Red Light Therapy for Bedsores: Scientific Evidence

Across 5 studies with 207 participants, a 2020 systematic review examined photobiomodulation for bedsores in adults and older people. The reviewed studies used wavelengths from 487 to 990 nm, spanning blue through near-infrared light, at an irradiance of 100 mW/cm² and doses mostly from 1 to 6 J/cm², given 3 to 7 times a week for 3 to 6 weeks. Photobiomodulation appeared to support bedsore repair across the studies reviewed, though the review authors noted considerable variation in study quality and laser settings, which limited firm conclusions.

8 patients (mean age 62) with severe (grade III-IV) bedsores took part in a 2018 clinical trial measuring how low-level laser therapy affected wound-repair activity at the cellular level. Patients had bedsores on the lower back/tailbone area and heel treated with a diode laser emitting 660 nm red light at 100 mW and a fluence of 2 J/cm² for 12 seconds per session, 12 times a week for 12 days, with tissue samples taken from the wound edge before and after treatment for lab analysis. Laser treatment appeared to shift the activity of several signaling proteins involved in inflammation and tissue repair in the wound tissue, consistent with a supportive role in the bedsore healing process.

19 children (ages 3 to 15, 7 boys and 12 girls) with meningomyelocele-related paresis took part in a 2016 clinical trial measuring the effect of laser therapy on skin blood flow, of whom 9 (47.3%) had bedsores in the affected area. Children received a single application of 680 nm red light at 60 mW and a fluence of 0.5 J/cm² to the affected skin just before blood flow was measured with a radioactive tracer test. Skin blood flow appeared to rise substantially after treatment across the tested children, from a group average of about 7.5 to 11.1 mL per 100 g of tissue per minute, though the study measured blood flow rather than bedsore closure directly and did not report on wound healing itself.

Comparing daily polarized light treatment against standard prevention alone, a 2007 randomized controlled pilot trial tested whether light therapy could prevent bedsores in an adult intensive care unit. 10 patients received 10 minutes of polarized light (480-3400 nm) daily to the lower back and both heels, starting the day after admission, while 13 patients received standard prevention only. Patients receiving polarized light appeared to develop significantly fewer new bedsores of grade II or worse than those in the standard-prevention group, though the researchers called for further research to confirm the finding.

Pooling data from 163 patients across 2 randomized controlled trials, researchers in 2007 confirmed earlier findings on monochromatic pulsed light therapy for grade II bedsores. Elderly patients received light at 637 and 956 nm at irradiances of 2.1 and 5.5 mW/cm² to the trunk and foot, or a placebo, in sessions of 6 to 9 minutes given 30 times a week for up to 12 weeks, using the same protocol as the earlier trial. Researchers found that bedsore size fell by a mean of 79% in the treated group compared with 50% in the placebo group by week 12, a statistically significant difference, with no serious side effects reported.

74 elderly patients with bedsores (also known as pressure ulcers) took part in a 2001 randomized controlled trial of pulsed red and near-infrared light in Sweden. Patients receiving standard ulcer care were also treated with pulsed light at 637 nm (red) and 956 nm (near-infrared) at irradiances of 2.1 and 5.5 mW/cm², applied close to the skin for 9 minutes a session, 5 times a week, for up to 10 weeks. Bedsores appeared to heal 49% faster in the light-therapy group than in controls, reaching 50% and 90% wound closure sooner, and average wound size fell to 10% of its original size by 5 weeks, compared with 9 weeks for the control group.

Wavelengths of 940, 808, and 658 nm were tested against sham light in a 2018 randomized controlled trial examining how laser therapy affects wound-repair signals in bedsores in Poland. 67 patients received basic wound care plus daily laser sessions 5 times a week for 1 month at their assigned wavelength and a dose of 4 J/cm², or sham treatment with the device turned off. The trial found that the 658 nm wavelength calmed inflammation-related signaling proteins and boosted a protein linked to new blood-vessel growth within the first 2 weeks, while the 940 and 808 nm wavelengths produced smaller, slower changes in these same signals, which the researchers linked to the weaker healing results seen at those wavelengths.

Across 4 randomized studies with 210 participants, a 2017 systematic review examined low-level laser therapy for bedsores. The included trials tested single wavelengths from 904 to 658 nm and multi-diode probes, at doses reported from 1 to 70 J/cm², in sessions from 60 seconds to 30 minutes, up to 12 times a week. Laser light at 658 nm was linked to a significant 71% reduction in bedsore area and complete healing in 47% of cases after 1 month. At the end, the review authors reported that no benefit was found for wavelengths above that or when light was delivered through a multi-diode cluster probe.

Wavelengths of 940, 808, and 658 nm were compared against placebo in a 2013 randomized controlled trial of laser therapy for stage II and III bedsores in Poland. 72 patients were split into 4 groups of about 18, receiving daily laser sessions to the legs, feet, ankles, and hip area 5 times a week for 1 month at an irradiance of 200 mW/cm² and an average dose of 4 J/cm², with a placebo group receiving an inactive device. The trial found that bedsores healed well with the 658 nm red light, while the 808 and 940 nm near-infrared wavelengths showed no clear effect in this study.

No significant reduction in wound size followed treatment with a 4-wavelength LED device compared with a sham device in a 2024 double-blind randomized controlled trial of grade 2 bedsores. 38 patients with bedsores on the lower back received either the active LED device, emitting 460 nm (blue), 595 nm (amber), 630 nm (red), and 850 nm (near-infrared) light at an irradiance of 90 mW/cm² and a fluence of 135 J/cm², or an identical-looking sham device, 3 times a week for 4 weeks. The trial found a significant increase in the thickness of the outer skin layer with LED treatment, but did not find a statistically significant difference in wound size between the LED and sham groups, particularly among wounds still covered by dead, hardened tissue.

Whether low-level laser therapy could help fight infection in bedsores was examined in a small 2018 observational study in Poland. 6 patients with stage II-III bedsores had wound swabs and blood tested for bacteria and for a natural antimicrobial protein made by the immune system, both before treatment and after 2 weeks of an 830 nm (near-infrared) laser treatment given for 60 seconds to 2 minutes per session, 10 times a week, at a fluence of 2 J/cm², and their results were compared with a separate group of 12 people without bedsores who were swabbed and tested once, without receiving laser treatment. The mix of bacteria in the wounds shifted over the 2 weeks but did not clearly point to a laser effect on infection, though blood levels of the antimicrobial protein fell significantly in most of the treated patients, which the researchers suggested may reflect a calming effect on inflammation rather than a direct effect on bacteria.

34 people with spinal cord injury and 64 bedsores took part in a 2004 randomized controlled trial of multiwavelength light therapy in India. The treatment group received 14 sessions of light from 46 probes at various wavelengths to the lower back, hip, buttocks, ankle, elbow, sit bone, and heel areas, delivering 4.5 J/cm² over 60 seconds per session, 3 times a week, while the control group received sham treatment. Overall healing did not differ significantly between the treatment and control groups, though the researchers concluded that deeper, stage 3 and 4 bedsores appeared to progress to a shallower stage faster with active light therapy.

164 patients with grade II and III bedsores took part in a 2003 multi-site randomized controlled trial of pulsed monochromatic light therapy. Patients received light at 637 nm (red) and 956 nm (near-infrared) at irradiances of 2.1 and 5.5 mW/cm², or a placebo device, over the wound, close to the skin, in sessions of 6 to 9 minutes given 30 times a week, for up to 11 weeks. No overall benefit appeared in the full study group, though grade II bedsores showed a trend toward better healing with light therapy, and patients with a lower body weight showed a significantly larger reduction in bedsore size with the active treatment.

A 2003 multicenter randomized controlled trial in the Netherlands tested low-level laser therapy as an add-on to standard care for stage 3 bedsores. 86 patients were enrolled, with 39 receiving near-infrared laser light at 904 nm to the buttocks, tailbone, heel, ankle, hip, and knee area at a dose of 1 J/cm² for 2.08 minutes per session, alongside standard care, and 47 receiving standard care alone, 5 times a week for 6 weeks; 79 patients had usable outcome data at the end of the study. The trial found no significant difference in wound-size reduction between the laser and standard-care-only groups. At the end of the study, the researchers concluded that the data did not support using laser therapy as an addition to standard bedsore care.