How Much Melatonin Should You Take? What to Know Before You Reach for the Bottle

What does melatonin actually do in the body?

Melatonin is a hormone your pineal gland releases naturally as darkness falls. It signals your body to prepare for sleep — it does not force sleep the way a sedative does. Supplemental melatonin mimics that signal. Because it works on timing rather than sedation, it is most useful when your internal clock is out of sync with when you want or need to sleep. It is not a strong sleeping pill, and taking more of it does not produce proportionally more effect.

Why do sleep medicine experts recommend starting with a lower dose?

Sleep medicine guidance generally notes that smaller doses are sufficient for most adults to get the timing benefit without overshooting the body's natural hormone range. A randomized trial found that as little as 0.5 mg of fast-release melatonin taken one hour before the desired bedtime advanced sleep onset meaningfully compared with placebo 3Ref 3Sletten TL, Magee M, Murray JM, et al. (2018).Efficacy of Melatonin with Behavioural Sleep-Wake Scheduling for Delayed Sleep-Wake Phase Disorder: A Double-Blind, Randomised Clinical Trial.0.5 mg fast-release melatonin taken 1 hour before desired bedtime advanced sleep onset by 34 minutes versus placebo — supports low-dose effectiveness over higher doses. Many over-the-counter products are packaged at doses that are higher than what researchers typically use in clinical studies. Starting low and assessing whether it helps before increasing is a widely supported approach.

Taking too much melatonin can cause next-day grogginess, vivid dreams, and headaches — signs that the dose exceeded what your body needed. A pharmacist is a good free resource for this conversation before you start.

Does timing matter as much as dose?

Yes — often more so. For general sleep-onset help, taking melatonin 30 to 60 minutes before the time you want to fall asleep is the standard recommendation. For jet lag, the timing strategy differs and depends on the direction of travel 1Ref 1Herxheimer A, Petrie KJ (2002).Melatonin for the Prevention and Treatment of Jet Lag.Melatonin's role in jet lag; timing strategy varies by direction of travel. For shift work, an entirely different protocol applies. If you are unsure which situation fits you, a clinician can help determine the right approach.

If you are taking melatonin at an inconsistent time each night, the benefit will be limited regardless of dose.

When is melatonin probably not the right tool?

Melatonin is a timing agent. If your problem is staying asleep through the night rather than falling asleep, it is unlikely to help much. If you feel tired all day despite sleeping a reasonable number of hours, or if a partner reports snoring, gasping, or limb movements, the root issue may be a sleep disorder — and melatonin will not address that 2Ref 2Kapur VK, Auckley DH, Chowdhuri S, et al. (2017).Clinical Practice Guideline for Diagnostic Testing for Adult Obstructive Sleep Apnea: An American Academy of Sleep Medicine Clinical Practice Guideline.Sleep apnea as a cause of unrefreshing sleep that melatonin will not address; clinical evaluation is needed.

For children and teenagers, dosing and appropriateness differ significantly from adults. Always involve a pediatrician before using melatonin in a child — long-term use in children has not been well studied.

Are there medication interactions or groups who should check first?

Melatonin can interact with blood thinners, diabetes medications, immunosuppressants, and certain other drugs. If you take any prescription medications or have a chronic health condition, ask your clinician or pharmacist before starting melatonin. Pregnant and breastfeeding individuals should check with their OB first, as safety data is limited. Older adults may metabolize melatonin more slowly, raising the risk of next-day grogginess even at standard doses.