Melatonin, the over-the-counter supplement best known for helping people fall asleep, may also ease chronic musculoskeletal pain about as effectively as common over-the-counter painkillers, according to a large new analysis from the University of Sydney.
The study, published in the journal PAIN, pooled results from 23 randomized controlled trials involving more than 2,000 adults across nine countries, including the United States, Brazil, China, Iran, and Turkey. Participants included people living with chronic low back pain, osteoarthritis, and fibromyalgia, as well as patients recovering from major surgeries such as knee and hip replacements.
For people with long-term musculoskeletal pain, melatonin reduced pain scores by roughly nine points on a 100-point scale — a reduction the study’s authors say falls within a similar range to what’s typically reported for medications including opioids, NSAIDs such as ibuprofen, and paracetamol (acetaminophen). The effect for short-term, post-surgical pain was far less clear, suggesting melatonin’s benefit may be specific to chronic rather than acute pain.
“Melatonin is already in people’s homes, it’s inexpensive, and we know it’s safe,” said Kangchao Wu, the study’s lead author and a PhD student at the University of Sydney’s Charles Perkins Centre. Musculoskeletal pain affects as much as 47 percent of people worldwide, the researchers note, making a low-cost, widely available option potentially significant on a public health scale.
Part of the appeal, researchers say, is that melatonin may be addressing two problems at once. Chronic pain and poor sleep frequently feed into each other — pain disrupts sleep, and poor sleep tends to worsen pain sensitivity — and melatonin’s established role as a sleep aid may help interrupt that cycle rather than simply masking pain the way traditional painkillers do.
The researchers were unable to identify a single “best” dose from the available evidence, since trials in the analysis used varying amounts without a clear pattern linking higher doses to better results. They also flagged an important caveat: separate observational research presented at the American Heart Association’s 2025 Scientific Sessions found that melatonin use beyond a year was associated with higher rates of heart failure diagnosis and hospitalization among people with insomnia, though that link has not been shown to be causal.
Health experts generally consider melatonin safe for short-term use at low doses, but say anyone considering it for chronic pain — rather than occasional sleeplessness — should talk with a doctor first, particularly given the unresolved questions around long-term safety.
