THE CURE INDEX
Helio Cure's evidence score based on human clinical trials for red light therapy.
A scar is the permanent mark left on the skin after a wound or a burn has healed.
5 human studies with 95 participants have tested this therapy on scars. Red light therapy for scars scores 62 out of 100 on the CURE Index, which reads as moderate confidence in the verdict.
Red light therapy may flatten and soften scars and bring their color closer to the skin around them.
The set holds 2 randomized controlled trials, 1 clinical trial, and 2 observational studies, of which 4 were rated Effective, and 1 was rated Partially Effective.
Wavelengths sat in a narrow band, from 595 nm to 808 nm, and 632 nm was the most cited. Sessions were short, from 4 seconds to 25 minutes, given 2 to 30 times a week, over courses that ran from 2 days to 84 days.
EVIDENCE AT A GLANCE
The numbers behind the verdict.
MOST CITED WAVELENGTH
The wavelength appearing most often in studies that showed benefit for scars.
632 nmTREATMENT PROTOCOL RANGES
The lowest and highest values used across scars studies.
| PARAMETER | RANGE |
|---|---|
| Wavelength | 595-808 nm |
| Distance | 0.39-27.6 inches |
| Session Duration | 4 seconds-25 minutes |
| Session Frequency | 2-30 per week |
| Therapy Duration | 2-84 days |
5 Human Studies on Red Light Therapy for Scars
Helium-Neon Laser Improved Raised Burn Scars in Children
Comparing a laser-treated half of each scar against an untreated half, a 2018 randomized controlled trial in Egypt tested helium-neon laser treatment for raised burn scars in children. 15 children aged 2 to 10 had each scar divided in 2, with 1 half receiving 632.8 nm light at 119 mW/cm² and 16 J/cm² in 25-minute sessions twice a week for 84 days, on top of a cream applied to both halves, and the other half receiving the cream alone. According to the trial, the laser-treated half scored better than the cream-only half on a standard scar rating scale and on an ultrasound measure of thickness, while blood flow through the scar did not differ between the halves. No adverse effects were reported.
- Study Type
- Randomized Controlled Trial
- Participants
- 15
- Treated Area
- Arm
- Wavelength(s)
- 632.8 nm
- Distance
- 27.56 inches
- Session Duration
- 25 minutes
- Session Frequency
- 2 per week
- Therapy Duration
- 84 days
Study Title: Evaluation of scars in children after treatment with low-level laser.
Study Found Combined Laser Therapy Best for Children's Facial Scars
Among 41 children aged 1.5 to 5 with facial scars after injury, a 2015 observational study compared 2 laser approaches against no treatment. 14 children received low-level laser therapy (LLLT) alone at 670 nm and 3 to 5 J/cm², 17 received LLLT combined with a high-level pulsed dye laser at 595 nm and 9 to 11 J/cm², and 10 were left untreated, with scars rated by both the child's parent and an observer at 4, 8, and 12 weeks. Both treated groups appeared to improve on every rated feature, while the untreated group showed no improvement. The combined approach appeared to give the larger gain on every feature except color and flexibility.
- Study Type
- Observational Study
- Participants
- 41
- Treated Area
- Face
- Wavelength(s)
- 595, 670 nm
- Session Duration
- 10 minutes
- Session Frequency
- 7 per week
- Therapy Duration
- 14-21 days
- Study Scope
- facial Scar
Study Title: Comparison of quality of facial scars after single low-level laser therapy and combined low-level with high-level (PDL 595 nm) laser therapy.
Scars Treated With LED Light Outperformed Untreated Scars After Surgery
3 patients aged 27 to 57 took part in a 2010 observational study testing near-infrared (NIR) LED treatment to prevent raised scars and keloids from forming. After scars on both sides of the body were revised by surgery or by carbon dioxide laser, each patient treated 1 of the pair at home every day for 30 days with 805 nm light at 30 mW/cm², leaving the other as a control, with results judged on a standard scar rating scale, on photographs, and with a device that measures surface texture. The study found that the treated scar did better than the untreated one on every measure, with assessments running up to a year afterward. Safety was tracked throughout, and no treatment-related side effects of note were reported.
- Study Type
- Observational Study
- Participants
- 3
- Treated Area
- Skin
- Wavelength(s)
- 805 nm
- Distance
- 0.984 inches
- Session Duration
- 15 minutes
- Session Frequency
- 30 per week
- Therapy Duration
- 30 days
- Study Scope
- Hypertrophic Scar
Study Title: Prophylactic low-level light therapy for the treatment of hypertrophic scars and keloids: a case series.
17 of 19 Burn Scars Improved After 670 nm Laser
A 2004 clinical trial tested low-level laser therapy (LLLT) on burn scars, treating part of each scar and leaving the rest untreated for comparison. 19 patients with 19 burn scars were treated twice a week for 56 days with a 400 mW 670 nm laser at 4 J/cm², with the beam sized to match each scar and the distance set by the clinician. Scores on a standard scar rating scale fell from 7.10 to 4.68 in the treated areas, against 6.10 to 5.88 in the untreated areas, and 17 of the 19 scars appeared to improve. Longer-standing scars appeared to respond better than newer ones. No negative effects were reported.
- Study Type
- Clinical Trial
- Participants
- 19
- Treated Area
- Skin
- Wavelength(s)
- 670 nm
- Distance
- Clinician-controlled
- Session Frequency
- 2 per week
- Therapy Duration
- 56 days
- Study Scope
- Brun Scar
Study Title: Low Level Laser Therapy--a conservative approach to the burn scar?
No Difference Between Laser and Placebo Groups for Scar Tissue
No statistically significant difference between the treated group and the placebo group appeared in any measure, in a 2013 randomized controlled trial of low-level laser therapy (LLLT) for scar tissue. 17 volunteers in Portugal were grouped by how old their scars were and then randomly assigned to 2 groups. 9 received 808 nm light at 1000 mW/cm² and 4 J/cm² in 4-second sessions, 3 times a week for 35 days, and 8 received the same routine with the device switched off. On its own, the treated group showed a statistically significant improvement in scar appearance, and older scars tended to be less thick. The authors concluded that LLLT appears to have a positive effect on scar appearance and on the thickness of older scars, but that its influence on scar tissue cannot be stated with confidence.
- Study Type
- Randomized Controlled Trial
- Participants
- 17
- Treated Area
- Skin
- Wavelength(s)
- 808 nm
- Distance
- 0.39 inches
- Session Duration
- 4 seconds
- Session Frequency
- 3 per week
- Therapy Duration
- 35 days
Study Title: Efficacy of low-level laser therapy on scar tissue.
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: Oct 18, 2026