Melatonin Shows Comparable Efficacy to Opioids and NSAIDs for Chronic Musculoskeletal Pain, Large Meta-Analysis Finds
Key Insights
A meta-analysis of 23 randomized controlled trials involving 2,028 adults found melatonin reduced chronic musculoskeletal pain (search) by approximately 9 points on a 0–100 scale, comparable to opioids (search), NSAIDs (search), and paracetamol.
The study highlights melatonin's dual-action mechanism, simultaneously improving sleep quality and reducing pain, breaking the bidirectional cycle of pain-induced sleep disruption and sleep-deprivation-induced hyperalgesia.
Melatonin demonstrated an excellent safety profile with side effects (nausea, dizziness, headaches) occurring at rates similar to placebo and no evidence of dependence or respiratory depression.
A widely available, low-cost sleep supplement may offer a paradigm shift in chronic pain management, according to a new meta-analysis from the University of Sydney. Published in the journal PAIN, the study demonstrates that melatonin reduces chronic musculoskeletal pain (search) with therapeutic efficacy comparable to conventional analgesics including opioids (search), non-steroidal anti-inflammatory drugs (NSAIDs (search)), and paracetamol.
The findings carry significant weight given that musculoskeletal pain affects up to 47 percent of the global population, representing an enormous unmet need for safe, accessible, and non-addictive treatment options.
Magnitude of Pain Relief
The research team, led by PhD student Kangchao Wu from the Musculoskeletal Research Hub at the Charles Perkins Centre, analyzed data from 2,028 adults across 23 randomized controlled trials conducted in the United States, Russia, Brazil, Egypt, China, and other countries. Participants included individuals with low back pain (search), osteoarthritis (search), fibromyalgia (search), and those recovering from surgeries such as joint replacements and spinal procedures.
On a standard 0–100 pain rating scale, melatonin reduced subjective pain scores by an average of approximately nine points. The most methodologically rigorous trials demonstrated reductions closer to 10 points — a statistical magnitude that directly mirrors the relief provided by widely used prescription and over-the-counter pain medications.
"The level of pain relief we observed is comparable to some conventional treatments, but this does not mean melatonin should replace them," Wu said. "Rather, it may offer a safer additional option within a broader pain management plan."
The Dual-Action Mechanism
A key insight from the study is melatonin's ability to address the bidirectional relationship between chronic pain and sleep disruption. Pain destroys sleep quality, and sleep deprivation in turn heightens pain sensitivity — a phenomenon known as hyperalgesia. Melatonin appears to break this cycle by simultaneously targeting the neurological underpinnings of insomnia and mitigating peripheral musculoskeletal distress.
"For many patients, pain doesn't exist in isolation and is closely tied to poor sleep," Wu noted. "Melatonin appears to target both, which makes it particularly useful for people managing chronic pain."
The study also documented improvements in sleep quality across the analyzed trials, reinforcing the well-established clinical link between pain and sleep.
Dosing and Administration
Across the trials, dosing protocols varied by condition and clinical setting. For chronic musculoskeletal conditions, daily bedtime doses ranged from 3 mg to 10 mg, with 3 mg serving as the most commonly used baseline. For postoperative recovery, bedtime doses scaled between 1 mg and 10 mg, with 5 mg to 6 mg being the most frequent. Melatonin was generally administered at bedtime or up to one hour before sleep.
Notably, the researchers found no clear dose-response relationship, indicating that higher doses do not automatically confer superior pain relief. This finding precludes a single "best" dose recommendation based on current evidence.
Safety Profile and Regulatory Context
Unlike opioids (search), melatonin carries zero risk of chemical dependence or respiratory depression. Across the three-month testing windows examined in the included trials, the most commonly reported side effects were nausea, dizziness, and headaches, occurring at rates virtually identical to placebo. No serious adverse events were reported, and melatonin is generally considered safe for short-term use of less than three months.
"Melatonin is already in people's homes, it's inexpensive, and we know it's safe," Wu said. "What's exciting is that melatonin may also help manage chronic pain, opening the door to reducing reliance on medications that come with more risks."
In Australia, melatonin is not available as a standard over-the-counter supplement. Most products require a prescription, although low-dose melatonin (2 mg or less) can be supplied by a pharmacist without a prescription for short-term treatment of insomnia in adults aged 55 years and older. The supplement is typically low cost — often less than $1.50 per tablet in Australia.
Drug Repurposing and Clinical Integration
The study underscores the growing potential of drug repurposing — applying existing, well-characterized treatments to new indications to deliver faster and more accessible health benefits.
"We're taking a medication we already understand and applying it to a problem that affects a huge proportion of the global population," said co-author Professor Paulo Ferreira, Director of the Musculoskeletal Research Hub.
The researchers emphasize that melatonin is not intended to replace every pain medication. Instead, after consultation with a physician, it may serve as a protective adjunct — particularly for patients whose physical pain is actively compounded by sleep disorders.
"Our advice isn't for melatonin to replace every pain medication," Wu said. "Instead, after consultation with a doctor, it may be used as an adjunct to existing treatments, particularly for people who also experience sleep problems."
While the authors acknowledge that further large-scale studies will strengthen the evidence base, they stress that the current findings are sufficiently robust to support cautious clinical uptake. As concerns continue to mount around long-term opioid use and the risks associated with other analgesic classes, melatonin represents a safer alternative that could be integrated into care relatively quickly.