Regardless of whether it truly helps with sleep or not, Dr. Ramkissoon doesn't recommend taking melatonin long-term.
The scientific evidence of the long-term use of melatonin is limited, says Dr. Weiss. The current clinical consensus is that daily melatonin consumption is considered safe.
Short-term use of melatonin may not be harmful but there is insufficient evidence on its long-term safety, according to the National Center for Complementary and Integrative Health. And in some cases, relying on melatonin could simply mask another problem.
What is a safe melatonin dose? According to Michael Grandner, director of the Sleep and Health Research Program at the University of Arizona, “melatonin is very safe if taken in normal doses,” which is anything between 0.5 mg and 5 mg.
Melatonin lasts for about four hours before it's 95 percent absorbed by your body, meaning you'll want to take your melatonin supplement 30 minutes to two hours before you plan to sleep for the best results.
Melatonin should only be taken for a maximum of 13 weeks to treat short-term sleep problems in adults, but longer courses may be used on the advice of a specialist.
Furthermore melatonin has been shown to have valuable effects on cardiovascular health, blood pressure, and endothelial function and it might benefit patients with heart failure.
You cannot build up a tolerance to melatonin. This means that the same dosage of melatonin taken every day will not build up in the body, and you won't need a higher dosage over time to experience the same effect.
The possible dangers of using melatonin long-term
As with many hormones in our bodies, having too much or too little melatonin in your system long term can cause health concerns. The problem when taking a melatonin supplement is that since it's not a drug, there's no oversight or regulation by the FDA.
“If melatonin for sleep isn't helping after a week or two, stop using it,” says Buenaver. “And if your sleep problems continue, talk with your health care provider. If melatonin does seem to help, it's safe for most people to take nightly for one to two months. “After that, stop and see how your sleep is,” he suggests.
Unlike with many sleep medications, with melatonin you are unlikely to become dependent on it, have less response to it after repeated use or experience a hangover effect.
Natural alternatives to melatonin, such as magnesium, valerian root, l-theanine, chamomile, and passionflower, are all-natural remedies that have been used for centuries to promote relaxation and help people get a better night's sleep.
Melatonin's target sites are both central and peripheral. Binding sites have been found in many areas of the brain, including the pars tuberalis and hypothalamus, but also in the cells of the immune system, gonads, kidney, and the cardiovascular system (39, 40).
In several clinical trials, melatonin was found to be well tolerated and not associated with serum enzyme elevations or evidence of liver injury. Despite wide scale use, melatonin has not been convincingly linked to instances of clinically apparent liver injury.
If you've been drinking alcohol, it's also not safe to take melatonin. Melatonin is also not for you if you're pregnant or breastfeeding. Researchers simply don't have enough data to know if it's safe for fetuses or breastfed babies.
Generally safe
Your body likely produces enough melatonin for its general needs. However, evidence suggests that melatonin supplements promote sleep and are safe for short-term use. Melatonin can be used to treat delayed sleep phase and circadian rhythm sleep disorders in the blind and provide some insomnia relief.
Over-the-counter melatonin may come in standard amounts like 1 milligram, 3 milligrams, or 5 milligrams. It is important to note that cutting or splitting tablets for a smaller starting dose can result in inconsistent dosing.
Sleep deprivation can make this logic seem sound, but experts say taking melatonin in the middle of the night can actually make your sleep schedule even worse.
Melatonin levels decline gradually over the life-span and may be related to lowered sleep efficacy, very often associated with advancing age, as well as to deterioration of many circadian rhythms.