Can Red Light Therapy Improve Sleep Quality? What Two Trials Found

Good sleep is one of the more common reasons people ask whether red light therapy is worth trying — separate from its use for pain or skin. Because red light doesn't suppress melatonin the way blue light does, researchers have tested whether exposure to it before bed can actually help people sleep better.

What the research looked at

A 2012 randomized trial split twenty elite Chinese female basketball players into a red-light group and a placebo group. The treatment group received 30 minutes of whole-body red light (around 658–670 nm) every night for 14 days, while researchers tracked sleep quality and blood melatonin levels.

More recently, a 2025 randomized controlled trial tested low-level LED light therapy in shift-work nurses — a population with chronic, clinically diagnosed insomnia from disrupted schedules, not just poor sleep habits.

What they found

In the basketball players, the red-light group's Pittsburgh Sleep Quality Index scores improved significantly more than the placebo group's, and their melatonin levels nearly doubled — from about 22 pg/mL at baseline to almost 39 pg/mL — while the placebo group barely changed.

The nurses' trial found an even larger effect: after four weeks, the treatment group's insomnia severity scores dropped from an average of 12.6 to 4.3, and the share of participants with clinically significant insomnia fell from 94% to 16%. The control group saw no meaningful change.

What this means in practice

Both trials point the same direction, but neither is the final word — the basketball study was small (10 per group) and specific to young elite athletes, and while the nurses' trial was larger and in a more clinically relevant population, it's one study. If you're using red light therapy to help with sleep, the protocol that's actually been tested is a nightly session in the run-up to bed, used consistently over weeks — not an occasional session.