Melatonin for Sleep: The Right Dose and When to Take It

Melatonin is the most popular sleep supplement in the world — and most people take it wrong. The standard dose sold in pharmacies (5-10mg) is far higher than what research shows to be effective, and timing matters as much as dose. Here's what the evidence actually supports.

What Melatonin Actually Does

Melatonin is a hormone produced by the pineal gland that signals to the body that it's time to sleep. It doesn't knock you out like a sedative — instead it shifts your internal clock and reduces alertness in preparation for sleep. The distinction matters: melatonin is a sleep-timing hormone, not a sleep-forcing drug.

This means it's most effective for conditions related to circadian rhythm disruption — jet lag, shift work, delayed sleep phase syndrome — and less effective for general insomnia caused by anxiety, pain, or sleep hygiene issues.

The Dose Problem

Research consistently shows that 0.5-1mg is as effective as 5-10mg for improving sleep onset, with fewer side effects. The pharmaceutical doses sold over the counter (5mg, 10mg) are physiologically supraphysiological — far beyond what the body produces naturally. High doses can cause morning grogginess, headaches, and may paradoxically disrupt sleep architecture over time.

Start with 0.5mg. If ineffective after a week, try 1mg. Most people see no additional benefit beyond 1-3mg.

Timing Is Critical

Melatonin works best when taken 30-60 minutes before your desired bedtime, not your actual bedtime. Taking it too close to when you want to fall asleep reduces its effectiveness.

For jet lag travelling east: take it at the destination's bedtime for 2-3 nights. For delayed sleep phase (night owl who can't fall asleep until late): take a small dose 5-6 hours before your desired sleep time to gradually shift your clock earlier.

When Melatonin Doesn't Help

Melatonin is unlikely to help if your insomnia is driven by anxiety, stress, a noisy environment, or poor sleep habits (late screens, irregular schedule, alcohol before bed). Address those factors first. It's also not designed for long-term use as a sleep aid — Cognitive Behavioural Therapy for Insomnia (CBT-I) has the strongest evidence for chronic insomnia.

Quality Concerns

A 2017 study tested 31 melatonin supplements and found the actual melatonin content varied from 83% less to 478% more than the label claimed. Choose brands that are third-party tested and certified. Extended-release formulations may help if you wake during the night rather than having trouble falling asleep.

Melatonin is generally safe for short-term use. Avoid in pregnancy. May interact with blood thinners and immunosuppressants.