Most melatonin supplements recommend taking the product about 20 to 60 minutes before bedtime, but taking it earlier might be more effective.

A recent review in the Journal of Pineal Research suggests that taking two to four milligrams of melatonin three hours before your desired bedtime would enhance its sleep-promoting effects.

“Naturally occurring melatonin levels rise about two hours before bedtime, and this may be why the earlier dosing that coincides with the natural melatonin spike is important,” Thomas Michael Kilkenny, DO, director of the Institute of Sleep Medicine at Northwell Staten Island University Hospital, told Verywell in an email.

Kilkenny added that melatonin provides only temporary relief for people with sleep issues. Those with chronic insomnia—having trouble sleeping at least three times a week for three months—are unlikely to benefit from melatonin.

“A good approach is to try to discover the underlying issues and work on it, but we can use melatonin as an assist, but not a cure for the insomnia,” Kilkenny said.

Who Should Take Melatonin Earlier?

Melatonin may benefit shift workers, people with jet lag disorder, or those who experience short-term insomnia. People who develop insomnia during a hospital stay might need around mg of melatonin taken half an hour or less before their natural drowsy time, said Sudha Tallavajhula, MD, a sleep medicine physician at UTHealth Houston.

While the new review recommends moving this timing up, the findings indicate that melatonin is more effective in healthy people who don’t have insomnia.

“I don’t think that this study by itself is evidence enough to say that patients with insomnia should be taking it ahead of time, because they are actually suggesting that it works better in patients without insomnia,” she added.

Are Melatonin Supplements Safe?

Short-term use of melatonin appears safe, but the long-term effects, especially in high doses, are still unknown.

Some people may experience nausea, dizziness, headaches, and daytime drowsiness when taking this supplement. Melatonin can also interact with certain medications, like warfarin and antiseizure drugs, so it’s best to consult a healthcare provider before starting the supplement.

The Food and Drug Administration (FDA) does not regulate supplements, including melatonin, for safety or efficacy before they hit store shelves. Researchers have found that many products contain 74% to 347% more melatonin than what’s stated on the label. They might also be contaminated with pesticides, heavy metals, and unlisted ingredients.

People who experience mild insomnia every once in a while might benefit from trying dietary sources of melatonin instead, according to Tallavajhula. 

Food sources like mushrooms, eggs, fish, nuts, and cherries contain natural melatonin. Tart cherry juice is also rich in melatonin, but more research is needed to understand the effect and appropriate timing of dietary melatonin sources.