Can Taking Melatonin Help with Weight Loss?

Key Takeaways: 

• Melatonin is a hormone that regulates your sleep-wake cycle.

• Some research shows melatonin supplements might promote modest weight loss, as well as fat loss and muscle gain.

• More research is needed on melatonin’s role in weight loss and whether it may be a useful obesity treatment.
  

Melatonin is a hormone your body makes to help control your sleep-wake cycle. It's also a common supplement that people use to manage jet lag and sleep disorders. Some research suggests melatonin might promote weight loss, too.

Read on to learn more about using melatonin for weight loss, including how it may work and whether it should be part of your weight loss plan.

There is little evidence that melatonin has a substantial effect on weight loss, but it may help enhance the quality of your sleep and encourage healthy rest and recovery during your weight loss journey. 

A 2021 systematic review looked at 23 studies on melatonin and obesity. Researchers found that taking melatonin supplements reduced body weight by about 1 pound.

According to the study, higher doses were more effective, but not by much. In doses of 8 milligrams (mg) or more, melatonin reduced body weight by about 1.7 pounds. But in these studies, melatonin didn’t significantly affect body mass index (BMI) or waist circumference. 

Melatonin may be more effective for specific populations. For example, one older study of postmenopausal women with obesity found that 5 mg of melatonin, combined with a balanced diet, led to a minor reduction in BMI after 16 weeks. 

But newer research has not come to the same conclusions about melatonin supplements and weight loss.

A 2015 study looked at women who’ve reached menopause taking melatonin or a placebo each night for a year.

Compared to the placebo group, in the melatonin group: 

• Body fat mass decreased by 6.9 percent 

• Lean mass (like muscle) increased by 5.2 percent 

• Adiponectin, a hormone that plays a role in energy metabolism and insulin sensitivity, increased by 21 percent 

This study found that doses of at least 3 mg of melatonin could improve body composition in women after menopause, with greater improvements in those with overweight or obesity. However, the researchers noted that BMI did not differ significantly between the groups. 

While there is no definitive relationship between melatonin supplements and weight loss, there are other ways melatonin may indirectly promote healthy weight loss.

For example, melatonin is known to improve sleep quality, which may keep your appetite in check.

While more research is needed, melatonin may contribute to weight loss by: 

• Promoting fat burning

• Regulating appetite 

• Increasing how many calories your body burns

• Improving gut microbiota (the healthy bacteria in your gut)

• Preventing inflammation 

• Reducing oxidative stress

• Regulating your circadian rhythm

• Helping you get enough sleep

Low levels of melatonin can lead to insulin resistance, glucose intolerance, and sleep disturbances, which could lead to health problems, weight gain, and obesity. If you have low levels of melatonin, taking supplements could theoretically prevent these issues.

Melatonin supplements may help promote healthy sleep, which is an important component of any healthy weight loss plan.  

Melatonin supplements may be a helpful sleep aid if you do shift work, have jet lag, or have a sleep-wake cycle that’s very delayed (delayed sleep-wake phase disorder). But more research is needed on the weight loss front.

If you regularly have trouble sleeping, consider talking with a healthcare provider about how sleep might be impacting your weight loss plan. They can let you know whether melatonin is safe for you to take, and if it may be helpful as weight loss treatment.

Risks of Melatonin 

Short-term melatonin use is generally considered safe, and side effects are usually mild. 

Side effects of melatonin include:

• Morning drowsiness 

• Nausea

• Dizziness 

• Headaches

There isn’t much research on long-term melatonin use, but some studies suggest that large doses may cause adverse effects in people with diabetes. For example, according to one 2022 study, men with type 2 diabetes taking 10 mg of melatonin every night for 3 months became less responsive to insulin, meaning that blood sugar management tended to get worse.

And there isn’t any research on melatonin in women who are pregnant or breastfeeding. Consult with your healthcare provider if you’re considering melatonin.

You should also check with your provider before taking melatonin if you’re on blood-thinning medications or have epilepsy. Your provider may want to monitor your health while you take the supplement. 

Finally, melatonin is a dietary supplement, so the Food and Drug Administration (FDA) doesn’t regulate it like it does prescription medications. Melatonin products may contain higher amounts of melatonin than indicated on the label, as well as other, unlisted ingredients. If you’re considering it, make sure to buy melatonin from a reputable brand. 

Diet and exercise modifications, prescription weight loss medications, and some other supplements are proven to be much more effective at helping you lose weight and improve your overall health.

Lifestyle interventions for weight loss include: 

• Including more nutritious foods

• Eating a balanced diet

• Practicing portion control during meals

• Doing more physical activity, such as exercise, in an effort to burn more calories than you take in from your diet

• Getting enough sleep 

• Lowering your mental and physical stress

Some supplements are known to be effective for weight loss. That’s because they’re already part of a healthy, balanced diet. These include protein and fiber.

Weight loss medications are also available for people with obesity or overweight with a weight-related health condition, like high blood pressure (hypertension), type 2 diabetes, or high cholesterol.

Weight loss medications include: 

• Semaglutide (Ozempic^®, Wegovy^®)

• Tirzepatide (Mounjaro^®, Zepbound^®)

• Liraglutide (Victoza^®, Saxenda^®)

• Metformin 

• Topiramate 

→ Learn more: Are Weight Loss Medications Effective?  

More research is needed to determine whether melatonin may have weight loss effects. So far, no definitive links have been found. While some studies show modest weight loss in participants – about 1 to 2 pounds – no decrease in BMI was observed.

Melatonin acts on many processes in your body, such as regulating your sleep and circadian rhythm. This may indirectly promote weight loss.

If you’re looking for weight loss treatments with more scientific backing, take our free online weight loss assessment to learn more about your options.

Does melatonin help you lose weight? 

A direct causative relationship between taking melatonin supplements and weight loss has not been found. According to older research, taking supplements may contribute to modest weight loss.

For example, one review found it could promote modest weight loss of about 1 to 2 pounds.

Melatonin may work in indirect ways to promote weight loss by increasing energy use and regulating your circadian rhythm and sleep.

How much melatonin should I take to lose weight? 

More research is needed to find the best dose of melatonin for weight loss. Older research suggests doses of up to 8 mg a day may be effective and safe for weight loss. Check with your healthcare provider to find the safest dose for you.

How long does it take to lose weight on melatonin? 

There is no definitive evidence that taking melatonin supplements will lead to any significant long-lasting weight loss. However, research from 2014 saw a reduction in BMI after 16 weeks of melatonin supplementation in women after menopause.

What’s the best time to take melatonin for weight loss? 

More research is needed to know the best time to try melatonin for weight loss. Taking supplements about 2 to 3 hours before bedtime are known to promote sleep and circadian rhythm regulation.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards.