Melatonin Supplementation for Night Shift Workers: Oxidative DNA Damage Repair, Explained

Melatonin, DNA Repair, and the Night Shift: What a New Study Reveals

The hospital hums at 03:17. Lights too bright for this hour, monitors whispering numbers you don’t want to see. You can feel the algorithm even here—charting, pinging, selling the promise of “peak performance” in the dead of night.

But the body keeps its own books. And lately, the ledger has a new line: melatonin supplementation for night-shift workers—and what it might mean for oxidative DNA damage repair.

The Research Behind the Headline

A randomized, placebo-controlled trial from Canada explored a simple, biologically grounded question:

If night work suppresses melatonin—and if melatonin helps repair oxidative DNA damage—could a timed dose before daytime sleep restore balance?

Forty night-shift workers were randomized to 3 mg melatonin or placebo for four weeks, taken with food one hour before daytime sleep. Researchers tracked urinary 8-hydroxy-2′-deoxyguanosine (8-OH-dG)—a biochemical marker of oxidative DNA repair.

Key result: during daytime sleep, the melatonin group showed a ~1.8× increase in urinary 8-OH-dG compared with placebo (95% CI 1.0–3.2; p = 0.06). No difference was seen during the subsequent night shift.

In short, the repair signal appeared where the dose landed—during recovery sleep after the shift.

Source: Zanif U., Lai A.S., Parks J., et al. (2025). Melatonin supplementation and oxidative DNA damage repair capacity among night shift workers: a randomized placebo-controlled trial. Occupational and Environmental Medicine, 82(1), 1–6. https://doi.org/10.1136/oemed-2024-109824

Plain-Language Takeaways

Dose & Timing: 3 mg melatonin with food ≈ 1 hour before daytime sleep, for 4 weeks. Primary Readout: Higher urinary 8-OH-dG = more oxidative lesion repair completed. Effect Size: ~80% higher repair signal during day sleep on melatonin vs placebo. Limitations: Small sample; light exposure uncontrolled; short duration; variable absorption; no long-term outcome data.

What This Might Mean for You

If you’re a clinician on rotating nights, the value of a book is the stillness it gives you between alarms; the value of melatonin might be quieter still—a nudge to the repair crews sweeping oxidative debris after the shift.

Not a miracle. Not a hall pass. A nudge.

Practical Considerations (Educational, Not Medical Advice)

• Discuss with your clinician before starting any supplement.

• If appropriate, consider the study timing: with food, ~1 hour before day-sleep.

• Protect your light environment on the way home (dark glasses, dim kitchen, low bathroom light).

• Pair with circadian hygiene: consolidated sleep window, cool/dark room, caffeine cut-off, regular anchor times.

Melatonin and light are dance partners; step on one and the other stumbles.

Transparency & Purpose

This article is part of The Shift Worker’s Paradox project—bridging clinical science and lived experience to help healthcare workers make sense of night-shift physiology. For references, author background, or contact: www.shiftworkersparadox.com

The Human Note

We work in fluorescent midnights. Our bodies still prefer stars. If a 3 mg dose gives the DNA repair crew a better flashlight while you sleep, that’s worth knowing. The rest is craft: quiet rooms, good rituals, and the old-fashioned work of recovery.

Author: R.E. Hengsterman, MSN, MA, M.E., RN

Registered nurse, night-shift administrator, and author of The Shift Worker’s Paradox

Nursewhowrites.com

For educational purposes only. Not medical advice.