Sleep Aid or Pain Reliever? New Research Finds Melatonin May Do Both

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Millions of people reach for melatonin to fall asleep faster or fight jet lag. Now, researchers say the same cheap, widely available supplement might also help with something else entirely: chronic pain.

A new systematic review published in the journal PAIN pooled data from 23 randomized clinical trials involving more than 2,000 adults. The international research team, led by scientists at the University of Sydney, wanted to know whether melatonin could meaningfully reduce pain in people with long-term musculoskeletal conditions such as osteoarthritis, low back pain, and fibromyalgia.

Their answer: yes, modestly — but only for chronic pain, not for pain after surgery.

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What the Researchers Found

The study combined results from trials conducted in countries including the United States, Brazil, Russia, Egypt, and China. Participants either had chronic pain lasting at least three months, or were recovering from musculoskeletal surgery such as joint replacements or spinal procedures.

Across the highest-quality chronic pain studies, melatonin reduced pain scores by roughly 9 to 10 points on a 100-point scale, compared with placebo or other treatments. For context, a widely cited 2020 Cochrane review found that ibuprofen — a standard over-the-counter painkiller — reduces pain by about 7.7 points on the same scale.

That does not mean melatonin works exactly like ibuprofen, or that the two were tested head-to-head. But the size of the effect was similar enough that researchers say it deserves attention.

“Melatonin is already in people's homes, it's inexpensive, and we know it's safe,” said lead author Kangchao Wu, a doctoral researcher at the University of Sydney's Musculoskeletal Research Hub, in comments released by the university.

Melatonin also improved sleep quality among participants with chronic pain — a finding the researchers say reinforces just how closely pain and sleep are connected.

The picture looked different for people recovering from surgery. In that group, melatonin did not produce a meaningful reduction in pain, and researchers say the supplement may simply need more time to take effect than a typical post-operative recovery allows.

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Why Sleep and Pain Are So Closely Linked

Doctors have long known that poor sleep and pain feed off each other. Pain makes it harder to fall and stay asleep, and poor sleep, in turn, makes pain feel worse. It's a cycle that millions of people with chronic conditions know all too well.

The scale of the overlap is striking. Up to 95 percent of people with fibromyalgia and around 70 percent of people with osteoarthritis report ongoing sleep problems. Other research has shown that people who struggle to sleep are more likely to develop chronic pain years down the line.

Part of the explanation lies in the body's stress response. Pain raises cortisol levels and keeps the brain alert, cutting into the deep sleep the body needs to recover. Poor sleep then increases inflammation and weakens the brain's natural ability to dampen pain signals — making the original pain feel even more intense.

Melatonin may interrupt this cycle in several ways. Beyond regulating the sleep-wake cycle, it has antioxidant and anti-inflammatory properties, and some researchers believe it may calm an overactive nervous system — one of the mechanisms thought to drive chronic pain conditions.

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A Slow-Acting Supplement, Not a Quick Fix

One of the clearest findings in the review is that melatonin does not act like a typical painkiller. Most of the trials used daily doses of around 2 to 3 milligrams over periods of weeks, not days — and the benefits appeared to build gradually rather than kick in immediately.

That gradual action likely explains why melatonin fell short after surgery. Post-operative pain stems from acute tissue injury and usually needs fast, strong pain relief — something melatonin, with its slower, more regulatory effects, isn't well suited to provide in the short trial periods studied so far.

The researchers also found no evidence that higher doses worked better. Larger amounts of melatonin did not translate into stronger pain relief, suggesting more is not necessarily better when it comes to this particular supplement.

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What This Means If You're Considering It

Despite the encouraging numbers, the researchers are careful to frame their findings as preliminary rather than a green light for widespread use. The certainty of the evidence was rated low to moderate, and the pain reduction observed falls below the threshold many doctors consider clinically significant on its own.

Side effects reported across the trials were generally mild, including nausea, dizziness, headache, and drowsiness. Still, melatonin can interact with certain medications, and experts recommend caution for specific groups.

People who are pregnant or breastfeeding, elderly individuals at risk of falls, those with epilepsy, or anyone taking other medications should speak with a doctor before trying melatonin for pain, according to the study authors. Most trials also only tracked use for under three months, meaning long-term safety has not yet been well studied.

Wu suggested melatonin could serve as an add-on treatment for people with chronic musculoskeletal pain who also struggle with sleep — but stressed that it should complement, not replace, standard medical care and treatments such as physical therapy.

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Looking Ahead

The findings add melatonin to a growing list of existing, well-understood drugs being explored for new uses — an approach known as drug repurposing that can bring potential treatments to patients faster and more cheaply than developing something entirely new.

But the authors are clear that larger, longer, and more rigorous trials are still needed before melatonin could be formally recommended for chronic pain. For now, it remains a promising lead rather than a proven treatment — one more piece of evidence in the long-known link between how well we sleep and how much pain we feel.

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Sources

1. University of Sydney — "Study finds melatonin may ease chronic pain" (July 1, 2026): https://www.sydney.edu.au/news-opinion/news/2026/07/01/study-finds-melatonin-may-ease-chronic-pain.html
2. PMC (National Institutes of Health / National Library of Medicine) — Wu K. et al., "Efficacy and effectiveness of melatonin for the management of musculoskeletal pain: a systematic review and meta-analysis," PAIN (2026): https://pmc.ncbi.nlm.nih.gov/articles/PMC13528901/
3. New Atlas — "Melatonin helps relieve chronic pain and improve sleep": https://newatlas.com/chronic-pain/chronic-pain-melatonin/

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