Possible Interaction: Caffeine and Melatonin

“After administration of a caffeine and/or melatonin supplement, there was a significant increase in progressive motility in the CAF (p = 0.005) and CM (p = 0.048) groups, as well as mitochondrial activity in the CM group (p < 0.05).”

“RESULTS When ca feine wa s coadministered the Cmax and AUC of mel atonin we re increased on average by 142% (P = 0.001, confidence interval on the difference 44, 80%) and 120% (P < 0.001, confidence interval on the difference 63, 178%), respectively.”

“A 200-mg dose of caffeine also reduced melatonin levels, although to a lesser degree than 1 h exposure to 3000 lx.”

“ Caffeine reduced the onset of melatonin levels for women in the luteal phase, but it had little effect on melatonin levels for oral contraceptive users.”

“Combining caffeine ingestion with bright light exposure (> or = 2000 lux) suppressed melatonin and attenuated the normal nighttime drop in temperature to a larger degree than either condition alone; i.e. effects were additive.”

“We show that evening caffeine consumption delays the human circadian melatonin rhythm in vivo and that chronic application of caffeine lengthens the circadian period of molecular oscillations in vitro, primarily with an adenosine receptor/cyclic adenosine monophosphate (AMP)–dependent mechanism.”

“Abstinence from caffeine for 24 hr prior to melatonin intake should be enough to overcome the possible confounding effect of caffeine on the CYP1A2 phenotyping with melatonin.”

“Caffeine, co-administered 12 or 24 hr prior to melatonin intake, did not have any significant effect on ….5 hr melatonin concentration (P=0.086 for ANOVA), but in two volunteers about 4 times increase in melatonin concentration … after caffeine intake 12 hr (but not …) before phenotyping with melatonin.”

“However, caffeine inhibits the metabolism of melatonin by CYP1A2 and dietary caffeine could be a potential confounder for the measurement of CYP1A2 activity with melatonin.”

“ Melatonin secretion is reduced by alcohol, caffeine , and some commonly prescribed drugs.”

“Besides, changes in angiotensin receptor expression observed in response to a caffeine and melatonin exposure result from high dose and join effect.”

“In this study, we examined whether a combination of Coff or Caff plus Mel produced a synergistic/additive effect on amyloid-β (Aβ) generation in Neuro-2a (N2a)/amyloid precursor protein (APP) cells and the possible mechanisms involved.”