I’ve been researching the tryptophan metabolite 5-hydroxy-L-tryptophan (5-HTP) because of its use in alleviating depression, anxiety, insomnia and migraines. My dad found a book review that has quite a bit of information on its history, some of which I’ll relate here.
Napping after turkey dinners … that’s how many of us hear about tryptophan, an essential amino acid that purportedly produces relaxation and drowsiness. Tryptophan not only converts into niacin, but it serves as a precursor for serotonin. In the early 1970s, it gained popularity as an over-the-counter supplement for its sleep-enhancing properties, among other beneficial side-effects.
Yet a company’s two contaminated batches of tryptophan in 1989 caused an epidemic of eosinophilia myalgia syndrome, thus prompting the FDA’s ban of tryptophan – at first temporarily, merely to investigate the causes of the epidemic, and then permanently.
So when the first selective serotonin reuptake inhibitors (SSRI), Prozac, came on the market, it had no competition. Prozac intentionally interfered with the recycling of serotonin (hence “reuptake inhibitors”) and as a result depleted cellular stores of serotonin. Tryptophan, on the other hand, increases the stores of serotonin.
5-HTP was allowed to enter the over-the-counter market in 1994 as an unrestricted dietary supplement due to Congress’ Dietary Supplement Health and Education Act. Tryptophan, although much milder and its impact on the body more researched, is still prohibited.