Melatonin Dosage: How Much Should You Actually Take?

Most people take too much melatonin. The standard 5-10mg doses sold in pharmacies are 5-20 times higher than what research shows is effective — and higher doses often produce worse results, including next-day grogginess, hormonal disruption, and reduced effectiveness over time. Here is what the science actually says about melatonin dosage.

The Dosage Problem

Why less is more with melatonin

Melatonin is a hormone, not a sedative. It does not knock you out — it signals your brain that it is nighttime, triggering the cascade of physiological changes that prepare the body for sleep. The dose required to produce this signal is far lower than what most supplements contain.

A landmark study by MIT researcher Richard Wurtman found that 0.3mg of melatonin was as effective as 1mg and 10mg for improving sleep onset — and produced more natural sleep architecture. Higher doses saturate melatonin receptors without additional benefit, while causing next-day grogginess and potentially suppressing the body's own melatonin production over time.

What the research says

The most comprehensive meta-analysis on melatonin dosage (Brzezinski et al., 2005) found that doses between 0.1mg and 0.5mg were effective for shifting circadian timing and improving sleep onset. A 2022 review in the Journal of Pineal Research confirmed that physiological doses (0.1-0.5mg) are more effective than pharmacological doses (5-10mg) for most sleep applications.

The reason most supplements contain 5-10mg is not because that dose is more effective — it is because higher doses are easier to manufacture and market. The effective dose is so small that it is difficult to produce accurately at scale.

Dosage by Use Case

For sleep onset (difficulty falling asleep)

Dose: 0.5-1mg
Timing: 30-60 minutes before desired sleep time
Notes: This is the most common use case. Start at 0.5mg and increase to 1mg only if needed. Higher doses (3-10mg) are not more effective and increase side effect risk.

For jet lag

Dose: 0.5-3mg
Timing: At the target destination's bedtime on the day of arrival
Notes: Melatonin is most effective for jet lag when traveling east (advancing the clock). For westward travel, it is less effective. Take for 2-5 days after arrival. Light exposure at the destination is equally important.

For circadian rhythm shifting (night owls)

Dose: 0.5mg
Timing: 5-6 hours before your current natural sleep time (not at bedtime)
Notes: This is the most evidence-based use of melatonin for night owls. Taking it at bedtime does not shift the circadian clock — it must be taken earlier in the evening to advance the phase. This is called the "phase advance" protocol.

For shift workers

Dose: 1-3mg
Timing: At the desired sleep time (which varies with shift schedule)
Notes: Melatonin helps shift workers sleep during the day by signaling nighttime to the brain. Combine with blackout curtains and consistent timing for best results.

For children (with medical guidance)

Dose: 0.5-1mg (always consult a pediatrician first)
Timing: 30-60 minutes before bedtime
Notes: Melatonin is sometimes used for children with autism spectrum disorder or ADHD who have significant sleep difficulties. It should not be used routinely in healthy children without medical guidance, as long-term effects on development are not fully established.

Timing: The Most Important Variable

Why timing matters more than dose

Melatonin's effectiveness depends more on when you take it than how much you take. Taking melatonin at the wrong time can actually delay sleep rather than advance it. The key principle: melatonin should be taken when your body's natural melatonin is low — typically in the early evening for most people.

Taking melatonin at 10 PM when your natural melatonin is already rising (because you are a normal chronotype going to bed at 11 PM) adds little benefit. Taking it at 7-8 PM when melatonin is still low can advance your sleep timing by 1-2 hours over several days.

The dim light melatonin onset (DLMO)

Your natural melatonin begins rising approximately 2 hours before your habitual sleep time — this is called the Dim Light Melatonin Onset (DLMO). For most people, this is around 9-10 PM. Taking supplemental melatonin 1-2 hours before DLMO (around 7-8 PM for most people) is the most effective timing for advancing sleep phase.

Side Effects and Safety

Short-term side effects

At low doses (0.5-1mg), side effects are minimal. At higher doses (5-10mg), common side effects include: next-day grogginess and cognitive impairment, headache, dizziness, nausea, and vivid or disturbing dreams. These are dose-dependent — reducing the dose typically eliminates them.

Long-term considerations

Melatonin is generally considered safe for short-term use (weeks to months). Long-term daily use raises questions about whether it suppresses the body's own melatonin production — the evidence is mixed, but this is a reasonable concern, particularly at high doses. If you need melatonin nightly for months, addressing the underlying sleep issue (circadian misalignment, sleep hygiene, insomnia) is preferable to indefinite supplementation.

Drug interactions

Melatonin can interact with blood thinners (warfarin), immunosuppressants, diabetes medications, and contraceptives. If you take any prescription medications, check with your doctor or pharmacist before starting melatonin.

Choosing a Quality Supplement

Melatonin supplement quality varies significantly. A 2017 study found that actual melatonin content in supplements ranged from 83% below to 478% above the labeled dose. Look for supplements that are third-party tested (NSF, USP, or Informed Sport certified). Liquid or sublingual forms allow more precise low-dose administration. Avoid products with unnecessary additives or proprietary blends.