Melatonin May Help Night Shift Workers Repair DNA Damage

Melatonin supplements may help the body repair DNA damage linked to night shift work, according to a small clinical trial published in Occupational & Environmental Medicine. Researchers conducted a randomized placebo-controlled study involving 40 night shift workers, with half taking a 3 mg melatonin pill daily for 4 weeks and the other half taking a placebo. Among workers who took melatonin, urinary 8-OHdG levels—a marker of oxidative DNA damage repair capacity—were 80% higher during daytime sleep compared with the placebo group, suggesting melatonin may boost DNA repair while participants sleep after night work.

Night shift work disrupts the body's natural melatonin production, which may weaken DNA repair capacity and potentially increase cancer risk. However, researchers stress that the study was small and short-term, measuring only a biomarker rather than actual cancer outcomes. Most participants worked in healthcare, limiting generalizability. The International Agency for Research on Cancer has classified night shift work as probably carcinogenic to humans. Researchers emphasize that larger studies involving different doses and longer follow-up periods are needed before melatonin can be recommended as a long-term strategy for reducing cancer risk in night shift workers.