Miranda M.B. et al. - LED Photobiomodulation and Chronic Lower Limb Wounds: A Systematic Review

This systematic review of 6 randomized trials suggests that LED photobiomodulation, at wavelengths between 620 and 950 nm, may reduce the surface area of chronic lower-limb wounds, particularly in diabetic foot ulcers. One high-dose trial (126 J/cm²) showed no benefit, and the certainty of the evidence is considered very low.

What this study measured

Miranda’s team at the Federal University of the Parnaíba Delta in Brazil searched PubMed, Scopus, Web of Science, and Embase through May 2026. The objective was twofold: to synthesize randomized clinical trials on light-emitting diode photobiomodulation for chronic lower-limb wounds, and to identify the irradiation parameters associated with the best outcomes.

Chronic leg and foot ulcers represent a significant clinical and economic burden, characterized by slow healing and frequent recurrence. The authors present LED as a noninvasive and inexpensive option, although the clinical evidence for it remains inconsistent.

Key Findings

The dataset is small, but it provides dosimetry data that are rarely compiled.

• 6 randomized clinical trials were included.
• Wavelengths ranging from 620 to 950 nm.
• Energy densities ranging from 2.4 to 126 J/cm².
• Reported effects: reduction in wound area, improvement in wound bed quality, and increased microcirculation, particularly in diabetic foot ulcers.
• A trial using 126 J/cm² showed no beneficial effect, suggesting a dose-dependent response.
• Overall certainty of the evidence, as assessed by the GRADE method: very low.

How photobiomodulation works for this indication

In chronic wounds, the most commonly cited mechanistic hypothesis is the absorption of red and near-infrared light by mitochondrial chromophores, followed by modulation of inflammation and support for angiogenesis and fibroblast activity. The increase in microcirculation reported in some trials supports this hypothesis.

The review primarily highlights the concept of a dose window: trials at moderate energy densities report effects, whereas the trial at 126 J/cm² shows none. The authors view this as a possible biphasic response, though they are unable to demonstrate it based on just six trials.

Limits You Should Know

The very low certainty is due to the inconsistency of results across trials and their indirect nature. The radiation exposure parameters are highly heterogeneous, the sample sizes are small, and methodological limitations have been identified. No quantified average effect is reported in the summary.

The negative result of the high-dose trial should be noted: it indicates that the effect of LED does not persist at all doses. The authors conclude that these limitations preclude any definitive conclusions regarding clinical efficacy, despite the fact that the drug appears to be safe to use.

What This Means in Practice

For a person living with a leg ulcer or diabetic foot, LED is not a substitute for glycemic control, offloading, local care, or vascular management. It is considered a complementary treatment whose benefits have yet to be confirmed.

For clinicians, the useful contribution of this review is the mapping of parameters: 620 to 950 nm and 2.4 to 126 J/cm², with an adverse signal at the highest dose. The authors call for randomized trials with standardized protocols and dose comparisons before any recommendations are made.

Frequently Asked Questions

Does LED light help heal a diabetic foot ulcer?

According to this review of 6 randomized trials, LED may reduce wound area and improve microcirculation, particularly in diabetic foot ulcers, but the certainty of the evidence is very low. Diabetes management and wound care remain essential.

What light intensity is used in chronic wound trials?

The included trials used wavelengths ranging from 620 to 950 nm and energy densities ranging from 2.4 to 126 J/cm². The trial at 126 J/cm² showed no benefit.

Is LED photobiomodulation safe for chronic wounds?

The authors note that LED appears to be safe in the studies analyzed, while emphasizing that the data remain limited and heterogeneous.

Reference

Miranda MB, Barros ACS, de Paula AVL, Alves RF, da Rocha RB, Cardoso VS. Clinical dosimetry and efficacy of LED photobiomodulation for chronic lower-limb wound healing: a systematic review of randomized trials. Lasers Med Sci, 2026, 41(1). PMID 42315692. View the record on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.