Melatonin has become one of the most popular sleep aids in America. Use among adults rose sharply over the last two decades, and it is now sold as gummies, tablets, sprays, teas and even in kids' flavors. Yet many people who take it misunderstand what it does. Melatonin is not a sedative. It is a timing signal. Once you understand that, it becomes much easier to use it well, or to decide you do not need it.
What melatonin actually is
Melatonin is a hormone your brain makes in the evening as the light fades. It tells your body that night has come. Levels stay high during the night and fall in the morning. Bright light, especially in the evening, suppresses it. That is why screens and bright lights at night can make it harder to fall asleep.
In the United States, melatonin is sold as a dietary supplement. In many other countries, including the United Kingdom and much of Europe, it requires a prescription.
What it is good for
The National Center for Complementary and Integrative Health summarizes the research on its melatonin page. The evidence is strongest for:
- Jet lag. Melatonin can help reset your body clock when you cross several time zones, especially flying east.
- Delayed sleep phase. Some people, often teenagers and young adults, naturally fall asleep very late and struggle to wake. Melatonin, timed carefully, can help shift their schedule earlier.
- Shift work. It may help some night workers sleep during the day, though results are mixed. See shift workers, sleep and energy.
- Some children with autism or ADHD who have trouble sleeping, under a doctor's care.
For general insomnia in adults, the benefit is small. On average, melatonin helps people fall asleep a few minutes faster and sleep slightly longer. That is real but modest.
Less is often more
Many products contain 5 or 10 mg, but research suggests lower doses, often 0.5 to 3 mg, can work as well for many people. Higher doses can leave you groggy the next morning and are more likely to cause headaches or vivid dreams. If you try melatonin, start low.
Timing matters as much as the dose. For falling asleep, take it about 30 to 60 minutes before bed. For shifting your body clock, such as with jet lag or delayed sleep phase, a small dose taken a few hours before your target bedtime may work better. A sleep specialist can help you time it.
Labels are not always accurate
This is a real problem. A study published in JAMA in 2023 tested melatonin gummies sold in the United States and found that most did not match their labels. The actual amount ranged from about 74 percent to 347 percent of what the label claimed. Some products also contained CBD that was not listed. Because supplements are not approved by the FDA before sale, these problems can go undetected. See how supplements are regulated.
To improve your odds, choose a product with a USP Verified or NSF seal.
Keep it away from children
Because melatonin gummies look and taste like candy, accidental ingestions have soared. A CDC report found that calls to poison centers about melatonin in children rose by about 530 percent between 2012 and 2021. Most children had no symptoms or mild ones, but some needed hospital care. Store melatonin up high, in a locked cabinet if possible, and never call it candy.
Do not give melatonin to a child without talking to their pediatrician first. Sleep problems in children often improve with a consistent bedtime routine, less screen time and more daylight. See do kids need supplements.
Side effects and who should be careful
Melatonin is generally considered safe for short-term use in healthy adults. Side effects can include headache, dizziness, nausea and morning drowsiness. Do not drive or operate machinery if you feel drowsy.
Talk to your doctor before taking it if you:
- Are pregnant or breastfeeding
- Take blood thinners, blood pressure medicines, diabetes medicines, seizure medicines or drugs that suppress the immune system
- Have an autoimmune condition, depression or a seizure disorder
- Are an older adult, since drowsiness can increase fall risk
Little is known about the effects of taking melatonin every night for years. See supplement and drug interactions.
What to try before, or alongside, melatonin
- Keep a regular sleep and wake time, even on weekends.
- Get bright daylight in the morning. This helps set your body clock.
- Dim the lights and screens an hour before bed.
- Watch caffeine after lunch. See coffee and supplements.
- Keep your bedroom cool, dark and quiet.
- Consider CBT-I, cognitive behavioral therapy for insomnia. It is the first-choice treatment for long-term insomnia and works better than any supplement. Many programs are available online.
You may also be curious about magnesium. Read magnesium for sleep for an honest look at the evidence.
When to see a doctor
See a doctor if you snore loudly, wake up gasping, feel very sleepy during the day, or have struggled with sleep for more than three months. Sleep apnea and other conditions are common and treatable, and melatonin will not fix them.
The bottom line
Melatonin is a body clock signal, not a knockout pill. It works best for jet lag and shifted sleep schedules, and modestly for insomnia. Start with a low dose, choose a third-party tested product, and keep it away from children. For more, see our melatonin ingredient page and the sleep and relaxation goal page.