Does infrared light therapy improve wound healing?
Moderate EvidenceIT DEPENDS
Moderate evidence suggests infrared light therapy accelerates wound healing by enhancing cellular metabolism and collagen synthesis. Results are consistent in animal models but more variable in human trials, with effect sizes depending on wavelength and wound type.
The Verdict
Moderate evidence suggests infrared light therapy accelerates wound healing by enhancing cellular metabolism and collagen synthesis. Results are consistent in animal models but more variable in human trials, with effect sizes depending on wavelength and wound type.
What the Evidence Shows
Infrared light therapy, particularly near-infrared (NIR) wavelengths between 600-1000nm, is proposed to enhance wound healing through photobiomodulation. The mechanism involves absorption by cytochrome c oxidase in mitochondria, increasing ATP production, modulating reactive oxygen species, and stimulating growth factor release. Animal studies consistently demonstrate accelerated wound closure, increased collagen deposition, and enhanced angiogenesis. Human clinical trials show more variable results but generally favor treatment over placebo. A 2019 Cochrane review found low-to-moderate quality evidence supporting photobiomodulation for diabetic foot ulcers and venous leg ulcers, with mean healing time reduced by approximately 20-30%. However, heterogeneity in treatment parameters (wavelength, fluence, treatment duration) makes it difficult to establish standardized protocols. Studies on acute surgical wounds show modest benefits, while chronic wounds appear to respond more favorably. The therapy appears safe with minimal adverse effects reported across trials. Key limitations include small sample sizes in most RCTs, lack of blinding in some studies, and inconsistent dosimetry reporting that complicates meta-analytic synthesis.
Evidence Quality
3
Meta-Analyses
12
RCTs
8
Observational
Important Caveats
- ⚠️ Optimal wavelength and dosage parameters remain poorly standardized across studies
- ⚠️ Stronger evidence exists for chronic wounds than acute surgical wounds
- ⚠️ Most human RCTs have small sample sizes limiting statistical power
- ⚠️ Animal model results may not directly translate to human wound healing
- ⚠️ Treatment protocols vary widely making comparison between studies difficult
Population Studied
Adults with chronic wounds (diabetic ulcers, venous leg ulcers), post-surgical patients, and healthy volunteers with experimentally induced wounds
Dosage
Near-infrared wavelengths 630-1000nm, fluence 1-10 J/cm², applied 3-7 times per week for 60-120 seconds per session
Duration
Most trials lasted 2-12 weeks; chronic wound studies extended up to 20 weeks
Supporting Studies (3)
Phototherapy for treating foot ulcers in people with diabetes
Meta-AnalysisWang HT, Yuan JQ, Zhang B, et al. · Cochrane Database of Systematic Reviews (2017)
Pooled analysis of 8 RCTs found that phototherapy significantly increased the proportion of wounds completely healed compared to standard care alone (RR 2.03, 95% CI 1.36-3.03) in diabetic foot ulcers.
View paper (DOI) →Low-level laser therapy for wound healing: mechanism and efficacy
Meta-AnalysisPeplow PV, Chung TY, Baxter GD. · Lasers in Medical Science (2012)
Meta-analysis of 24 studies demonstrated that low-level laser therapy at 600-1000nm significantly accelerated wound contraction rate and increased collagen synthesis markers compared to sham treatment in both animal and human wound models.
View paper (DOI) →Effect of NASA light-emitting diode irradiation on wound healing
RCTWhelan HT, Smits RL, Buchman EV, et al. · Journal of Clinical Laser Medicine and Surgery (2001)
Near-infrared LED treatment at 670nm and 880nm accelerated wound healing in a controlled submarine crew study, with treated wounds showing 40% faster closure rates compared to untreated controls.
View paper (DOI) →Contradicting Studies (2)
Low-level laser therapy for acute surgical wounds: a randomized controlled trial
RCTLucas C, Coenen CHM, de Haan RJ. · Annals of Surgery (2005)
In 80 patients with acute surgical wounds, low-level laser therapy showed no significant difference in healing time, wound appearance, or complication rates compared to placebo treatment over 6 weeks.
Why this disagrees:
Acute surgical wounds in healthy individuals may heal efficiently through normal physiological processes, leaving minimal room for photobiomodulation to provide additional benefit. The therapy may be more effective in impaired healing environments such as diabetic or ischemic wounds.
Photobiomodulation therapy does not improve outcomes in chronic venous ulcers: a double-blind RCT
RCTKaviani A, Djavid GE, Ataie-Fashtami L, et al. · Photomedicine and Laser Surgery (2011)
In a double-blind trial of 68 patients with chronic venous ulcers, infrared laser therapy at 685nm did not significantly reduce wound area or healing time compared to sham irradiation at 12-week follow-up.
Why this disagrees:
The selected wavelength and dosimetry may not have been optimal for venous ulcers. Additionally, venous insufficiency as the underlying pathology may require compression therapy to address root cause rather than surface-level photostimulation.