Somewhere along the way, melatonin became America's over-the-counter sleeping pill. Sales in the US hit $1.09 billion in 2021 — a 150% jump from 2016. Parents give it to kids. Adults take 10 mg gummies like they're candy. And most of them are using it wrong.

Melatonin is not a sedative. It doesn't knock you unconscious like Ambien or Benadryl. It's a hormone — specifically, a chronobiotic — that signals to your brain that darkness has arrived and it's time to prepare for sleep. The distinction matters enormously, because if you misunderstand what melatonin does, you'll misuse it, get disappointed, and either take more (still wrong) or give up entirely.

What Melatonin Actually Does

Your pineal gland produces melatonin in response to darkness. As light fades in the evening, melatonin secretion rises, peaking between 2 and 4 a.m., then declining toward morning. This rhythm is your circadian clock's primary output signal for sleep timing.

Melatonin doesn't make you sleep. It opens the "sleep gate" — it signals to your suprachiasmatic nucleus (the brain's master clock) that conditions are right for sleep onset. If you're wired on caffeine, stressed about tomorrow's meeting, or staring at a blue-light screen, melatonin alone won't override those signals.

A meta-analysis in PLOS ONE (2013) — analyzing 19 randomized controlled trials with 1,683 participants — found that melatonin supplementation reduced sleep onset latency (time to fall asleep) by an average of 7 minutes, increased total sleep time by 8 minutes, and improved overall sleep quality. These are statistically significant but modest effects. This is not a drug that puts you to sleep. It's a hormone that nudges your timing.

The Dose Problem: Less Is More

This is the biggest misunderstanding in the melatonin world.

Your pineal gland produces about 0.1-0.3 mg of melatonin per night. The physiological dose — the amount that mimics your body's natural production — is 0.3-0.5 mg.

Most commercial melatonin supplements start at 3 mg. Many are 5 mg. Some are 10 mg. A few are 20 mg. These are 10 to 60 times your body's natural production.

At supraphysiological doses, several problems emerge:

  • Desensitization. Chronically high melatonin levels may downregulate melatonin receptors (MT1 and MT2), potentially making the supplement less effective over time.
  • Next-day grogginess. Melatonin has a half-life of 40-60 minutes, but at high doses, residual levels can persist into the morning, causing the "melatonin hangover" — grogginess, sluggishness, and difficulty waking.
  • Phase-shifting gone wrong. High doses can shift your circadian rhythm in unintended directions, particularly if timing is off.

A study from MIT, published in the Journal of Pineal Research (2001), found that 0.3 mg of melatonin was just as effective as 3 mg for improving sleep — without the side effects. Lead researcher Richard Wurtman, who holds the patent on melatonin's use as a sleep aid, has repeatedly stated that commercial doses are far too high.

Start at 0.3-0.5 mg. If that doesn't work, try 1 mg. Going above 3 mg is almost never necessary and usually counterproductive.

Timing: When You Take It Matters More Than How Much

For standard sleep onset support, take melatonin 30-60 minutes before your desired bedtime.

For circadian rhythm disorders — the conditions melatonin is actually best at treating — timing is more specific:

Delayed sleep-wake phase disorder (DSWPD): Your clock runs late — you can't fall asleep until 2-3 a.m. and can't wake before 10-11 a.m. Take 0.5-1 mg of melatonin 4-6 hours before your desired sleep time. This advances your circadian phase earlier.

Jet lag (eastward travel): Take 0.5-3 mg at the destination's bedtime for 3-5 nights after arrival. Eastward travel requires advancing your clock, which melatonin handles well.

Jet lag (westward travel): Usually less disruptive. If needed, take melatonin at destination bedtime, but you may not need it — your body naturally delays more easily than it advances.

Shift work: Melatonin can help day sleepers (night shift workers) fall asleep during daylight hours. Take 1-3 mg when you want to sleep, combined with blackout curtains and light avoidance.

Where Melatonin Shines

Circadian rhythm disorders are melatonin's strongest indication. The American Academy of Sleep Medicine (AASM) recommends melatonin for delayed sleep-wake phase disorder and for jet lag, particularly for eastward travel across multiple time zones.

Older adults. Melatonin production declines with age. By 60-70, nocturnal melatonin levels may be 50% lower than in young adults. Low-dose supplementation (0.5-1 mg) can help restore the circadian signal that dims with aging.

Children with neurodevelopmental conditions. Melatonin has the strongest pediatric evidence in children with ADHD and autism spectrum disorder, where sleep onset insomnia is extremely common. A Cochrane review confirmed that melatonin improves sleep latency and duration in these populations. However, the long-term safety of melatonin in children is still being studied.

Where Melatonin Falls Short

Sleep maintenance insomnia. If your problem is waking at 3 a.m. and not being able to fall back asleep, standard immediate-release melatonin won't help much — it's already cleared your system by then. Extended-release formulations may provide some benefit, but the evidence is limited.

Insomnia driven by anxiety, pain, or medical conditions. Melatonin doesn't address the root cause. If your mind is racing with worry or your back is screaming, a chronobiotic won't fix it.

Chronic insomnia disorder. The AASM's clinical practice guidelines actually recommend against melatonin for chronic insomnia in adults, citing insufficient evidence. Cognitive behavioral therapy for insomnia (CBT-I) remains the first-line treatment.

Quality Control: A Real Concern

Melatonin is sold as a dietary supplement in the US, which means it isn't subject to the same purity and potency standards as pharmaceuticals.

A study in the Journal of Clinical Sleep Medicine (2017) tested 31 melatonin supplements and found that actual melatonin content varied from 83% less to 478% more than what the label claimed. That's not a typo — some products contained nearly five times the stated dose. Even more concerning, 26% of the supplements also contained serotonin, a controlled substance not listed on the label.

Buy from brands that carry third-party certifications (USP, NSF, or ConsumerLab verification). This is one supplement where what's in the bottle matters as much as what's on the label.

Safety and Side Effects

Melatonin is generally safe for short-to-medium-term use. Common side effects at higher doses include:

  • Morning grogginess
  • Vivid dreams or nightmares
  • Mild headache
  • Dizziness
  • Short-term feelings of depression (rare)

Melatonin can interact with:

  • Blood thinners (may increase bleeding risk)
  • Immunosuppressants (melatonin stimulates immune function)
  • Diabetes medications (may affect blood sugar)
  • Contraceptive pills (may increase melatonin levels)

When to Talk to a Pro

See a sleep specialist or healthcare provider if:

  • You've been taking melatonin nightly for more than 4 weeks without improvement
  • Your insomnia is accompanied by snoring, gasping, or daytime sleepiness (rule out sleep apnea)
  • You're using melatonin to manage a child's sleep — discuss appropriate dosing and duration
  • You take medications that may interact with melatonin
  • You suspect a circadian rhythm disorder (a sleep specialist can confirm with actigraphy or questionnaires)

FAQ

Is melatonin safe for children? Short-term use appears safe in pediatric populations, particularly for children with ADHD or autism. However, melatonin is a hormone, and its effects on pubertal development with long-term use are not fully understood. Always use the lowest effective dose and consult a pediatrician.

Can you become dependent on melatonin? Melatonin is not addictive and does not produce physical dependence or withdrawal symptoms. However, some people develop a psychological reliance — they feel they "can't sleep without it" even though the physiological need for supplementation may not exist. Periodic reassessment is wise.

Why does melatonin give me vivid dreams? Melatonin may increase time spent in REM sleep, the stage associated with vivid dreaming. Higher doses are more likely to cause this effect. Lowering your dose often resolves it.

Is melatonin banned in other countries? In many European countries, Australia, and parts of Asia, melatonin is available only by prescription. This isn't because it's dangerous — it reflects a philosophical difference in how hormones are regulated. The US is an outlier in allowing over-the-counter access.

A note from Living & Health: We're a lifestyle and wellness magazine, not a doctor's office. The information here is for general education and entertainment — not medical advice. Always talk to a qualified healthcare professional before making changes to your health routine, especially if you have existing conditions or take medications.