THE CURE INDEX
Helio Cure's evidence score based on human clinical trials for red light therapy.
Sleep quality refers to how well a person sleeps, including how easy it is to fall asleep, stay asleep, and wake feeling rested.
The CURE Index scored sleep quality 95 out of 100, indicating strong confidence, based on a review of 4 human studies covering 300 participants that found red light therapy to be effective.
Red light therapy was associated with improvements in sleep quality across all studies reviewed.
The 4 studies included 2 randomized controlled trials and 2 observational studies. All 4 studies reported effective outcomes.
The most cited wavelength was 850 nm, with a range of 633 to 850 nm across included studies. Sessions lasted 30 to 180 minutes, delivered 3 to 12 times per week, over therapy durations of 1 to 42 days.
EVIDENCE AT A GLANCE
The numbers behind the verdict.
MOST CITED WAVELENGTH
The wavelength appearing most often in studies that showed benefit for sleep quality.
850 nmTREATMENT PROTOCOL RANGES
The lowest and highest values used across sleep quality studies.
| PARAMETER | RANGE |
|---|---|
| Wavelength | 633-850 nm |
| Session Duration | 30-180 minutes |
| Session Frequency | 3-12 per week |
| Therapy Duration | 1-42 days |
4 Human Studies on Red Light Therapy for Sleep Quality
Sleep and Fatigue Improved With Light Therapy in Nursing Homes
Cold limbs fell from 50% to 6.7% among nursing home residents who received low-level light therapy (LLLT) in a 2025 observational study. 120 older adults received LLLT at 660 nm and 850 nm through an LED cap applied to head acupoints for 30 minutes, 3 times per week over 42 days. The study also reported improvements in sleep quality, fatigue, and depression among participants who received LLLT.
- Study Type
- Observational Study
- Participants
- 120
- Treated Area
- Head
- Wavelength(s)
- 660, 850 nm
- Session Duration
- 30 minutes
- Session Frequency
- 3 per week
- Therapy Duration
- 42 days
Study Title: Low-level light therapy for sleep quality, fatigue, depression, and cold limbs in older adults in nursing homes: A feasibility trial.
Night-Shift Nurses Reported Better Sleep After 830 nm Laser
Researchers in Taiwan studied whether photobiomodulation (PBM) could improve sleep quality and quality of life in night-shift nurses in a 2025 observational study. 60 nurses received an 830 nm laser array applied to the palm and a localized painful area at a fluence of 252 J/cm2, with therapy periods of 30 and 90 days. Sleep quality and quality of life scores improved in nurses who received PBM, the study reported.
- Study Type
- Observational Study
- Participants
- 60
- Treated Area
- Hand And Local Painful Site
- Wavelength(s)
- 830 nm
- Therapy Duration
- 30, 90 days
Study Title: Effects of photobiomodulation on the sleep quality and quality of life of night-shift nurses.
Low-Level LED Light Therapy Improved Sleep in Shift-Work Nurses
A 2025 randomized controlled trial evaluated low-level LED light therapy for sleep problems and psychological symptoms in shift-work nurses with insomnia. 64 nurses were assigned to an experimental group and a control group of 32 each, with the experimental group receiving 660 nm and 850 nm light through a cap to acupressure points on the scalp for 30 minutes, 3 times per week over 28 days. Researchers found that the experimental group scored significantly lower on insomnia, depression, anxiety, and stress measures than the control group, suggesting that LED light therapy may improve sleep quality and psychological wellbeing in shift-work nurses.
- Study Type
- Randomized Controlled Trial
- Participants
- 64
- Treated Area
- Head
- Wavelength(s)
- 660, 850 nm
- Session Duration
- 30 minutes
- Session Frequency
- 12 per week
- Therapy Duration
- 28 days
Study Title: The Effectiveness of Low-Level LED Light Therapy for Sleep Problems, Psychological Symptoms, and Heart Rate Variability in Shift-Work Nurses: A Randomized Controlled Trial.
Photobiomodulation Outperformed Placebo for Mild Sleep Complaints
56 adults with mild sleep complaints took part in a 2022 double-blind, randomized, placebo-controlled trial testing photobiomodulation (PBM) for sleep quality. All participants (22 males and 34 females, aged 25 to 64) were divided into 4 dose groups receiving 0, 1, 4, or 6.5 J/cm2 of 850 nm and 633 nm PBM applied to the face, neck, and hands at 5 mW/cm2 for 180 minutes, 5 times per week over 28 days. The study reported better sleep quality outcomes in those who received active PBM doses compared to the placebo group.
- Study Type
- Randomized Controlled Trial
- Participants
- 56
- Treated Area
- Upper Body
- Wavelength(s)
- 633, 850 nm
- Distance
- 7.87 inches
- Session Duration
- 180 minutes
- Session Frequency
- 5 per week
- Therapy Duration
- 28 days
Study Title: Effects of Near-Infrared Light on Well-Being and Health in Human Subjects with Mild Sleep-Related Complaints: A Double-Blind, Randomized, Placebo-Controlled Study.
The CURE Index (Clinical Understanding of Red-light Evidence) by Helio Cure is a 0-100 evidence score based on published human clinical trials. Higher scores mean stronger evidence. Read full methodology →
Data is powered by AI and reviewed by the Helio Cure team.
This page is for educational purposes only. Not medical advice. Consult a healthcare provider before starting red light therapy. Helio Cure does not diagnose, treat, or cure any medical condition.
Last updated: Jul 05, 2026