by What Melatonin Actually Does
Melatonin is a hormone produced by the pineal gland in response to darkness. It doesn't cause sleep directly — it's a timing signal that tells your brain and body "it's getting dark, start preparing for sleep." Rising melatonin triggers the cascade of physiological changes that precede sleep: lowered body temperature, reduced alertness, and decreased cortisol.
This distinction is critical for understanding why melatonin supplementation often disappoints: people expect a sleeping pill effect (you take it and get sleepy), but melatonin is a clock signal, not a sedative. It shifts when sleep naturally occurs, not how quickly you fall asleep in any given moment.
The Dosing Problem: Most People Take Too Much
The US has no regulatory cap on melatonin doses — products are sold at 1mg, 5mg, 10mg, and even 20mg. The research is clear: higher doses are not more effective and may be counterproductive.
- Natural peak melatonin during sleep: 0.1-0.3mg (100-300 micrograms)
- Effective supplemental dose: 0.1-0.5mg for adults
- Maximum therapeutic dose in most studies: 1-3mg
- Common OTC doses: 5-10mg (10-100x above physiologically necessary)
High doses (5-10mg) cause side effects including morning grogginess, headaches, dizziness, and can disrupt natural melatonin production. They may also cause the circadian shift to overshoot, causing early morning waking (3-4am) rather than the desired extended sleep.
Optimal Timing Protocol
- Dim bedroom and common area lights 1-2 hours before target bedtime (reduces light-induced melatonin suppression)
- Take 0.5mg melatonin 30-60 minutes before target bedtime
- Stay in dim light — avoid bright screens or overhead lights after taking melatonin
- Go to bed at the same time each night
When Melatonin Works Best
Jet Lag
The most evidence-backed use of melatonin. Take 0.5-1mg at the target bedtime of your new time zone starting the night of travel. This shifts the circadian clock to align with the new time zone 1-2 days faster than without supplementation. Cross multiple time zones (3+) benefit most; smaller shifts often adapt without supplementation.
Shift Work
Shift workers can use melatonin to facilitate sleep at unusual hours. 0.5-1mg 30 minutes before your designated sleep time (regardless of time of day) can help signal sleep initiation when the circadian clock hasn't yet aligned with the schedule. Combined with blackout curtains and a consistent sleep environment, melatonin meaningfully improves shift worker sleep quality.
Delayed Sleep Phase
People with Delayed Sleep Phase Syndrome (DSPS) — natural night owls who can't fall asleep until 2-4am — can use melatonin to shift their circadian clock earlier. Take 0.5mg in late afternoon (5-7pm) to begin the clock-shifting process. This is the most effective application of melatonin for chronic sleep problems.
What Melatonin Doesn't Fix
- Anxiety-driven insomnia — addresses timing, not arousal
- Pain-related sleep disruption — addresses timing, not pain
- Sleep maintenance problems (staying asleep) — primarily affects sleep onset, not maintenance
- General poor sleep hygiene — not a substitute for sleep habit improvements
Forms and Quality
Melatonin quality varies significantly between brands. A 2017 study found that melatonin content in supplements ranged from 83% less to 478% more than the labeled amount. Choose brands that have undergone third-party testing (NSF International, USP, or Informed Sport certification). Gummies often have more variable dosing than tablets or capsules.
FAQ
What is the correct dose of melatonin for sleep?
Most people take far too much melatonin. Research shows that 0.1-0.5mg is physiologically sufficient — the brain's natural melatonin peak is about 0.1-0.3mg. Over-the-counter doses of 5-10mg are 10-100x higher than necessary and can cause morning grogginess and headaches. Start with 0.5mg. Melatonin is a timing signal, not a sedative.
When should you take melatonin for sleep?
Take melatonin 30-60 minutes before your target bedtime, in dim light. Timing is the most important factor — melatonin signals 'it's getting late,' shifting your circadian clock toward sleep. Taking it with lights on reduces effectiveness because bright light suppresses melatonin signaling.
Is it safe to take melatonin every night?
Melatonin is generally considered safe for short-term use (weeks to months). Long-term nightly use is less studied — there's no strong evidence of harm but also no robust data on 5-10+ year continuous use. For chronic insomnia, behavioral interventions (CBT-I) are preferred over long-term melatonin use.
Who does melatonin work best for?
Melatonin is most effective for: circadian rhythm disruptions (jet lag, shift work, delayed sleep phase syndrome), people who need to fall asleep earlier than their natural timing, and older adults whose natural melatonin production has decreased. It's less effective for anxiety-driven insomnia or pain-related sleep disruption where the problem isn't circadian timing.