THE CURE INDEX
Helio Cure's evidence score based on human clinical trials for red light therapy.
A soft tissue injury is a tear, strain, or bruise in the muscles, tendons, or ligaments, usually caused by a sudden force or by overuse.
Red light therapy was found to be effective for soft tissue injury in a review of 5 human studies covering 322 participants. The CURE Index gives this condition 54 out of 100, indicating moderate confidence.
The reported benefits were less pain and better muscle function that were directly associated with red light therapy.
The 5 studies were 3 randomized controlled trials, 1 clinical trial, and 1 observational study. 4 reported effective outcomes, and 1 found no significant benefit.
450 nm and 640 nm were the most cited wavelengths, within a range of 450 to 1400 nm. Sessions lasted 3 to 30 minutes, 4 to 8 times per week, over 4 to 182 days.
EVIDENCE AT A GLANCE
The numbers behind the verdict.
MOST CITED WAVELENGTHS
The wavelengths appearing most often in studies that showed benefit for soft tissue injury.
450 nm · 640 nmTREATMENT PROTOCOL RANGES
The lowest and highest values used across soft tissue injury studies.
| PARAMETER | RANGE |
|---|---|
| Wavelength | 450-1400 nm |
| Session Duration | 3-30 minutes |
| Session Frequency | 4-8 per week |
| Therapy Duration | 4-182 days |
Note: We have excluded meta-analyses and reviews from scoring, but the list of human studies below contains them for your reference.
6 Human Studies on Red Light Therapy for Soft Tissue Injury
Study Reported Light Plus Manual Therapy Effective for Elbow Recovery
According to a 2025 observational study, 5 javelin throwers aged 15 to 24 were treated for injuries on the inner side of the elbow. Each athlete received a package of treatments that included low-level laser therapy (LLLT) alongside hands-on soft tissue work, dry needling, joint manipulation, and a strength and technique retraining program. All 5 returned to better-than-injury performance between 12 and 26 weeks after first being seen, and all were still free of symptoms at 6 and 12 months. The study concluded that the combined approach produced positive outcomes in these 5 athletes. Every athlete received all of the treatments together, so the contribution of light on its own cannot be separated.
- Study Type
- Observational Study
- Participants
- 5
- Treated Area
- Elbow
- Wavelength(s)
- 620-1400 nm
- Session Duration
- 3-4 minutes
- Therapy Duration
- 84-182 days
- Study Scope
- Medial Epicondylitis (Golfer's Elbow)
Study Title: A Multimodal Chiropractic Approach to the Treatment and Management of Medial Elbow Injuries in Elite Javelin Throwers: A Case Series.
Light Patch Outperformed Placebo for Muscle Power After Thigh Bruise
Striking the front of the thigh with a tennis ball fired from a serving machine to create a controlled bruise, a 2024 randomized controlled trial tested a light patch on muscle recovery. 46 healthy participants attended over 5 consecutive days and received either an active patch delivering blue light at 450 nm and red light at 640 nm or a placebo patch, worn for 30 minutes after the impact, with muscle force measured by machine at 2 speeds before and after. Peak force and average power at the faster test speed exceeded starting levels by 8.9% and 16.8% by day 4 in the active group. The trial found greater gains in peak force and average power with the active patch than with the placebo. Participants were healthy volunteers given a controlled bruise rather than patients with an existing injury.
- Study Type
- Randomized Controlled Trial
- Participants
- 46
- Treated Area
- Thigh
- Wavelength(s)
- 450, 640 nm
- Distance
- Contact
- Session Duration
- 30 minutes
- Session Frequency
- 4 per week
- Therapy Duration
- 4 days
- Study Scope
- Thigh Contusion
Study Title: Pulsed Red and Blue Photobiomodulation for the Treatment of Thigh Contusions and Soft Tissue Injury: A Randomized Controlled Trial.
Whiplash Patients Returned to Work Sooner After High Power Laser
Comparing high power laser therapy (HPLT) against standard physiotherapy, a 2013 randomized controlled trial examined neck injury from whiplash (a neck injury in which muscles, tendons and joint capsules are over-stretched). 135 patients with mild to moderate whiplash were assigned to 6 weeks of treatment, with 84 receiving HPLT using several wavelengths at once and 51 receiving physiotherapy, and no painkillers or anti-inflammatory drugs were allowed during that period. Pain scores fell to 20 in the laser group against 34.8 in the physiotherapy group, and the difference was statistically significant. Patients given the laser returned to work after 48 days against 66 days for the physiotherapy group, so HPLT appeared to shorten recovery.
- Study Type
- Randomized Controlled Trial
- Participants
- 135
- Treated Area
- Neck
- Wavelength(s)
- 780 nm
- Session Duration
- 5 minutes
- Therapy Duration
- 35, 42 days
- Study Scope
- Whiplash
Study Title: High power laser therapy treatment compared to simple segmental physical rehabilitation in whiplash injuries (1° and 2° grade of the Quebec Task Force classification) involving muscles and ligaments.
Soft Tissue Inflammation Improved More in Laser-Treated Patients Than Controls
114 patients with inflamed tendons, inflamed joint cushions, or inflammation where tendons attach to bone took part in a 1991 clinical trial of laser therapy. 97 patients received a helium-neon laser giving red light at 632.8 nm, infrared laser light, or both, applied either to single points or by scanning, while the remaining 17 formed a comparison group, with pain, movement, swelling, and muscle condition rated before treatment, at 2 weeks, and at 1 month. 86.8% of recent cases and 69.4% of long-standing ones were rated as improved, and shoulder cases did worst at 62%. The difference between the laser-treated patients and the comparison group was statistically significant, and laser therapy appeared to help most in recent cases.
- Study Type
- Clinical Trial
- Participants
- 114
- Treated Area
- Musculoskeletal Soft Tissues
- Wavelength(s)
- 632.8, 780-1400 nm
Study Title: [Laser therapy of inflammatory lesions of the soft parts of the locomotor system].
Review Found Weak Evidence for Light in Soft Tissue Injury
Across 9 possible ways to prevent or reduce the soft tissue damage radiation causes, a 2022 review assessed which might help people with head and neck cancer. Photobiomodulation (PBM) was 1 of the 9, alongside 8 drug- and oxygen-based treatments, and the review gathered existing work rather than collecting new patient data. None of the 9 treatments, PBM included, was backed by strong evidence for preventing the injury. The review found no basis for recommending any of them for immediate clinical use, though it described them as worth further study.
- Study Type
- Review
- Treated Area
- Mouth
- Wavelength(s)
- 600-1000, 633-685, 780-830 nm
- Session Frequency
- 2-7 per week
Study Title: Noninvasive Systemic Modalities for Prevention of Head and Neck Radiation-Associated Soft Tissue Injury: A Narrative Review.
No Added Benefit From Laser in Painful Soft Tissue Conditions
A double-blind design kept both patients and therapists unaware of which machine was active in a 1995 randomized controlled trial of low-level laser therapy (LLLT). 22 patients with a range of painful soft tissue conditions, including inflammation of the sole of the foot, an inflamed cushion at the hip, tennis elbow, knee pain and neck pain, were assigned to either a working device or an identical inactive one that looked and sounded the same, with the active device giving red light at 632.8 nm and near-infrared light at 780 to 830 nm at 35 mW and 1 J/cm² over 28 days. Improvement rates were 50% in the active group and 46% in the placebo group, with similar rates of worsening and of no change in each. The study concluded that LLLT has no significant effect and acts mainly as a placebo.
- Study Type
- Randomized Controlled Trial
- Participants
- 22
- Treated Area
- Musculoskeletal
- Wavelength(s)
- 632.8, 780-830 nm
- Session Frequency
- 8 per week
- Therapy Duration
- 28 days
Study Title: Low level laser therapy: a prospective double blind trial of its use in an orthopaedic population.
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: Sep 11, 2026