["Studies of ethanol's effects on TSH carried out during the daytime, when its secretion is at its nadir, do not reflect the true action of alcohol on TSH secretion since TSH peak occurs at night.", 'The present study investigated the effects of alcohol on the serum concentrations of TSH in healthy volunteers during a 26-h session.', 'The trial included a 26-h session during which alcohol was administered at a rate similar to that found in heavy drinkers, i.e. 256 g per day and a 26-h placebo session. Volunteers functioned as their own controls, and we controlled for masking effects in both sessions.', 'The usual TSH circadian rhythm flattened during the alcohol session, and the usual peak in the middle of the night completely disappeared.'] Does alcohol decrease the nocturnal peak of TSH in healthy volunteers?