Does this supplement live up to its hype?

By Alistair Gardiner
Published April 21, 2021

Key Takeaways

If you’ve been wandering the vitamin and supplement aisle of your local grocery store recently, you may have noticed an “out of stock” sign where the melatonin used to be. That’s because this supplement has become one of America’s most popular sleep aids, and demand spiked last year. According to an article published in Business Insider, US consumers spent more than $825 million on melatonin supplements in 2020—a whopping 42.6% increase in sales compared with 2019.

Recently, this dietary supplement has been promoted not just as a sleep aid, but as a way to prevent or treat certain chronic diseases—and some are even taking it to relieve pandemic-induced stress. But history tells us that what manufacturers claim their supplements can do doesn’t always match up with what they have been proven to do. And, because there is less FDA oversight for dietary supplements compared with OTC or prescription medications, companies could falsely advertise the quantity of melatonin in their product, according to the Business Insider article.

“Because melatonin is not [as] regulated, there’s no guarantee about the purity of what you're buying,” said Jennifer Martin, of the American Academy of Sleep Medicine Board of Directors. “There’s no guarantee that each pill in a bottle has the same amount of melatonin in it.”

So does melatonin live up to the hype? Some studies do suggest that melatonin plays other important roles in the body beyond sleep, and it’s even being studied for its effects on COVID-19. However, more research is needed to fully understand these effects. 

Here’s what the most recent research tells us about using melatonin to improve your health.

What is melatonin?

Melatonin is a hormone secreted primarily by the pineal gland in the brain, and it helps to regulate our sleep-wake cycle (or circadian rhythm), according to the National Center for Complementary and Integrative Health (NCCIH). As a dietary supplement, melatonin can be made naturally from the pineal gland of animals, however, it is usually produced synthetically. 

Melatonin supplements are typically used as a sleep aid to provide relief for insomnia or disrupted sleep rhythms caused by jet lag or working night shifts. According to Brent Bauer, MD, of the Mayo Clinic, the supplement is “generally safe for short-term use,” with a very low likelihood of developing dependence, becoming habituated, or experiencing hangover effects, as can occur with many sleep medications.

Meanwhile, if you suffer from insomnia, here’s a look at seven steps that can improve sleep hygiene and help you conquer your sleep problems, or at least diminish their hold on you.

Does melatonin have therapeutic properties?

Recent research indicates that melatonin may help with more than just sleep. Studies in a review published in Antioxidants in 2020 have demonstrated that the hormone boasts lipophilic antioxidant properties, anti-inflammatory effects, immunomodulatory actions, and protective abilities against free radicals.

The review’s authors note that oxidative stress is a common characteristic of various metabolic, degenerative, and cardiovascular disorders, and cancer. Melatonin plays a protective role both intracellularly and extracellularly, with its abundant mitochondria, which prevent free-radical damage. 

“Melatonin has been proven to be twice as active as vitamin E, believed to be the most effective lipophilic antioxidant,” the authors wrote.

According to the review, studies have shown that reduced melatonin levels are a risk factor for various cardiovascular diseases, including ischemic myocardial injury, hypertension, atherosclerosis, and heart failure. Likewise, evidence indicates that melatonin supplementation can help reduce nocturnal hypertension, blood pressure, platelet aggregation, and circulating catecholamines. One study cited by the authors found that melatonin alleviated right ventricular hypertrophy and dysfunction, and reduced interstitial fibrosis and oxidative stress in a rat model. Strong evidence for the efficacy of melatonin as a treatment for cardiovascular diseases in humans, however, is still lacking.

Studies cited in the review have also demonstrated that melatonin may be effective against various bacterial and viral infections, due to its immunoregulatory functions and protective mechanisms against free radicals. For example, lab trials have demonstrated that melatonin can help in fighting off Staphylococcus aureus, carbapenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, and sepsis, particularly septic shock.

Melatonin can also help relieve the systemic inflammation that viruses cause. “Melatonin’s beneficial effects have been postulated against flu infections, and also against SARS-CoV-2 virus responsible for the pandemic that has hit the world in recent months,” the authors wrote, adding, “melatonin reduces inflammation and oxidative stress related to aging, cardiovascular diseases, diabetes, all conditions associated with an increased risk of mortality in patients with COVID-19 disease.” However, more research is needed to better understand the interaction between exogenous melatonin and viruses, they added. 

As for melatonin’s role in fighting COVID-19, the NCCIH notes, “Current research looking at the effects of melatonin on COVID-19 is only in the early stages. There are a few randomized controlled trials (studies evaluating melatonin in people) in progress. At this point, it is too soon to reach conclusions on whether melatonin is helpful for COVID-19.”

Beyond this, the authors note, melatonin may have neuroprotective effects via its “free radical scavenging activity,” and can even help moderate obesity, according to some studies. While further study into melatonin’s efficacy against various disorders (not related to sleep) is required, the authors concluded that melatonin supplementation in combination with traditional therapies could increase the efficiency of the treatment for infectious disorders, cardiovascular disease, cancer, and neurodegenerative disorders.

According to a review published in the International Journal of Molecular Medicine in March 2021, melatonin’s anti‑inflammatory and antioxidative functions mean that it likely serves as a protective agent against bone-related diseases, like fractures, osteoporosis, and osteoarthritis. The authors of the review point out that melatonin has been shown to increase new bone regeneration, neovascularization, and the number of osteoblast-like cells, as well as cartilage and callus, at the site of fractures.

Is melatonin safe?

Short-term use of melatonin supplementation is generally considered safe for most people, however, data on long-term use is lacking, according to the NCCIH. Based on practice guidelines from the Academy of Sleep Medicine and the American College of Physicians, “There’s not enough strong evidence on the effectiveness or safety of melatonin supplementation for chronic insomnia to recommend its use,” noted the NCCIH. 

Some health experts have expressed concern over the regulation of melatonin products. According to one article published in the Journal of Clinical Sleep Medicine, the levels of melatonin found in supplement products can vary drastically from what’s advertised.

There is also concern over melatonin’s association with type 2 diabetes, with one study concluding that increased melatonin signaling is a risk factor for the disease.

That said, evidence suggests it’s not unsafe to use melatonin for temporary or minor sleep disorders, according to the Mayo Clinic’s Dr. Bauer. Of note, the most common side effects of melatonin are headaches, dizziness, and nausea. Melatonin isn’t recommended for those with dementia or elderly individuals, because it can cause daytime drowsiness. 

Meanwhile, you can learn more here about ways to improve your sleep, including what to eat, and what not to eat before you go to bed.  

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