A review of studies related to melatonin side effects and weight gain shows that the supplements won't cause you to pack on the pounds. In fact, preliminary research suggests it may help with weight loss.
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What Is Melatonin?
The pineal gland in the brain makes melatonin, a hormone that plays a key role in the sleep cycle, says the American Academy of Family Physicians (AAFP). It lets the body know when it's time to go to sleep and when it's time to awaken. Natural levels of the hormone are highest at night. Levels rise when it's dark and decline when it's light, notes the Mayo Clinic.
Melatonin supplements come in two forms — natural and synthetic. The natural form is produced by animals, while the synthetic form is made in a laboratory. Opt for the synthetic variety, because the natural supplement may be contaminated with a virus. The Food and Drug Administration doesn't guarantee the purity, safety or efficacy of melatonin, says the AAFP.
Many people take melatonin for sleep disorders. Research shows it has value for alleviating problems in falling or staying asleep, says the Mayo Clinic. It also improves sleep duration and quality in people who have jet lag or who have jobs that require shift work.
The supplement is sold in doses ranging from 1 to 10 milligrams or higher, but recommended doses range from 0.5 to 3 milligrams, according to the Cleveland Clinic. Research shows that lower doses produce sleep more effectively.
Take melatonin 60 to 90 minutes before bedtime. Never take more than the recommended amount of the supplement. Instead of storing it in a bathroom, which is likely warm and humid, store it in a cool, dry place.
Melatonin Pills and Weight Gain
No link exists between melatonin supplements and weight gain, but it's possible the pills may help with weight loss. An animal study published in Pineal Research in February 2018 shows that, in rodents, melatonin reduces obesity without changing food intake, which indicates it may have a fat-burning effect. Animal investigations also indicate a link between melatonin and increased brown fat, an effect associated with a weight advantage.
While the experiment involved animals rather than humans, it's important because of a key finding. Results indicated that melatonin did, indeed, promote fat burning and increase brown fat, factors that may contribute to its benefit for weight control.
A small clinical trial featured in Diabetes in May 2019 examined melatonin's brown-fat activating effect on participants with a melatonin deficiency. It involved only 18 people, but it's worth noting because, to the authors' knowledge, it's the first nonanimal study on the topic.
The results of the trial showed that taking melatonin increased the volume of brown fat. Because low levels of melatonin are usually associated with aging, future research is warranted, the authors concluded.
Noteworthy findings of a small study of 56 menopausal women published in Przeglad Menopauzalny in December 2014 shed additional light on the link between melatonin and weight control. In the menopausal women, who tend to have reduced levels of melatonin, the supplements improved quality of sleep and reduced body weight. The authors noted that melatonin is safe to use on a long-term basis for treating obesity in this segment of the population.
Melatonin Side Effects
Melatonin supplements are safe for short-term use, notes the Mayo Clinic. While many sleep medications are habit-forming and produce a hangover effect, melatonin is unlikely to cause these effects. However, it does have side effects, the most common of which are dizziness, drowsiness, headaches and nausea.
In addition, melatonin has less-common side effects, including confusion, disorientation and impaired alertness, as well as irritability, low blood pressure and abdominal cramps. The supplement also may cause mild anxiety and tremors, along with short-term depression. Due to possible daytime drowsiness, don't drive or use machinery within five hours of taking melatonin.
Higher doses increase the likelihood of some of the side effects like daytime drowsiness and impaired concentration. They can also reduce body temperature and lead to feelings of being chilled, notes the Cleveland Clinic.
Melatonin can interact with an array of medications such as contraceptives, immune system suppressants and drugs for seizures, blood clotting and diabetes. Check with your doctor before taking melatonin.
Best Natural Sleep Aids
As with melatonin, the FDA doesn't regulate other natural sleep aids, warns the National Sleep Foundation. While people often assume that products labeled "natural" are safe, this doesn't always hold true. Aside from the possibility of side effects and drug interactions, the long-term effects are often unknown.
Perhaps the best sleep aid option is exercise because it has side benefits rather than side effects. A few studies indicate exercise significantly improves sleep in people with chronic insomnia.
Research examining the effects of long-term exercise on sleep found the practice enhanced sleep quality and slightly lengthened sleep duration, reports the foundation. The thing to remember is not to work out within two hours of your bedtime.
A study published in the March/April 2018 American Journal of Therapeutics explored the benefit of Montmorency tart cherry juice for insomnia. It included only 11 participants, but because it's a placebo-controlled crossover clinical trial, the findings bear consideration.
Results of the study showed the juice increased sleep duration and quality. No adverse effects were observed, so the authors concluded that tart cherry juice offers a safe, effective way to alleviate insomnia.
Another possible insomnia aid may come from a warm cup of chamomile tea before bed. A small clinical trial featured in the Journal of Advanced Nursing in February 2016 tested the effects of chamomile tea for insomnia in 80 women. The findings revealed that the tea improved sleep quality.
Read more: 12 Foods That Help You Fall (and Stay) Asleep
Your sleeping environment can affect the quality of your rest, too, says Johns Hopkins Medicine. Keep your bedroom cool: The ideal temperature is between 65 and 72 degrees.
Also, make sure your bedroom is dark, because bright light inhibits the body's release of melatonin, says the National Sleep Foundation. Rather than turning on a lamp, use a flashlight when you get up at night to go to the restroom. Blue light from a smartphone and other electronics can interfere with sleep, so keep them in another room.
- American Academy of Family Physicians: "Melatonin"
- Mayo Clinic: "Melatonin"
- Pineal Research: "Melatonin Increases Brown Adipose Tissue Mass and Function in Zücker Diabetic Fatty Rats: Implications for Obesity Control"
- Diabetes: "Melatonin Increases Brown Adipose Tissue Volume and Activity in Patients With Melatonin Deficiency"
- Przeglad Menopauzalny: "The Effect of Melatonin Supplementation on the Quality of Sleep and Weight Status in Postmenopausal Women"
- Mayo Clinic: "Is Melatonin a Helpful Sleep Aid — and What Should I Know About Melatonin Side Effects?"
- Cleveland Clinic: "Melatonin: How Much Should I Take for a Good Night’s Rest?"
- National Sleep Foundation: "Debunking Sleep Myths: Are Natural Sleep Aids Safe?"
- National Sleep Foundation: "How Does Exercise Help Those With Chronic Insomnia?"
- Johns Hopkins Medicine: "Natural Sleep Aids: Home Remedies to Help You Sleep"
- American Journal of Therapeutics: "Pilot Study of the Tart Cherry Juice for the Treatment of Insomnia and Investigation of Mechanisms"
- Journal of Advanced Nursing: "Effects of an Intervention With Drinking Chamomile Tea on Sleep Quality and Depression in Sleep Disturbed Postnatal Women"
- National Sleep Foundation: "Melatonin and Sleep"