxide but as to whether it can do anything about a cold (which is after all a virus) is another question.


The enzymes react with moisture in your skin to create hydrogen peroxide - read that somewhere. It also cuts off air flow to any bacteria. I think the sugar also acts against the critters.

Honey loses these effects when put into water over 44 degrees Celsius warm though.

That's why you should first make your tea, wait till it cools off, and only then add honey.

Citation needed, please.

As far as I know, honey has two material effects: it is tasty, and there are some studies suggesting it’s an effective cough suppressant. I’ve never heard of either one being temperature dependent.

I’ve heard people claim that local honey has anti-allergy properties. I would certainly believe that the active ingredients in pollen are destroyed at high temperatures. But AFAIK any purported benefits are entirely unsubstantiated, and the FDA notes that bee pollen can be actively dangerous to people who are allergic to the pollen.

P.S. I drink my tea above 44 C.

Honey contains glucose oxidase from bee guts, an enzyme that produces hydrogen peroxide in the presence of glucose and oxygen[1]. The accumulation of small amounts of H2O2 is what makes honey shelf stable.[2]

It's probably also what causes honey to have antibacterial properties when you put it on a wound.

That's not to say that it would have any effect on bacteria in your body if you eat it.

The enzyme is deactivated or denatured somewhere in the neighborhood of 50 C. [3]

Honey itself has antibacterial properties but there's no evidence I can find to show those properties translating to your body after you eat it. It makes sense that honey is effective to help treat wounds because it's still honey, not mixed up in your stomach and beyond. I'd bet stomach acid would do a fine job denaturing that enzyme as well, heat be damned. So maybe don't boil your honey if you're going to put it on a scrape, but drink your tea as you like. I personally really dislike honey in tea.

1. https://en.wikipedia.org/wiki/Honey

2. https://pdb101.rcsb.org/motm/77

3. http://www.jbc.org/content/278/27/24324.full "The midpoint for thermal inactivation of residual activity and the dissociation of FAD was 59 °C"

If you put honey on a wound its osmotic properties alone have some antibacterial effect.

Honey is also pretty much the only thing that kids under 12 months old should not eat because it could cause botulism, which is fatal for them*

* https://www.babycenter.com/404_when-can-my-baby-eat-honey_13...

> Apparently the body will naturally purge an excess of honey ingested at once.

That's a new one on me. Where did you hear that? What do you mean by purge? Vomit?

I don't remember where I heard that. Looks like I'm wrong and the worst it may do is cause stomach cramps and bloating.

It's no longer antibiotic once it gets wet.

Eat too much anything and you will naturally purge.

Why is honey no konger antibiotic once it gets wet?

Toss a little tea in there and it's pretty good.

Skip the lemon and swap honey for sugar and you can make me one while you're at it. Twinings or PG Tips preferably...

A don't forget to add a tea bag and it'll be perfect. :)

And a shot of strong Irish Whiskey!


Hot water, a large measure of Powers Whiskey, honey and a chunk of lemon with cloves pushed into the skin. Leave to steep for 6-7 mins, give it a stir.

Top notch for the alleviation of colds and, well, anything really :)

And a little camellia sinensis.

Those who say there's nothing like a nice cup of tea for calming the nerves never had real tea. It's like a syringe of adrenaline straight to the heart!

When Alice first drinks Grasshopper Tea

sorry, could not resist the quote :)

... yeah why didn't they compare the same tea infusion with and without l-theanine?

doesn't tea contain l-theanine?

Yes it does. But not in large quantities. The study doesn't seem to suggest very large doses of L-Theanine were used either though. I usually take 5-10x what they were using in the study :P maybe I should reconsider my dosing.

Massive "slight of hand" omissions like this is scientific papers are really problematic.

The research isn't bad, but the implied finding is. It should say "Hot water with tea flavouring and L-theanine has a measurably different effect on humans than cold water".

This paper will no doubt lead to a whole wave of dietary additives, fooling millions of people into thinking they're doing something with scientific basis.

What can the science community do about it?

Restrict papers without peer review? Require per-institution "scientific method" inspectors? Something else?

In case anyone is curious about L-Theanine, it's very often used by people with interest in Nootropics for focus along side caffeine. The Theanine-Caffeine stack is considered to be the sort of entry or gateway into nootropic territory.

Yes typical dosing ratio is 1:2 caffeine:theanine.

With typical dosing being 100mg caffeine:200 mg l-theanine

You can buy l-theanine pills and take it with coffee. If you'd like it from nature, Matcha has the highest L-theanine content. This is because L-theanine is an anti-oxidant made in the roots and sent to the leaves to prevent against damage from the sun. Matcha tea plants are kept in the shade for the last couple of months, so they build up the theanine and it is not used up. The full leaves are then ground up, but will only contain around 40 mg per serving, which is why I generally recommend supplementing it. Suntheanine has a patented form that is made in a biofermentation process that yields nearly 100% pure L-isomer theanine.

Also interesting is that, while L-theanine the molecule wasn't "discovered" until 1949, the Japanese ceremonial tea scale has been for hundreds of years, organized by increasing levels of theanine content.

For some reason Suntheanine has no effect at all on me, though regular L-Theanine pills and even iced matcha or regular green tea all have huge effects.

There are some cheaper tea varieties than Matcha that were also kept in the shade, e.g. Mecha, Kabusecha, Gyokuro.

I can attest, I use Xenadrine (Weight loss supplement) for years now, not everyday or anything just when I'm finding my focus waning. Xenadrine has caffeine/green tea, hydroxycitric acid, and some other weight loss related herbs, but the caffeine/l-theanine is what I feel, deliver on the focus/mental energy.

I've tried other caffeine products and l-theanine alone, nothing had that great effect as Xenadrine did, I'm not sure if maybe one of the other ingredients is a nootropic either, could be, I imagine, or could just be the quantities.

Coffee and normal caffeine doesn't do much for attention/focus for me... but I drink way too much soda..or did.. (weaning off)... About to do keto for a few months.

Out of curiosity, is there much discussion in that community of other xanthine stimulants like theophylline, theobromine, and 8-chlorotheophylline? I take dimenhydrinate = 1:1 diphenhydramine + 8-CTP to relieve nausea, and from the feel of it I’d like to try 8-CTP on its own (or in conjunction with L-thea) because (like theobromine) it seems to be nicely stimulating while give me less anxiety than caffeine. Seems to be fairly cheap at around USD 65¢/g from chemical supply companies, but I don’t know how much I really want to get into that “just buy it and try it” world if it (or something like it) is available OTC.

I would be careful with dimenhydrainate as it is found to be related to dementia likely due to the fact that it's anticholinergic. It's basically the opposite of a nootropic.

Yeah. :/

I was aware of this already—thanks for bringing it up though, since I think it’s important that people be aware of it. Unfortunately I haven’t found an equally effective yet safer replacement for nausea & allergies. Ginger works pretty well, but iirc that’s because it’s also a mild anticholinergic/antihistamine.

The only problem with theobromine is I think it raises your heart rate. That seemed to trigger headaches for me. Love how it makes me feel otherwise.

Theobromine is theorized to be what causes some people (I'm one of them) to get migraines from chocolate.

Although the research in this area is very inconclusive afaik, it could even be placebo.

I believe it. But so many things are that way. Headaches suck.

Here is the info: https://www.webmd.com/allergies/news/20160509/anticholinergi...

I would recommend avoiding anticholinergics!

Unfortunately, it's yet another GABA agonist, and after it wears off, I get severe brain fog. Also, it has diminishing returns. If I take it more than 3 days in a row, it does nothing. So many of the supplements and nootropics that I've tried for programming are the same way. The only three that I take now are caffeine(daily), nicotine(rarely) and adderall(very rarely).

  So many of the supplements and nootropics
  that I've tried for programming are the same way. 
What have you taken so far? Could you expand? Especially nootropics.

I see caffeine as a net negative for mental acuity. Just makes people want to punch to the deadline or skip from topic to topic.

Have you tried Ar/modafinil?

There are too many deaths linked to modafinil for me to try it.


Armodafinil is bad for your liver.

L-theanine completely destroys my ability to sleep. I've tested a few times now. Dosage used was 100mg, taken early in the day. It's like I get stuck in super light sleep where I'm practically dreaming but awake.

Agreed. N=1 anecdotal evidence, but I generally can't get to sleep after green tea in the afternoon.

Green tea does have caffeine, so I'm not sure if your side effects are related to L-theanine. I also have trouble sleeping as well when I have afternoon caffeine. I don't feel awake, but I just cannot sleep. It took a while for me to associate this with late caffeine.

I love the stuff!Improves caffeine absorption and is great for performance anxiety. I use it before bike racing or public speaking. The mental state I would describe as clear, calm, present and focused.

L-Theanine fixed my mild stutter and has helped me tremendously in the gym with focusing on every rep. It's a wonderful supplement.

I especially love biking after having some, I get into a great flow state and can go much longer.

What dosage do you use( coffee and l-theanine), how do you take them (regularly, at standard times or occasionally)? Do you use any other nootropics?

I tried it, several times and at different dosages, but it doesn't work for me. No effect whatsoever. I wonder why ...

L-theanine is a structural analog of L-glutamate and L-glutamine, amino acids that are common in neurotransmitters, so the effects of taking it will be highly variable by person just like any psychiatric drug - although the effects are far less pronounced so it's much safer (liver toxicity aside). Chances are, your diet already has plenty of those building blocks for your unique brain chemistry so you're at an equilibrium where adding more L-* just gets balanced out by the body or it could be that it's saturated so you have to try other levers (although that is much harder since metabolic pathways are nonlinear and incredibly complicated).

Thank you for this explanation.

liver toxicity aside

That's what I was looking for. I recall a burst of interest/hype (choose your word), several years ago, about L-theanine. One company/salesman (the very prominent-looking, TV type, although I think this may have been via one of those suspicious-looking PBS specials [1]), was promoting it in a topical cream. Apparently, it would pass from that into the bloodstream.

There was little if any discussion in that... "pitch" about dosage limits. 'It sooths you. Rub it on. Rub on some more...'

I wondered. And more recently, I finally started seeing reporting of downsides -- although I didn't see much. Liver toxicity.

Like so many other drugs/supplements (choose your word), a lot of harm to reputation and perhaps also people is done, when no work or discussion is included about effective and safe dosage.

Like the "self-taught" herbalist my acupuncture friend had a (non-romantic) "thing" for, years ago. "Intuitively" brewing up pots of herbal tea for people, in his home. Not wanting to disappoint her, nor offend him, I drank some. And felt like crap for two days. Thank goodness my liver made it through unscathed.

I don't want the FDA shutting down everything on behalf of the pharmaceutical companies (who've played their significant roles in side-lining a lot of effective but unprofitable -- for them -- treatment). But I would welcome more intelligent conversation about and thoughtful approach to these things.


1. PBS == Public Broadcasting System, i.e. publicly funded television, in the U.S. That's been taking on more and more commercial tinges, in return for corporate sponsorships, as the public money has fallen short.

Just FYI Herbal teas generally don't contain tea (camellia sinensis) and likely don't contain L-theanine as a result.

Thank you. No, I wasn't thinking of "herbal tea" in that sense. Not of L-theanine.

Rather, of people promoting [product] without having real knowledge of it, including appropriate application and dosage.

This would be more in the vein of traditional Chinese medicine. Only, "intuitively", without the normal training and basis in extensive empirical observation condensed into an effective curriculum, apprenticeship, or similar proven method of conveyance.

"L-theanine is a structural analog of L-glutamate and L-glutamine"

Does that mean that you could get the same effect from consuming MSG?

Glutamate doesn't have any psychoactive effects because it doesn't cross the blood-brain barrier (to a significant extent). You are correct that theanine and glutamate in theory should have a similar effect on receptors, but receptor activity is only half the story. Other factors like transport and metabolism are important too. For example amphetamine and phenethylamine are structurally very similar, but will have a vastly different effect on your body.

> L-theanine is a structural analog of L-glutamate and L-glutamine

Interesting. I've tried L-glutamine, also several times at common dosages, and it makes me feel strange, like calm on the one hand, while edgy on the other hand. It's difficult to explain, but my voice felt calmer and my ears felt more anxious. I first thought the product I bought was contaminated, so I tried two more brands, with the same effect.

One thing is for sure: L-glutamine has much more effect on me than L-theanine (which basically does nothing).

interesting. theanine makes me very frustrated when i take it. ive dialed down the dose a few times, but stil get irritated. your explanation if helpful.

And this reminds me of trying Zoloft and a couple of other things.

15 - 30 minutes into one starter dose, and I felt terribly worse.

No professional explanation. It was only years later, when I ran across reporting about serotonin poisoning, that I had a possible explanation. The symptoms certainly fit.

A friend has used Zoloft for years, to what she feels is positive effect. And in many ways, we are fairly similar -- certainly, our psychological profiles align substantially.

Nonetheless, what works for her, does not for me at all.

Serotonin syndrome is nasty, nasty, and more nasty.

I've experienced it once, after a particularly incompetent new pain management doctor made me try a cocktail of anti-depressants for pain relief. (their reasoning being that "it's all in your head"). I felt utterly awful, pulse racing, severe anxiety and horrible mixing of panic and terror.

It's imperative that people on multiple medications take Serotonin Syndrome very, very seriously. I'm very sorry you experienced it, I wouldn't wish it upon anyone.

(The pain management doctor was fired a couple of months later by the university hospital. Complaints from patients, nurses, pharmacists and insurers had been mounting.)

I occasionally have the same experience when taking melatonin. It's bizarre.

I'd say 10-20% of the time that I take it, I am unable to fall asleep and don't become tired. The longer I stay away, I feel incredibly restless and twitchy to the point of actual anger. I'll lie awake in bed until 5 or 6 AM (after taking melatonin at 11pm or midnight). It gets to the point where I feel like I need to do some kind of physical activity in order to relax. My eyes and chest often feel heavy but my legs are tense, restless and twitch.

Sure seems like Restless Leg Syndrome just from proof reading this. Based on my first look into RLS just now, there could be a link to low Vitamin B, which could be triggered from a Saturday of drinking and then expecting melatonin on Sunday to set me up for a productive Monday.

How much are you taking? Melatonin actually is better in small dosages, at least for sleep. I get the 5mg tablets and then nibble on them. I don't take it every night, but one of those tablets will last me like 4 or 5 nights. High dosages (like 2+mg) are supposed to have nootropic effects that don't make you tired. I know I've never fallen asleep with a 5mg dose. Also, light really kills the effectiveness too. If you need to watch TV or be on your computer then turn all your other lights off and turn the brightness way down.

See if you can get it in liquid form. I have a bottle with a dropper; each drop contains 120 micrograms. (So 8.5 drops is 1mg.) I don't use it very often, but if I have to wake up unusually early I'll take 2-3 drops around 20 minutes before bed, and it definitely helps make me sleepy when I'd normally still be awake.

That sounds great. I usually use it when my sleeping schedule gets messed up, either from travel or my natural drift. So that sounds perfect. Thanks!

Didn't know it came in liquid & at doses that low, thanks

5mg, sometimes I take a whole one, break in half or nibble. I'm not sure which amount I've taken when I get restless. That could play into it

This happens to me if I take my melatonin gummies and then try to do something like laundry or dishes, instead of going right to bed after. It's a lot harder to get to sleep so I just take them right before I know I'm going to bed and that helps my sleep quality quite a bit.

I'm not sure that "frustrated" is quite it for me. But I much prefer coffee to tea. After enough sleep, I feel sharp and energetic after coffee. However, with too much coffee, or after poor sleep, I get nervous and unproductive.

But with tea, I just get nervous and irritable. Maybe weaker tea would be better. Or green tea, rather than fermented. Yes?

For what it's worth, I've been diagnosed bipolar, and take modafinil. So perhaps I respond atypically to caffeine vs L-theanine.

what do you mean about liver toxicity? Is L-theanine toxic to the liver?

Yes, in large enough quantities over a long enough time period. The chances of "overdosing" on it are almost zero but the long term stress on your liver can contribute to liver disease. Your liver is basically the toxic chemical treatment plant for your body, taking care of all the things that are too small for the immune system. This includes storing excess amino acids and filtering out poison like alcohol. All that bad (and excess good) stuff, takes work to clear out and the more work your liver does, the higher the risks of cancer and other diseases because more work means more chemical activity, cellular regeneration, and so on.

I wouldn't worry about it unless you're taking tons of supplements every day by the handful or if you're a heavy drinker. However, do get physicals at least once a year with a liver panel that can track if your liver starts to degrade. Liver disease is generally a slowly developing chronic condition tied to lifestyle so you can usually right the ship if you're mindful of the risks.

Did you take it on its own? Almost no effect for many people if taken solo.

Take it with a cup of coffee and the caffeine boost lasts longer and is much smoother.

Anecdotally, I noticed a super mild effect. I drink between 8-10 cups of coffee a day and if I hit that upper limit it dulls the anxiety but not in any pronounced way.

>8-10 cups of coffee a day

Is this... Safe? I mean, if I told me dentist this she would slap me, let alone my cardiologist.

Yes probably. I think the warning against coffee haven't really been based on anything else than "common sense" and possibly that it's a recreational drug.

Maybe it's border line if you already have arrhythmia, but recent studies seems to show positive effects up to that limit, and it doesn't seem to cause arrhythmia.

Might upset your stomach though, but I'm pretty sure your dentist will be happy to polish your teeth for a modest price...


There seems to be several positive effects on breast cancer , diabetes, Parkinsons, ms, and stroke.



In the metaanalysises that I've glanced over 8 cups is on the high end, but doesn't seem to negatively affect mortality.

One of them: https://academic.oup.com/aje/article/180/8/763/2739131

Probably not, frankly. That said, the body will acclimate.

I'm past the "beneficial" range of caffeine consumption, though.

from one caffieneist to another, you may want to cut your consumption in half. at minimum, it saves on bean costs.

Are those ~2.5 dl cups?

I've used it before job interviews and it kept me much less anxious throughout.

Out of curiosity, do you ever take it on its own, or always with caffeine?

i'm almost always drinking coffee. so probably not.

how many watts/kg though?

i do track sprinting, so like 7-20 depending on the event

I've tried it in the past with coffee. It's an interesting additive as it gives you the relaxed tea feeling but with the focus of coffee. Within a few uses the body adapts and more is needed to get the same results. After a few usages I found it not worth the extra effort.

For me, Coffee + L-Theanine = Super Focus. 200MG serving.

I noticed an effect when taking it with coffee, too. I just had some l-theanine as a supplement. I just drink coffee, so I didn't think much of taking it with coffee, so I didn't expect anything. It seemed to "smooth out" the effect of the caffeine. Rather than jittery, it turned it into smoother focus.

Just throwing my own anecdotal experience on to the pile: L-Theanine is very effective for me when taken with caffeine in a 2-1 ratio. As another commenter said, it "smooths out" the jitteriness of caffeine, and this scales up to 200-300mg of caffeine (400mg-600mg of L-Theanine). The focus it provides is the closest legal alternative to adderall that I've found.

If taken alone, it's also pretty good at providing a general reduction in anxiety. I was travelling internationally one time with a co-worker who had a very low grade anxiety attack. Due to the circumstances our options for getting him medication or seeing an actual doctor were limited. I offered him some L-Theanine and he LOVED it, he said it calmed him down just enough the rest of the trip that he wasn't concerned with having another attack. Obviously, this isn't medical advice and ideally he would have seen an actual doctor, but in this case it was really effective. I will say that taking it without caffeine comes with a bit of sleepyness. Definitely a potent combo when taken with Melatonin and a lot of OTC sleep aids will combine the two.

This article mentions that previous studies found L-Theanine has stronger effect on anxious subjects. Perhaps caffeine provides that.

Caffeine also “treats” things like ADHD, sometimes without someone realizing it. I was told I likely had ADHD as a child that wasn’t ever treated/evaluated (because hippie parents) that carried into adulthood and I have basically been self-medicating with caffeine for the last 10+ years.

Nicotine also had positive results in some trials with ADHD. I self-medicate with nicotine gum though I've never smoked.

Try it along with bulletproof coffee (grass fed butter and MCT Oil Powder in the coffee) and keto diet. My new favorite.

"Read This Before You Spend $19 On Bulletproof Coffee Beans":


He's not advocating for the brand "Bulletproof", the coffee recipe itself is simply called "bulletproof coffee", it's the combination of normal coffee (whatever type you choose) combined with MCT oil and Ghee/butter.

Are you taking the caffeine from coffee in pill form or in a cup? Also how long does this seem to last?

I purchased the powder on amazon (Nutricost L-Theanine Powder). It comes with a 200MG scoop and I just mix that into my cup of coffee. For me, it lasts around 2 -3 hours, doesn't impact the taste, and eliminates the jitters that I receive from caffeine.

What is your coffee to theanine ratio?

Not OP, but me 2.5:1 theanine to caffeine. 500mg theanine, 200mg caffeine. It really does wonders for me personally.

Somewhere around 1:2 Caffeine:L-Theanine. I think a standard cup for me is around 95MG Caffeine: 200MG L-Theanine

L-theanine appears beneficial to mood and attention with negligible short-term side effects.

I wonder, though, what long-term side effects L-theanine supplement might cause. I searched several times but most information on long-term consumption is anecdotal.

The best site on the Web for summaries of studies on supplement efficacy appears to be: https://examine.com/supplements/theanine/

"The control solution was 100 ml of cool potable water and the L-theanine solution was prepared by dissolving 0.5 mg powdered L-theanine (Taiyo Kaguka Co. Ltd., Yokkaichi, Japan) per Kg participant body weight in a tea infusion (total L-theanine 50mg/serving). "

Why wouldn't the L-theanine solution be L-theanine in water? Including tea would introduce other chemicals, including caffeine, no?


"AUTHOR DISCLOSURES Gail Owen is an employee of Unilever, which markets food products some of which contain L-theanine and caffeine."

Seems to help me sleep, anecdotally.

I take before bed as well, it helps calm those crazy before-bedtime thoughts and just lets me dooze off

The best working melatonin supplement I've taken has l-theanine in it.

So in order to get to this level without taking supplements, it would be about 2.5 cups of tea? Or more? (Since they seemed to have added L-theanine to a cup of tea.)

Looking at what's contained in black tea, 20 mg, yes. I wonder if this helps explain the popularity of tea and the general idea that drinking tea helps you calm down.

Wikipedia suggests that longer brewing time is necessary to get the full dose of l theanine, for which I'd recommend a quality loose leaf tea, and reuse the leaves a couple times (make several cups consecutively in the same day).

My fancy loose leaf tea habit is about $6 a week, or about one latte with tax and tip. It's cheaper, fewer calories, and I don't get agitated like I occasionally do with coffee on an empty stomach. You still get away from your desk (which I think is half the point of going for a coffee anyway), but not for as long.

My dealer knows that some teas will keep you awake and some that won't. Some will have that info but maybe not know the connection with l-theanine.

Check out [San Francisco Herb Co.][1], quality bulk tea at great prices. This is how we curbed our tea expenses. You will need to buy $45 worth of product for them to ship, but they have a lot of oover great stuff --or get someone to go in with you on an order.

[1]: http://www.sfherb.com/

Indeed, and different types of tea contain different levels of L-theanine. I believe shade-grown green tea (many japanese greens) can have 40-50mg.

Though the other study I looked at found (for their samples at least) that black tea had more L-theanine than the green. (But I've seen the opposite claimed as well. So perhaps it depends on the particular variety and other factors.)

Realistically you also can't chug a hot cup of tea and people usually have it in relaxing settings.

"These data indicate that L-theanine, at realistic dietary levels, has a significant effect on the general state of mental alertness or arousal."

I have tried supplementing with the amino acid in the past. I have tried with 50 100 200 and 400mg The best dose for me was 200mg It makes me very sleepy and it does not help with concentration. I tried to combine it with caffeine but the result was not good. For concentration, coffee is the best for me. For sleeping I use melatonin but only if I pull a long night

Too bad that tea contains so much fluoride.

Outlined in this paper "Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation"


Seems to me that this just says the water used to make the tea has fluoride. And Ireland just has significantly more fluoride than most places.

It's both the water and the fluoride content of the tea leaves, although the tea leaves are the main contributor. The first table in the paper shows this.

Edit: spelling and comprehension corrected; pre-tea morning fog.

Thanks for actually reading, unlike the parent.

> The Republic of Ireland (RoI) is the only European Country with a mandatory national legislation requiring artificial fluoridation of drinking water

So, only a problem in countries that do fluoridation. (I didn't know that that was the case in Ireland. This definitely reduces the chance of me ever moving there.)

Not if you live in New Zealand with naturally low fluoride levels!

The study found that the fluoride already present in the tea leaves was the main source of exposure. Those tea leaves were mostly imported from East Africa, as is the case for many cheap tea bags. Therefore drinking a lot of cheap tea bag tea in New Zealand is potentially not much better.

L-theanine does nothing for me, when I take it with coffee.

If I have to very charitable, it probably reduces jitters that I otherwise get from coffee-only. But I'm not sure if it's a real effect or a placebo.

If I take L-theanine and L-glutamine, I get a euphoric high. Anybody else notice this? How to screw up and up regulate GABA receptors 101...

L-theanine never worked for me. Even tried large doses and felt no difference. Maybe reading such articles causes placebo effect?

no way! When I drank my first cup of Japanese green tea I didn't even know what l-theanine was. Since I felt very euphoric and relaxed after said cup I had to google the components of sencha to find out what caused this very pleasant sensation. However, the intensity of the effect does vary from day to day for me.

People are different.

interesting anecdotal response to the well cited research

These comments represent many anecdotal opinions. That's the value of comments around this article.

Science has proven this can have an affect. But even the study doesn't conclude this is 100% for everyone.


> Gail Owen is an employee of Unilever, which markets food products some of which contain L-theanine and caffeine.

It's interesting how many brands Unilever owns:


This outcome looks positive for their Lipton brand. They might have a good viral marketing department, but that's none of my business.

Unilever's tea beverage market share worldwide is estimated to be 11.1 percent in 2016. Source:Statistica

> They might have a good viral marketing department, but that's none of my business.

Unsure if you are a part of the viral campaign yourself or if it was just a subtle joke...

It depends on him being green.

This image and variants showing how basically every food brand rolled up into one of ten companies was pretty viral around 2012: https://i.pinimg.com/originals/75/0a/0a/750a0a2ae95cc27a45ce...

The only question I have with some of them is what role outside of marketing does Unilever play with some of these brands?

Also, wow I am surprised at how much of the Ice Cream industry they own.

Assuming the data is good and there wasnt bias, the question becomes-Does this frequency between 8-13hz matter for performance?

Is having a 0.3mV2 difference in alpha waves significant?

Ive tried taking lTheanine and it doesnt seem to do much, even if I take many pills.

I've heard and read about the 10hz frequency inducing altered states of mind [0]. I've also heard anecdotally that both water and fire resonate/flicker at 10hz, which is why people focus and get lost in flame and water.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4990355/

cursory research led me to believe that l-theanine on its own doesn't do much of anything. adding caffeine seems to be the ticket to the proposed improvements.

wonder if there's a way to package l-theanine and caffeine together into one supplement. maybe that's what those gas station "super focus!!1" pills use? i might give it a try this upcoming semester, i generally don't mind being a supplements guinea pig.

>wonder if there's a way to package l-theanine and caffeine together into one supplement

It's called "tea".

Not marketed crazily, but widely available, e.g. http://nootropicsdepot.com/caffeine-100mg-l-theanine-200mg-c...

There are plenty of caffeine+theanine supplements available. I take them in capsule form, available from Amazon from all sorts of brands. Beware though, some really overcharge for them.

Brain waves were fine-tuned over many thousands years of evolution.

Stuff which modifies them greatly as this study seems to show probably has some sort of side effects.

Otherwise nature would have boosted them already.

The presumption in your comment is that evolution selects for brain traits which confer some sort of advantage. This ignores the fact that the modern human brain is used very differently than that of our ancestors thousands of years ago.

Is there evidence that the human brain has changed / evolved genetically in the last few thousand years?

A few thousand years is not a long time in evolutionary terms.

> Stuff which modifies them greatly

Like ... food? This is an amino acid, the building block of protein. Many amino acids have pronounced effect in the body or when lacking.

Our bodies are fine-tuned to be somewhat fault-tolerant, but evolution is extraordinarily slow. If our diets diverge over a few hundred years, there haven't been nearly enough evolutionary cycles to compensate for whatever effect that has; particularly if it's minor annoyances like getting jittery with coffee, which was consumed far less as far back as a few hundred years ago.

> evolution is extraordinarily slow

Wouldn't this entirely depend on selection pressure, rate of mutation, and turnover of, er, subjects? Certainly bacteria can evolve extremely rapidly and it's been noted in animals too, cf http://discovermagazine.com/2015/march/19-life-in-the-fast-l...

Didn't coffee only become a popular drink with westerners in the late 1800s or so?

Why? It's not exactly "survival of the fittest" but more like "survival of the good enoughs". If there is no pressure, it probably will not be improved.

Nature optimized them for hunting and gathering. I don't know about you, but I don't do much of that these days.

Biochemistry doesn't interact with higher cognitive function, and its very common to describe tasks like software bug hunting, or sitting in a loud open office grinding out boring code monkey stuff like very light agricultural work.

Certainly for the average office drone today, spear chucking muscles are atrophied, yet the thrill mood of hunting down and eliminating software bugs remains, pattern matching previous hunts, soaking in the environment, looking for signs, tracking, going in for the kill, the happy drudgery of dragging the kill back to the tribe or the paperwork of closing the bug out in the tribe's bug tracker and doing some git merges. Or tapping out calm tranquilized grind of endless lines of boilerplate java code feels like harvesting endless rows of cultivated berries. I wouldn't say the mood of labor has changed very much in some millennia, although the exact ratios of who's permitted the thrill of the hunt has varied over economic eras.

Sure, there are analogies between the two. But they're also different in meaningful ways, and evolution has not optimized us for their differences, which refutes the notion that we shouldn't mess with our biochemistry because we are perfectly evolved for the modern world. We're not.

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