Health experts strongly recommend against combining melatonin and alcohol. Although both melatonin and alcohol are sedatives, the combined effects of the two may actually disrupt normal, healthy sleep, especially for alcoholics. Alcohol may increase the side effects of melatonin, especially drowsiness and headaches.

Melatonin is a chemical naturally produced by the pineal gland in humans and animals that signals the body it is time to sleep. People suffering from insomnia or jet lag may have improper levels of melatonin, causing sleeplessness. Melatonin supplements, available over the counter in the US or by prescription in some other countries, can help correct this imbalance and produce a sedative effect.

Alcohol is also classified as a depressant, but contrary to common wisdom, it may not actually improve the quality of sleep. After alcohol is ingested, the body responds to its sedative effects by producing adrenaline — a powerful natural stimulant. This may result in disrupted sleep, such as sleeping for an hour or two followed by one or more periods of wakefulness. Heavy alcohol use over a long period of time intensifies this effect and may disrupt the body's ability to produce melatonin. An alcoholic might be tempted to take melatonin supplements to compensate, but this is inadvisable.

When melatonin and alcohol are used together, the most common result is pronounced drowsiness. The patient may sleep fitfully for an extended period of time, experiencing periods of wakefulness in between vivid nightmares. A few patients have also reported feeling as though they had taken a stimulant. If the person does sleep through the night, he or she may wake up feeling "hung over," even if the amount of alcohol consumed would not normally have produced such an effect. The combined effect of melatonin and alcohol may also result in headaches, body aches, and dehydration.

While using melatonin and alcohol simultaneously is not recommended, some research indicates that taking melatonin supplements may ease some of the difficulties associated with alcohol withdrawal, especially insomnia. Other experts, however, say that dependence on melatonin supplements during withdrawal may prevent the body from re-learning to produce its own melatonin. Anyone with an alcohol dependence should seek medical advice about the best way to handle the effects of withdrawal.