That is, it is a substance capable of therapeutically entraining or re-entraining long-term desynchronized or short-term dissociated circadian rhythms in mammals, or prophylactically preventing their disruption following an environmental insult such as is caused by rapid travel across several time zones.
Mark Altschule and Julian Kitay, both physicians at Harvard, summarized the body of pineal gland literature in the 1950s.
[5][6] Melatonin was originally discovered by Aaron Lerner, a Yale dermatologist, and colleagues, who had hoped it could be used to treat vitiligo.
Although melatonin did not prove to be relevant to dermatology treatments, it was quickly confirmed to be secreted by the pineal gland to affect the brain.
[7] Robert Moore and David Klein first studied the SCN in the context of melatonin secretion by the pineal gland in 1974.
[10][11] The field of chrononutrition was established after dietary tryptophan was shown to synchronize the circadian rhythm with environmental time cues in 1968.