What Is Melatonin?
Melatonin is a hormone produced naturally by the pineal gland in response to darkness. It signals to your brain that it is time to sleep, helping to regulate the circadian rhythm. As a supplement, it is used for insomnia, jet lag, and circadian rhythm disorders. In the United States, melatonin is classified as a dietary supplement and is not FDA‑regulated as a drug, which means quality and potency can vary between brands. When used correctly — at the right dose and at the right time — melatonin can be a safe and effective aid for sleep.
| Time of Day | Melatonin Level | Effect |
|---|---|---|
| Morning | Very low | Promotes wakefulness |
| Evening (dusk) | Rising | Prepares body for sleep |
| Night (peak) | Highest (~2–4 a.m.) | Maintains sleep |
| Late night | Declining | Prepares for waking |
How Much Should You Take?
The question "how much melatonin should I take" is best answered by starting low and going slow. Clinical studies show that doses as low as 0.5 mg can be effective for many people, and that higher doses (3–5 mg or more) often cause more side effects without being more effective. A melatonin dosage calculator like this one uses your body weight and age to recommend a starting dose. For most adults, 0.5–1 mg taken 30–60 minutes before bed is a good starting point. If you don't notice an improvement after a week, you can gradually increase up to 3 mg. Doses above 5 mg are rarely necessary. Melatonin by weight is not an exact science, but as a general guide: lighter individuals tend to respond to lower doses, while heavier individuals may need slightly more. The table below shows typical starting doses.
| Body Weight (lbs) | Starting Dose (mg) | Max Recommended (mg) |
|---|---|---|
| 90–130 | 0.5 | 1.5 |
| 130–180 | 0.5–1 | 3 |
| 180–230 | 1–1.5 | 3 |
| 230+ | 1.5–2 | 5 |
Timing It Right
Melatonin timing for sleep is just as important as the dose. If you are using melatonin to help you fall asleep, take it 30–60 minutes before your target bedtime. Taking it too early may cause drowsiness before you're ready for sleep; taking it too late may leave you feeling groggy the next morning. For circadian rhythm shifts — such as jet lag or adjusting to a new schedule — the timing is more critical. For eastward travel (which requires advancing your clock), take melatonin about 30 minutes before your desired bedtime at the destination. For phase‑advance protocols (e.g., treating delayed sleep phase syndrome), a very small dose (0.5 mg) taken 4–6 hours before your desired bedtime can be more effective. Always start with the lowest effective dose.
| Goal | When to Take | Dose |
|---|---|---|
| Falling asleep | 30–60 min before bedtime | 0.5–3 mg |
| Jet lag (eastward) | 30 min before local bedtime | 0.5–3 mg |
| Phase advance (DSPS) | 4–6 hours before desired bedtime | 0.5 mg |
Melatonin for Jet Lag
Melatonin for jet lag dosage typically falls in the 0.5–3 mg range, taken at the local bedtime of your destination for the first 3–4 nights after arrival. It is most effective for eastward travel across 5 or more time zones. Combined with timed light exposure, it can significantly reduce jet lag symptoms. Avoid taking melatonin during the day at your destination, as this can confuse your circadian clock.
Melatonin for Shift Work
If you are a night shift worker trying to sleep during the day, melatonin can help signal to your brain that it is nighttime. Take 0.5–3 mg about 30 minutes before your planned daytime sleep. Combine it with a dark, cool sleep environment and light management strategies (bright light during the first half of your shift, sunglasses on the commute home). Melatonin is not a sedative and will not override a strong circadian wake signal, so it works best as part of a comprehensive shift work sleep plan.
Side Effects and Safety
Melatonin is generally well‑tolerated at low doses. Common side effects include headache, dizziness, and daytime drowsiness — especially if the dose is too high or taken at the wrong time. Some people report vivid dreams. Because melatonin is a hormone, there are theoretical concerns about long‑term use, though studies up to several months have not shown significant risks. Melatonin 3 mg vs 5 mg — higher doses are not more effective for most people and increase the likelihood of next‑day grogginess. Melatonin can interact with blood thinners, immunosuppressants, and diabetes medications. It is not recommended for children unless under the guidance of a pediatrician. In many countries, melatonin is available only by prescription. Always choose a product that has been third‑party tested (look for USP or NSF certification) to ensure quality. Consult a healthcare provider before starting melatonin, especially if you are pregnant, breastfeeding, or taking other medications.
| Population | Recommendation |
|---|---|
| Adults | 0.5–3 mg, 30‑60 min before bed; generally safe |
| Children | Only under pediatrician guidance |
| Pregnancy / Breastfeeding | Avoid; not enough safety data |
| Autoimmune disorders | Consult physician; may stimulate immune system |
| On blood thinners | Consult physician; possible interaction |
Frequently Asked Questions
- Buscemi, N., et al. (2005). The efficacy and safety of exogenous melatonin for primary sleep disorders. Journal of General Internal Medicine.
- Ferracioli‑Oda, E., et al. (2013). Meta‑analysis: melatonin for the treatment of primary sleep disorders. PLOS ONE.
- AASM. (2017). Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults.
- NIH National Center for Complementary and Integrative Health. (2024). Melatonin: What You Need To Know.