A recent review of melatonin and sleep (PMID: 28460563) concluded that “Exogenous melatonin supplementation is well tolerated and has no obvious short- or long-term adverse effects.” Another recent article suggests, based on animal studies, that melatonin supplements “may be beneficial in the management of behavioural manifestations of drug addiction” (PMID: 29988891). Melatonin’s precursor tryptophan, like melatonin, is treated as a drug in some countries and sold over the counter in others. These differences are possible related to cultural factors that influence how a government balances the right of people to take whatever they want against the role of governments in protecting the population from possible harms associated with a compound.

Dear Simon, Thank you so much.