The hormone that helps people sleep may also help to reduce joint pain, finds a new study

That little pill beside your bed that you take to help you sleep may be doing more than just knocking you out. A new review of 23 clinical trials involving more than 2,000 people found that melatonin, a hormone your brain releases at night, can also help with long-term muscle and joint pain. The problem? It is mild relief and it barely works for pain after surgery.

The Sleep Hormone Moonlighting as a Painkiller

That's also why people take it when they're jet lagged or have insomnia. Melatonin is produced by the pineal gland in the brain after dark. But scientists now think it does more than just make you sleepy. Scientists believe that melatonin reduces pain signals transmitted through the brain and spinal cord, calms hyperactive nerves, reduces inflammation, and guards cells against oxidative stress, the damage that occurs when harmful molecules accumulate in the body.

Thus, the same hormone that puts your brain to sleep at night may also be turning down the volume on the pain you feel in your body. Thus, the same hormone that puts your brain to sleep at night may also be turning down the volume on the pain you feel in your body.

The Numbers Behind the Buzz

Across the pooled trials, people with chronic muscle and joint pain reported both less pain and better sleep after taking melatonin. On average, pain scores dropped by about nine points on a 100-point scale — roughly in the same ballpark as some anti-inflammatory drugs used in similar studies, though nobody has tested the two head-to-head.

Nine points out of a hundred is not a miracle cure. It's a nudge, not a knockout punch.

But don't jump to conclusions too soon

If you were hoping melatonin might replace your painkillers after an operation, the review has bad news. It made no meaningful difference to pain or sleep in surgical patients. One analysis found only a tiny 2.5-point dip on that same 100-point scale, far too small to matter to anyone recovering from a procedure.

The Sleep Connection Nobody Has Cracked Yet

Most people in the chronic pain trials already had poor sleep before starting melatonin. That raises an obvious question: does melatonin help more if you're already a bad sleeper, or does it work the same for everyone? None of the 23 trials split their results this way, so for now, it's anyone's guess.

There's also no clear answer on dosage. Trials used anywhere between 1mg and 10mg, and researchers couldn't pin down which amount works best. Some data hints that taking it for longer stretches helps more, but that's based on only a handful of studies. Higher doses look safe in other research, but barely anyone has tested whether they actually work better for pain.

Easy to Buy, But Not Risk-Free

In the United States, melatonin sits on supermarket shelves as a dietary supplement, no prescription needed. Cross the Atlantic, though, and it's a different story: in the UK, melatonin is prescription-only and officially approved just for short-term sleep problems and jet lag.

It's generally considered safe for short stretches, but side effects do show up, daytime grogginess, dizziness, headaches and nausea among them. Anyone with liver or kidney issues, or autoimmune conditions such as rheumatoid arthritis, is advised to check with a doctor or pharmacist before popping one.

Melatonin isn't about to replace physiotherapy, exercise or anti-inflammatory medicines for chronic muscle and joint pain, but it could earn a seat at the table alongside them, especially for people whose pain is tangled up with poor sleep. Bigger, better-designed trials are still needed before doctors can confidently say who stands to benefit most.

For now, that bottle on your nightstand remains, first and foremost, a sleep aid — with a promising, if modest, side hustle.