Summary: A new study suggests that a common, low-cost sleep supplement could radically shift the treatment landscape for pain. The study demonstrates that melatonin significantly reduces chronic musculoskeletal pain with a therapeutic efficacy matching conventional pharmaceuticals.
By evaluating data from over 2,000 adults across 23 randomized controlled trials, researchers proved that melatonin targets the bidirectional relationship between physical agony and sleep fragmentation, offering a highly accessible, non-addictive adjunct for integrated pain management plans.
Key Facts
- The Repurposing Efficiency: Rather than spending decades developing expensive new molecules, this study highlights the power of drug repurposing—taking melatonin, an affordable compound whose safety profile is already thoroughly mapped, and applying it to global pain management.
- The 10-Point Pain Reduction: On a standard 0–100 pain rating scale, melatonin reduced subjective pain scores by an average of 9 points. The most methodologically rigorous trials demonstrated reductions closer to 10 points—a statistical magnitude that directly mirrors the relief provided by NSAIDs and prescription opioids.
- The Dual-Action Mechanism: Chronic pain and sleep disruption feed into a devastating biological loop; pain destroys sleep, and sleep deprivation heightens pain sensitivity (hyperalgesia). Melatonin breaks this cycle by simultaneously treating the neurological roots of insomnia and mitigating peripheral musculoskeletal distress.
- Dosing Protocols: For chronic musculoskeletal conditions, daily bedtime doses ranged from 3 g to 10 mg (with 3 mg operating as the baseline). For postoperative recovery, bedtime doses scaled between 1 g and 10 mgs (with 5 mg to 6 mg being the most common). No clear dose-response relationship was found, indicating that higher doses do not automatically guarantee superior relief.
- Safety & Regulatory Distinction: Unlike opioids, melatonin carries zero risk of chemical dependence or respiratory depression. Mild side effects across the three-month testing windows included brief episodes of nausea, dizziness, or headaches at rates virtually identical to standard placebos.
- Clinical Integration Guidance: Researchers emphasize that melatonin is not a magic eraser designed to instantly replace all existing pain protocols. Instead, it should be integrated into comprehensive care plans under direct medical supervision as a highly protective adjunct—especially for patients whose physical pain is actively compounded by sleep disorders.
Source: University of Sydney
A sleep supplement widely used to treat insomnia could help reduce reliance on some of the most common and potentially harmful pain medications, new research from the University of Sydney suggests.
Published in PAIN, the study found melatonin can reduce chronic musculoskeletal pain with effects in a similar range to medications such as opioids, non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol.
With musculoskeletal pain affecting up to 47 percent of people globally, the findings point to a low-cost, widely available option that could shift how chronic pain is managed.
Melatonin for chronic pain
“Melatonin is already in people’s homes, it’s inexpensive, and we know it’s safe,” said lead author and PhD student Kangchao Wu from the Musculoskeletal Research Hub at the Charles Perkins Centre and the School of Health Sciences.
“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.”
The research highlights the growing potential of drug repurposing – using existing treatments in new ways to deliver faster, 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 study analysed data from 2028 adults across 23 randomised controlled trials conducted in countries including the United States, Russia, Brazil, Egypt and China. Participants included people with conditions such as low back pain, osteoarthritis and fibromyalgia, as well as those recovering from surgeries including joint replacements and spinal procedures.
On average, the study found that melatonin reduced pain by around nine points on a 0-100 scale, with the most rigorous trials showing reductions closer to 10 points, a similar magnitude to widely used pain medications.
The supplement also improved sleep quality, reinforcing the well-established link between pain and sleep.
“For many patients, pain doesn’t exist in isolation and is closely tied to poor sleep,” Mr Wu said.
“Melatonin appears to target both, which makes it particularly useful for people managing chronic pain.”
Across the trials, the dose and timing of melatonin varied depending on the condition and setting. For chronic musculoskeletal pain, doses typically ranged from 3 to 10 mg, with 3 mg per day the most commonly used. For postoperative pain, doses ranged from 1 to 10 mg, with 5 to 6 mg most common. Melatonin was generally taken at bedtime or up to one hour before sleep.
The researchers did not find evidence of a clear dose-response relationship, meaning no single “best” dose can be recommended from the current evidence.
Melatonin safety, side effects and access in Australia
Melatonin is typically low cost – often less than $1.50 per tablet in Australia – and is generally well tolerated, with mild, short-term side effects and no evidence of dependence.
The most commonly reported side effects found in the study were nausea, dizziness and headaches. Overall rates were similar to placebo and no serious adverse events were reported. Melatonin is generally considered safe for short-term use of less than three months.
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.
Researchers emphasise that patients should discuss melatonin with their doctor before use, especially if they are taking other medicines or have underlying health conditions.
“Our advice isn’t for melatonin to replace every pain medication,” Mr 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.”
As concerns grow around long-term use of opioids and other pain treatments, the findings highlight a safer alternative that could be integrated into care relatively quicky.
While the researchers say further large-scale studies will strengthen the evidence base, they emphasise the current findings are strong enough to support cautious uptake.
“The level of pain relief we observed is comparable to some conventional treatments, but this does not mean melatonin should replace them,” Mr Wu said. “Rather, it may offer a safer additional option within a broader pain management plan.”
Key Questions Answered:
A: This connection boils down to a brutal, two-way highway in human biology: the loop between pain and sleep. When you suffer from chronic low back pain or osteoarthritis, your sleep architecture is heavily fractured. But what many don’t realize is that sleep deprivation fundamentally rewires your nervous system, turning up the volume dial on your brain’s pain receptors, a state known as hyperalgesia. Melatonin doesn’t just act as a gentle biological clock to put you to sleep; it possesses powerful anti-inflammatory and neuroprotective qualities. By repairing sleep quality and settling down brain inflammation, it dampens the nervous system’s hypersensitivity, calming physical pain from the top down.
A: No, that is definitely not what the researchers are advising. Lead author Kangchao Wu explicitly notes that melatonin should not be treated as a sudden, total replacement for conventional medicine. Instead, it should be viewed as a highly effective, non-toxic adjunct—a supplementary tool to blend into an existing care plan. For instance, if a patient uses melatonin to successfully manage their pain baseline and fix their sleep, they may find they can significantly lower their daily dose of riskier medications like opioids or NSAIDs, protecting their liver, stomach, and heart over time.
A: Across the 23 clinical trials, melatonin proved to be incredibly safe for short-term use under three months, with zero evidence of chemical dependence or withdrawal. A tiny fraction of patients experienced minor, passing side effects like mild nausea or a morning headache, but these occurred at the exact same rates seen in the placebo groups. However, availability varies wildly depending on your country. While it is sold over-the-counter for a few dollars in places like the United States, countries like Australia heavily regulate it. In Australia, it requires a doctor’s prescription, though pharmacists can supply low doses to adults aged 55 and older for short-term insomnia. Regardless of where you live, you should always consult your physician before adding it to a chronic medical regimen.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this pain research news
Author: Emily Fraser
Source: University of Sydney
Contact: Emily Fraser – University of Sydney
Image: The image is credited to Neuroscience News
Original Research: The findings will appear in PAIN
