Most adults should start with 1 mg of melatonin and increase only if needed. That’s lower than the 5 mg or 10 mg tablets lining store shelves, but sleep experts consistently recommend starting at the bottom. Higher doses aren’t more effective and can actually backfire, making you drowsy during the day while disrupting the very sleep cycle you’re trying to fix.
The Right Starting Dose
Cleveland Clinic sleep specialists recommend beginning at 1 mg, then increasing by 1 mg each week until you’re falling asleep faster, with a ceiling of 10 mg. Most people find their sweet spot well below that ceiling. The Mayo Clinic puts the typical recommended maximum at 5 mg or fewer, noting that doses above this level carry more side effects without added benefit.
Your body naturally produces melatonin in tiny amounts from the pineal gland, with levels peaking during darkness and dropping in daylight. Even a 1 mg supplement delivers far more melatonin than your brain produces on its own. This is why low doses often work just as well as high ones: you’re not trying to sedate yourself, you’re sending your brain a “it’s nighttime” signal.
When to Take It
Take melatonin about 90 minutes before you want to fall asleep. This lines up with your body’s natural melatonin rise and gives the supplement time to reach effective levels in your bloodstream. Taking it too early or too late can shift your internal clock in the wrong direction, which is especially important for people using melatonin to adjust to a new schedule.
Doses for Jet Lag
Jet lag requires a slightly different approach. The CDC notes that just 0.5 to 1 mg is often enough to shift your circadian rhythm, and doses above 5 mg are specifically not recommended because excess melatonin lingers in your system and can end up active at the wrong time of day.
Timing matters more than dose size here. For eastward travel, take melatonin about 90 minutes before your target bedtime in the new time zone to push your clock earlier. For westward travel, taking it when your internal clock thinks it’s morning can help delay your rhythm. The key pitfall: taking melatonin when your body is already producing it at peak levels (roughly midnight to 5 a.m. on your internal clock) doesn’t accomplish much.
For jet lag, the NHS suggests up to 6 mg if a lower dose isn’t sufficient, taken for a short period after arrival.
Doses for Older Adults
Natural melatonin production holds steady from your late teens until around age 40, then gradually declines for the rest of your life. This is one reason sleep quality often worsens with age and why older adults are drawn to melatonin supplements.
Clinical trials in adults aged 55 to 80 have tested slow-release melatonin at 2 mg nightly. At that dose, it modestly reduced the time it took to fall asleep, with side effects comparable to a placebo. The American Academy of Sleep Medicine, however, gave only a weak recommendation against this formulation for chronic insomnia, citing limited evidence of benefit. For older adults, the lowest effective dose is the safest approach, particularly because melatonin can interact with blood pressure and blood sugar regulation, both common concerns in this age group.
Why Your Supplement May Not Match the Label
One complication with choosing a dose: the amount of melatonin in your supplement may not be what the label says. A study published by researchers who tested 31 melatonin products found that more than 71% were off by more than 10% from their labeled dose. The actual melatonin content ranged from 83% less than claimed to 478% more. Even different batches of the same product varied by as much as 465%.
Perhaps more concerning, 26% of the supplements tested contained serotonin, a neurotransmitter that is far more tightly regulated. Because melatonin is sold as a dietary supplement rather than a drug in the United States, it doesn’t face the same manufacturing standards as prescription medications. Choosing products with a third-party testing seal (USP, NSF, or ConsumerLab) gives you better odds of getting what’s on the label.
Common Side Effects
Melatonin is generally well tolerated. The most frequently reported side effects are daytime drowsiness, headache, dizziness, nausea, and stomach discomfort. Some people experience dry mouth, itchy skin, strange dreams, or night sweats. Serious side effects are rare, occurring in fewer than 1 in 1,000 people.
If you accidentally take an extra tablet or two beyond your usual dose, it’s unlikely to cause harm. That said, consistently taking high doses raises the risk of more significant effects, including changes in heart rate or blood pressure and reduced glucose tolerance.
Drug Interactions Worth Knowing
Melatonin can interact with several common medication categories. It may worsen blood pressure control in people already on blood pressure medication. Combined with sedatives or other sleep aids, it can amplify drowsiness beyond what’s safe. It may also reduce the effectiveness of anti-seizure medications. People taking blood thinners or antidepressants should be aware of potential interactions as well.
If you take any of these medications, the interaction risk is another reason to keep your melatonin dose as low as possible and to mention supplement use at your next appointment.
Practical Approach to Finding Your Dose
Start at 1 mg, taken 90 minutes before your desired bedtime. Give it a full week before increasing. If 1 mg doesn’t help, move to 2 mg the next week, and continue adding 1 mg weekly up to a maximum of 5 mg for general sleep support. Most people respond somewhere in the 1 to 3 mg range.
Melatonin works best as a short-term tool or for specific situations like jet lag and schedule adjustments. It signals your brain that it’s time to sleep, but it won’t override poor sleep habits. A dark room, consistent bedtime, and limited screen exposure in the evening all amplify what melatonin does naturally, often making a lower dose more effective than a higher one taken in a bright room while scrolling your phone.