Red Light Therapy for Venous Leg Ulcer: Scientific Evidence

10 patients with 11 hard-to-heal venous leg ulcers, evenly split between men and women with a median age of 62, took part in a 2008 clinical trial of water-filtered infrared light. Patients received a water-filtered infrared lamp delivering light and heat spanning roughly 550 to 1400 nm at about 140 mW/cm², 2 to 5 times per week for 30 minutes per session, over up to 2 months. According to the study, 7 of the 10 patients achieved complete or near-complete healing and 2 more showed a clear reduction in ulcer size, alongside less pain and lower use of pain medication. The weakest results occurred in patients who smoked, had poor circulation in the leg arteries, or skipped compression-garment therapy.

57% of venous leg ulcer wound area shrank on average after light therapy in a 2003 clinical trial. 25 patients with venous leg ulcers received daily sessions of polarized, multi-wavelength light spanning roughly 480 to 3400 nm, at an irradiance of 40 mW/cm² and a fluence of 19.2 J/cm², for 8 minutes a day over 4 weeks. Researchers found that the number of ulcers fell from 73 to 51 over the 4 weeks, with a statistically significant average wound-area reduction of 57%, and nearly all treated ulcers showed some improvement, though the authors recommended a randomized controlled trial to confirm these findings.

A 1999 clinical trial in the United States tested near-infrared light for healing hard-to-heal wounds that had not responded to standard care, including venous leg ulcers. Patients received an infrared light device cleared for sale in the United States, delivering 890 nm near-infrared light to venous leg ulcers, foot wounds related to diabetes, and a wound linked to scleroderma. The trial reported that these previously unresponsive wounds appeared to heal faster and more completely after the infrared treatment, an effect the researchers linked to higher levels of a blood-vessel-widening molecule in the treated tissue, though they called for further research to confirm the finding.

9 patients with 12 venous ulcers took part in a 1998 randomized, placebo-controlled trial of low-energy photon therapy (LEPT), a red-and-infrared light treatment. Ulcers received red light at 660 nm and near-infrared light at 880 nm from 2 light probes sized to cover the wound, 3 times a week for 10 weeks, while placebo patients received an identical-looking inactive device. The share of the original ulcer area still unhealed by the end of the study was far smaller with active treatment than with placebo (24% versus 85%), and the reduction in ulcer size was likewise much larger with active treatment. No harmful side effects were reported during the study. 1 patient dropped out during the study, citing a lack of treatment effect, and was later found to have been randomized to the placebo group.

12 patients with venous leg ulcers that had not responded to conservative care took part in a 1990 clinical trial in Ireland of infrared laser therapy. Patients received near-infrared laser light at 780 and 904 nm, in sessions lasting 15 seconds to 20 minutes given 3 times a week, over a 12-week treatment course. 2 ulcers appeared to heal completely, and the remaining ulcers shrank by 27% on average, with a 44% increase in new healing tissue on the surface of the wound and a drop in reported pain from 7.5 to 3.5 on a standard rating scale, though the researchers called for larger randomized trials to confirm these early results.

Comparing water-filtered infrared light plus visible light against visible light alone, a 2011 randomized controlled trial tested at-home treatment for chronic venous leg ulcers. 51 patients used the light devices, spanning 380 to 780 and 780 to 1400 nm at irradiances of 45, 140, and 185 mW/cm², for 30 minutes, 5 times per week for 9 weeks, alongside compression therapy, wound cleansing, and non-stick dressings, then were followed for 4 more weeks without treatment. Healing scores on a standard 0-100 rating scale were higher in the infrared-plus-visible-light group than the visible-light-only group after 9 weeks (85 versus 67.5), and more patients in that group showed a healing trend (84% versus 50%) and better new-tissue growth in the wound, the researchers reported. The main combined measure of ulcer-area change over time did not reach statistical significance.

Across 4 randomized controlled trials with 139 participants, a 1999 meta-analysis in the United Kingdom examined low-level laser therapy for venous leg ulcers. The included trials used red and near-infrared lasers at wavelengths from 632.8 to 1400 nm, in sessions lasting about 10 minutes given 1 to 3 times per week for 4 to 39 weeks, at doses of roughly 2 to 10 J/cm². The review found no clear benefit of laser therapy alone over placebo or ultraviolet light for ulcer healing, though one trial reported more complete healing at 9 months when a helium-neon (HeNe) laser was paired with near-infrared light rather than ordinary red light, leading the authors to call for more research before drawing firm conclusions.

No improvement in wound closure, ulcer size, or pain followed low-level laser therapy (LLLT) compared with placebo in a 2017 double-blind randomized controlled trial of venous leg ulcers in France. 24 patients (ages 43 to 87, averaging 67, 11 male and 13 female) with venous leg ulcers 5 to 20 cm² in size and an average history of 6 weeks received 24 sessions of either red laser light at 635 nm, an irradiance of 2.46 mW/cm², and a dose of 2.95 J/cm², lasting 20 minutes each, or a placebo device, over 12 weeks. Researchers found that complete wound closure, final ulcer size, and pain scores did not differ significantly between the treated and placebo groups after 12 weeks, though pain briefly dropped more in the treated group during the first 4 weeks of the study.

No significant difference in wound-size reduction was observed following low-level laser therapy compared with placebo or standard care alone in a 2005 randomized controlled trial of venous leg ulcers. 44 patients were split into a laser group, a placebo-light group, and a standard-care-only group, all receiving standard wound dressing and compression bandaging, with the laser delivering 685 nm red light at a fluence of 4 J/cm², in sessions lasting 6 to 18 minutes given 21 times a week, and ulcer size measured at the start, after 4 weeks of treatment, and again 2 months later. The researchers concluded that low-level laser therapy did not stimulate wound healing beyond what standard care and placebo achieved on their own, though a placebo-related improvement appeared in some patients.

15 older adults averaging 70 years of age, most of them women, took part in a 2002 randomized, placebo-controlled trial of combined phototherapy and low-intensity laser therapy for chronic venous leg ulcers. Patients attended a weekly outpatient ulcer clinic and received either real or placebo treatment from a multi-wavelength LED device covering 660 to 950 nm (red to near-infrared), delivering a fluence of 12 J/cm², once a week for 4 weeks, alongside standard nursing wound care. Wound size did not differ significantly between the treated and placebo groups overall, though the treated group appeared to keep shrinking after treatment ended, suggesting a possible delayed benefit. Pain levels were similar between the 2 groups.

1991 brought a randomized controlled trial in Sweden testing whether a low-power helium-neon (HeNe) laser could speed the healing of chronic venous leg ulcers. 46 patients received standard compression bandaging plus either real HeNe laser light at 632.8 nm and a fluence of 4 J/cm², or a placebo laser, twice weekly for 12 weeks, with ulcer healing measured at 2, 4, 6, 8, and 12 weeks. The trial found no significant difference in the share of healed ulcers or in ulcer size between the real-laser and placebo groups at any time point.

Energy doses of 1 and 4 J/cm² from a helium-neon (HeNe) laser were tested against antiseptic compresses alone in a 1984 clinical trial of venous leg ulcers. 61 patients were split into 2 laser-dose groups and a control group, with the laser delivering 632.8 nm red light 6 days a week over 42 days (6 weeks), and the control group receiving only antiseptic local compresses. No statistically significant difference in healing turned up between either laser-dose group and the control group, and the researchers concluded that helium-neon laser treatment offered no advantage over standard local care at the doses tested.