SLEEP SCIENCE

Does Melatonin Cause Weight Gain or Help Weight Loss?

By WellnessVigor · Updated October 10, 2026 · 7 min read

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Melatonin is one of the most popular sleep supplements in the world. Online, you will find people saying it made them gain weight, and others claiming it helps burn fat. Which is true?

Here is what the evidence says about melatonin and weight, how to use it safely, and better ways to support sleep and weight loss together.

Quick answer

There is no good evidence that melatonin causes weight gain, and no strong evidence that it causes meaningful weight loss either. Any weight change people notice is more likely due to late-night snacking, grogginess and less activity, or changes in sleep. Melatonin is best for short-term problems like jet lag or a shifted sleep schedule, at a low dose.

What is melatonin?

Melatonin is a hormone your brain makes in the evening when it gets dark. It tells your body it is time to sleep. Supplements are used to help with jet lag, shift work and delayed sleep schedules. The US National Center for Complementary and Integrative Health (NCCIH) says melatonin may help with jet lag and some sleep timing problems, with smaller benefits for general insomnia.

Does melatonin cause weight gain?

Research does not show that melatonin directly causes weight gain. If you notice weight gain while taking it, consider other factors:

  • Late-night eating: taking melatonin and then staying up and snacking.
  • Morning grogginess: taking too high a dose or too late can leave you sluggish and less active.
  • Other medicines or conditions that cause both sleep problems and weight gain.
  • Gummies: some melatonin gummies contain sugar, though the amount per serving is small.

Can melatonin help you lose weight?

Some small studies suggest melatonin might have modest effects on metabolism or body composition, but results are mixed and not strong enough to recommend it for weight loss. The more reliable link is indirect: better sleep supports appetite control. See can poor sleep make you gain weight?

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How to use melatonin safely

  • Start low: many experts suggest 0.5 to 3 mg; more is not always better.
  • Timing matters: take it 1 to 2 hours before your target bedtime, or as advised for jet lag.
  • Use it short term unless your doctor advises otherwise; long-term safety is not well studied.
  • Choose tested products. A 2023 study in JAMA found that 22 of 25 melatonin gummy products were mislabelled, with actual melatonin ranging from 74% to 347% of the label. Look for a third-party mark such as USP Verified.
  • Possible side effects: headache, dizziness, nausea and daytime sleepiness.
  • Check with a doctor if you are pregnant, breastfeeding, take blood thinners, epilepsy medicines, blood pressure or diabetes medicines, or have an autoimmune condition. Keep it away from children.

A third-party tested option

If you and your doctor decide melatonin is right for you, choose a low-dose, third-party verified product.

BEST WIDELY AVAILABLE VERIFIED BRAND

Nature Made Melatonin (Low Dose)

A widely sold brand that offers low-dose melatonin tablets. Check the label for the USP Verified mark on the specific product you choose.

Pros

  • Low-dose options
  • Widely available
  • Simple tablets

Cons

  • Not for long-term use without advice
  • Not suitable for everyone
Check price on Amazon

Natural ways to boost melatonin

  • Get bright daylight in the morning.
  • Dim lights and screens 1 to 2 hours before bed.
  • Keep the bedroom dark and cool.
  • Eat foods that naturally contain melatonin, like tart cherries, oats and walnuts. See healthy late-night snacks.

Keep reading

Frequently asked questions

Does melatonin make you hungry?

There is no strong evidence that melatonin increases appetite. Staying up late after taking it, however, can lead to snacking.

Is it safe to take melatonin every night?

Short-term use appears safe for most adults. Long-term nightly use has not been well studied, so talk to your doctor.

What is the best dose of melatonin?

Many experts suggest starting with 0.5 to 3 mg. Higher doses are not necessarily more effective and may cause grogginess.

Can melatonin help with weight loss?

Evidence is weak and mixed. Better sleep supports weight control, but melatonin is not a weight loss supplement.

Sources

  1. NCCIH: Melatonin: what you need to know
  2. Cohen PA, et al. Quantity of melatonin and CBD in melatonin gummies sold in the US. JAMA, 2023.
  3. Mayo Clinic: Is melatonin a helpful sleep aid?

This article is for general information only and is not medical advice. See our Medical Disclaimer.

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