Melatonin supplements may help you sleep in the short term, but their long-term safety and effectiveness are unknown. Prolonged use, for instance, may undermine the body’s ability to produce its own melatonin. Hormones are powerful substances that can produce unexpected results. In many countries, melatonin is sold only by prescription.
- Reported adverse effects, usually from long-term use, include high blood sugar, breast swelling in men, decreased sperm count, gastrointestinal irritation, sleepwalking and dizziness.
- Like other sleeping pills, melatonin can cause drowsiness the next day. That’s risky if you are driving or operating machinery.
- There’s no consensus about which doses, schedule and formulation of melatonin are best for various sleep disorders. The typical dose for insomnia is 1 to 5 milligrams.
- Melatonin is found in some foods, including cherries, rice, bananas and grapes— but it’s unclear how much these raise blood levels of melatonin. One small study found that tart cherry juice helped older people with insomnia sleep a little better than a placebo drink. The subjects drank 16 ounces a day, supplying about 250 calories—a lot of calories for a “modest” effect.
Our advice: If you take melatonin, do so only occasionally and short term. If you have a chronic disease, such as diabetes, liver or kidney disease, clinical depression or an immune disorder, consult your doctor before taking it.