Several supplements and over-the-counter options can help you fall asleep faster or stay asleep longer, with melatonin, magnesium, valerian root, and L-theanine being the most widely used. Each works differently, and the best choice depends on whether your problem is falling asleep, staying asleep, or both. Here’s what the evidence actually supports.
Melatonin: Best for Timing Problems
Melatonin is the hormone your brain naturally produces when it gets dark, signaling that it’s time to sleep. Taking it as a supplement works best when your internal clock is out of sync, whether from jet lag, shift work, or a sleep schedule that’s drifted later than you’d like. It’s less effective as a general-purpose sedative. If you’re lying in bed at your normal bedtime with a racing mind, melatonin probably isn’t your best option.
For short-term insomnia, the NHS recommends a 2mg slow-release tablet taken one to two hours before bedtime, used for no longer than 13 weeks. For longer-term sleep problems managed with a doctor, the dose can gradually increase up to 10mg. For jet lag, a 3mg standard tablet at bedtime (no earlier than 8pm, no later than 4am at your destination) for up to five days is the typical approach.
One issue worth knowing: melatonin supplements are often wildly inaccurate. Testing by Australia’s Therapeutic Goods Administration found that 12 out of 18 imported melatonin products had melatonin content significantly different from what the label claimed. Five of those deviated by more than 50%, and one product labeled as containing 10mg had no melatonin at all. If you use melatonin, look for brands that have been verified by third-party testing organizations.
Magnesium: A Calming Mineral
Magnesium plays a role in hundreds of processes in your body, including the regulation of your nervous system. When levels are low, your muscles stay tense, your stress response stays elevated, and falling asleep gets harder. Many adults don’t get enough magnesium through diet alone, which makes supplementation a reasonable starting point for sleep trouble.
The form matters. Magnesium glycinate and magnesium bisglycinate are the types most commonly recommended for sleep because they’re well absorbed and less likely to cause digestive issues than cheaper forms like magnesium oxide. Clinical trials have used doses around 200 to 500mg of elemental magnesium daily, typically taken in the evening. A pilot trial published in Medical Research Archives used 1 gram per day of a magnesium supplement and found improvements in both sleep quality and mood over a two-week period. Start on the lower end and increase gradually, since too much magnesium at once can cause loose stools.
Valerian Root: A Traditional Sedative
Valerian root has been used for centuries as a sleep aid, and modern research suggests it does more than just provide a placebo effect. It appears to work by boosting the activity of your brain’s main calming chemical, the same system targeted by prescription sedatives, though at a much milder level.
Animal studies have shown that valerian extract at higher doses significantly increased sleep duration and reduced the time it took to fall asleep. In one study, the 300mg/kg dose shortened the time to fall asleep more effectively than melatonin and extended total sleep time. The active compound, valerenic acid, seems to be the key ingredient, so look for extracts standardized to contain it.
In practice, most human studies use between 300 and 600mg of valerian root extract taken 30 minutes to two hours before bed. It’s not a knockout pill. Many people notice the effects build over one to two weeks of consistent use rather than working dramatically on the first night.
L-Theanine: For a Busy Mind
L-theanine is an amino acid found naturally in green tea. It doesn’t make you drowsy directly. Instead, it promotes relaxation without sedation, which makes it particularly useful if your main sleep problem is that your brain won’t quiet down at night. It increases calming brain activity and helps ease the mental chatter that keeps you staring at the ceiling.
A systematic review and meta-analysis published in Sleep Medicine Reviews confirmed that L-theanine consumption improved sleep outcomes, though the researchers noted that the ideal dose and duration still need further clarification. Most supplements provide 100 to 400mg per dose. It’s considered very safe, and some people combine it with magnesium for a stronger calming effect. Taking it 30 to 60 minutes before bed is the most common approach.
Tart Cherry Juice: A Food-Based Option
Tart cherry juice is one of the few foods with direct evidence for improving sleep. Tart cherries are a natural source of melatonin and also contain compounds that reduce inflammation, which may contribute to their sleep-promoting effects.
Most studies used two 8-ounce (240mL) glasses per day, one in the morning and one in the evening, one to two hours before bed. A 2018 study of adults over 50 found that those drinking tart cherry juice twice daily slept more than the placebo group over two weeks. A 2010 study of older adults with insomnia used a tart cherry-apple juice blend with a similar twice-daily schedule and also found benefits. It’s not as potent as a supplement, but if you prefer getting sleep support from food rather than pills, it’s a reasonable option. Go for tart (Montmorency) cherries specifically, not sweet cherry varieties.
Over-the-Counter Antihistamines: Use With Caution
Drugstore sleep aids like diphenhydramine (the active ingredient in many “PM” products) and doxylamine work by blocking histamine, a chemical that promotes wakefulness. They’ll make you drowsy, but they come with real downsides.
Your body builds tolerance quickly, so they stop working within days to weeks of regular use. Harvard sleep expert Dr. Lawrence Epstein notes they’re acceptable for the occasional bad night but aren’t meant for long-term use. In older adults, the risks increase substantially: these medications can cause confusion, impaired balance, and a higher risk of falls. They also tend to leave you groggy the next morning, which partially defeats the purpose of getting “better” sleep.
If you use them, treat them as a once-in-a-while backup rather than a nightly habit.
What Not to Mix
Alcohol is the most common thing people combine with sleep aids, and it’s also the most dangerous pairing. Mixing alcohol with any sedating substance, including over-the-counter antihistamines and even herbal products like melatonin or valerian, can amplify drowsiness, impair judgment, and in serious cases slow breathing to dangerous levels. This risk increases with age.
Prescription sleep medications combined with alcohol are especially risky. Barbiturate-type sedatives mixed with alcohol can be fatal due to breathing that slows dramatically or stops entirely. Even the newer “Z-drug” sleep medications carry risks of excessive drowsiness, impaired memory, and poor coordination when combined with a drink. The simple rule: if you’re taking anything to help you sleep, skip the alcohol that night entirely.
Choosing the Right Option
- Your schedule is off (jet lag, late nights, shift work): melatonin, timed correctly, is your best bet.
- You feel tense or restless at bedtime: magnesium glycinate addresses the physical tension that keeps you awake.
- Your mind races when you lie down: L-theanine helps quiet mental activity without making you feel drugged.
- You want something mild and natural: valerian root or tart cherry juice, used consistently, can improve sleep quality over time.
- You need to sleep tonight and nothing else is available: an over-the-counter antihistamine will work in a pinch, but don’t rely on it.
Combining options is common and generally safe. Magnesium with L-theanine is a popular pairing for anxious sleepers. Melatonin with magnesium works well for people whose schedule is off and who also feel physically wound up. Start with one thing at a time so you can tell what’s actually helping, and give any supplement at least a week or two before deciding it isn’t working.