Scientists tested whether a nightly melatonin pill could help people who work at night fix tiny DNA errors that build up in the body.
Why Night Shifts Are Hard on the Body
Melatonin is a hormone that tells us when it is dark and time to sleep. When we work through the night, the body makes less melatonin. Less melatonin can make it harder for the body to repair oxidative DNA damage – a normal kind of wear and tear.
If DNA damage is not fixed well, it may raise the risk of certain cancers over many years.
How the Study Was Done
Forty adults who regularly worked at least two night shifts a week for six months took part. They were split into two groups:
- One group took a 3 mg melatonin pill each day for four weeks.
- The other group took a placebo pill that looked the same.
Both groups took the pill with food about an hour before they tried to sleep during the day.
What the Researchers Measured
Participants gave urine samples before the trial started and again near the end. The urine was tested for a chemical called 8‑OHdG, which shows how much oxidative DNA repair is happening.
People also wore activity trackers so the researchers could see how long they slept.
What They Found
During daytime sleep, the melatonin group had about 80 % higher levels of 8‑OHdG than the placebo group. This suggests that melatonin may have increased DNA repair while they slept.
During the next night‑shift, there was no noticeable difference between the two groups.
Why These Results Matter
The study hints that melatonin could give the body a extra signal to fix DNA when night‑shift workers nap during the day. However, the trial was small, short, and only looked at a lab marker—not actual cancer rates.
Most participants worked in health care, so the findings might not apply to all night‑shift jobs. The study also could not control how much daylight the participants were exposed to, which can affect natural melatonin levels.
What Experts Say Next
Scientists say bigger, longer studies are needed. Future research should test different melatonin doses and follow people for many years to see if the supplement really lowers cancer risk.
Until then, melatonin should be seen as a possible aid for sleep and DNA repair, not a proven cancer‑prevention tool.