Cherries, Gogi berries, eggs, milk, fish, and nuts are all dietary sources of melatonin. That might be something to try without exposing yourself to extensively processed and refined products.
Correction for the article: melatonin is available without a prescription in Canada (or at least Ontario) and in France. I know from personal experience. In the UK, however, I was surprised to see it required a prescription. I can’t speak for the other territories on the list, but I think the whole article might need a fact-check as a result. :)
More than a quarter of products sampled were contaminated with seratonin: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5263069/
Of 25 products sampled 22 were mislabled: https://www.nytimes.com/2023/04/25/well/live/melatonin-gummi...
Cherries, Gogi berries, eggs, milk, fish, and nuts are all dietary sources of melatonin. That might be something to try without exposing yourself to extensively processed and refined products.