Is it safe to take melatonin on a regular basis?

Regular melatonin use—especially at high supplement doses—is generally not advised; it can help you fall asleep but may affect sleep continuity and other hormone systems. 1

• 1. Sleep continuity: Melatonin may help you fall asleep without helping you stay asleep; some people wake three to five hours later and have trouble returning to sleep. 2
• 2. Dose and product variability: Typical supplements can deliver doses far above the body’s normal production, and measured products have contained substantially less or more than their labels indicate. 3 4
• 3. Reproductive hormones and children: Melatonin can affect reproductive hormone signaling, including testosterone and estrogen; the discussion raises particular caution about regular use in children because melatonin may suppress puberty-related signaling. 5 6
• 4. Possible specific uses: Occasional use for jet lag may be reasonable, and supplementation may be considered for some older adults with sleep problems. For use, consult a physician or a clinician knowledgeable about sleep and circadian biology. 7 8 9

The overall concern is not simply whether melatonin is acutely dangerous, but that chronic use may bring uncertain hormone effects and inconsistent dosing. 10