The amplitude of endogenous melatonin production is not affected by melatonin treatment in humans

Matsumoto M, Sack RL, Blood ML, Lewy AJ. The amplitude of endogenous melatonin production is not affected by melatonin treatment in humans. J. Pineal Res. 1997; 22:42–44. © Munksgaard, Copenhagen Abstract A physiological dose of melatonin (0.5 mg) or placebo was given at bedtime to night shift workers (n=21) for seven days, and endogenous melatonin profiles were measured on the eighth day. The amplitude of endogenous melatonin secretion was unchanged by treatment. Also, a melatonin treatment trial using a 50 mg daily bedtime dose for 37 days to a blind subject resulted in no change in the endogenous melatonin profile. We conclude that circulating melatonin can shift the phase, but does not alter the amplitude, of pineal melatonin secretion.