Red Light Therapy for Surgical Wound Healing: Scientific Evidence

According to a 2023 observational study in Iran, researchers compared red laser therapy against conventional wound care for the surgical wounds of 40 women recovering from cesarean section. Women in the treatment group received red laser light at 658 nm, delivering a dose of 2 J per square centimeter over sessions lasting 5, 9, 15, or 40 minutes, while the comparison group used conventional wound care such as ointments and pain medication, with the surgical wound scored on a standard tool assessing redness, swelling, bruising, discharge, and wound-edge closure on the third, seventh, and tenth days after delivery. Surgical wound healing scores were found to be significantly better in the laser-treated group at all 3 follow-up points, with the average wound score at 10 days roughly half that of the comparison group, and pain ratings also favored the laser-treated group.

Complete closure of a reopened, infected surgical wound followed combined red laser therapy and a gel made from a Brazilian plant extract, according to a 2021 clinical trial case report of a woman recovering from a tummy-tuck procedure. She received red laser light at 625 nm, delivering a fluence of 4 J per square centimeter, once a week, alongside daily application of the plant-extract gel, after surgical removal of dead tissue from the wound. The wound appeared to fully close after 84 days of this combined treatment, though the researchers described this as a single-patient case report rather than a controlled study.

Published in 2019, this randomized controlled trial in Egypt compared laser therapy, trunk-stabilizing exercises, and standard cardiac rehabilitation alone for breastbone surgical wound recovery in 45 men aged 45 to 65 years after heart bypass surgery. The laser group received red light at 660 nm, delivering an irradiance of 100 mW per square centimeter and a fluence of 6 J per square centimeter, in 8-minute sessions, over 12 sessions across 4 weeks, in addition to the standard rehabilitation program given to all 3 groups. The laser group appeared to show a significantly greater narrowing of the gap in the surgical wound than the exercise or standard-care groups, along with a bigger drop in reported pain.

In 2018, a randomized controlled trial in Egypt tested pulsed high-intensity laser therapy on the surgical wounds of 40 women, aged 28 to 38 years, with diabetes and delayed cesarean-section healing. Half the women received near-infrared laser light at 1064 nm for 8 minutes per session, 3 times a week for 6 weeks, alongside standard diabetes and wound care, while the other half received sham laser treatment with the same standard care. Surgical wound size and appearance, scored on a standard scoring tool for how a wound is healing, appeared to improve significantly more in the laser-treated group than in the sham group.

A 2018 randomized controlled trial in Iran tested red laser therapy on skin-graft donor sites in 11 patients with grade 3 burn ulcers, comparing 18 donor-site areas split into a laser-treated half and an untreated half. The laser side received red light at 655 nm, an irradiance of 600 mW/cm², and a fluence of 2 J/cm², with healing assessed at 4 and 8 days after grafting. Specific measured healing outcomes were not available in the retrieved study text, so whether the laser-treated side healed differently from the untreated side cannot be reported here.

No significant difference in wound-closure scores followed red LED light therapy compared with a placebo device in a 2018 randomized, placebo-controlled, double-blind trial of 40 patients recovering from vein-graft harvesting for heart bypass surgery. Half the patients received red LED light at 640 nm, delivering an irradiance of 39 mW per square centimeter and doses of 1.06 and 6 J per square centimeter, in short daily sessions of 2.53 minutes over 4 days on the leg surgical wound, while the other half received a placebo LED device. The LED-treated group showed significantly less bruising and skin redness around the surgical wound than the placebo group. No cases of wound reopening occurred in the treated group, though the specific wound-closure scores assigned by evaluators did not differ significantly between the 2 groups.

A dose of 6 J per square centimeter of red laser light was tested against a placebo laser in a 2018 randomized, placebo-controlled, double-blind trial of 40 patients recovering from vein-graft harvesting for heart bypass surgery in Brazil. Half the patients received red laser light at 660 nm, delivering an irradiance of 1050 mW per square centimeter, applied to the incision in short daily sessions of 5.7 seconds over 4 days, while the other half received a placebo laser. The treated group appeared to have a significantly smaller area of bruising and skin redness around the surgical wound, along with better wound-edge closure, than the placebo group.

According to a 2017 clinical trial in Egypt, researchers compared low-level laser therapy against pulsed electromagnetic field therapy, a separate treatment that uses electromagnetic pulses rather than light, with both applied directly to the surgical wound of 50 patients recovering from appendix removal surgery. Blood samples were tested before and after 6 days of twice-daily treatment for changes in cell-signaling activity linked to tissue repair, and both treatments increased this activity, with the electromagnetic field treatment activating more of the signaling pathways measured than the laser did, leading the study authors to describe it as having a stronger healing effect. This signaling activity was measured in general blood samples rather than in the wound tissue itself, however, and the study did not report the surgical wound's actual size, closure, or healing time, so it offers indirect evidence about the treatments' biological effects rather than a direct reading of the wound's healing.

In 2017, a randomized controlled trial in Russia tested red light therapy applied to the surgical wound bed of 263 patients during gallbladder removal surgery. Patients in the treatment group had the surgical wound bed and surrounding tissue irradiated for 2 minutes during surgery with pulsed red LED light at 625 nm, delivering an irradiance of 15-30 mW per square centimeter and a fluence of 0.9-1.8 J per square centimeter, while the control group received no light treatment. Blood tests taken 3 days after surgery appeared to show a significantly smaller rise in blood markers of liver stress and inflammation in the light-treated group compared with the control group, with only a small increase in overall surgery time.

Researchers tested laser therapy on the surgical wound in 85 patients undergoing weight-loss surgery, in a 2016 randomized controlled trial with a placebo-controlled design in Brazil. 43 patients received near-infrared laser light at 808 nm at 10 points along the incision over 3 sessions across 7 days, delivering an irradiance of 495 mW per square centimeter and a fluence of 10 J per square centimeter, while 42 patients received the same treatment with the laser switched off. The treated group was found to have lower wound temperature and lower levels of a blood marker of inflammation than the placebo group, alongside better surgical wound healing, less fluid buildup under the skin, and reduced pain.

A 2016 randomized, double-blind controlled trial in Brazil tested red laser therapy on the breastbone surgical wound of 90 patients recovering from open-heart surgery, divided equally into control, placebo, and laser groups. Patients in the laser group received red light at 660 nm, delivering an irradiance of 100 mW per square centimeter and a fluence of 1.06 J per square centimeter, in 60-second sessions on postoperative days 2, 4, 6, and 8. Incision photographs taken at hospital discharge, assessed by evaluators unaware of each patient's group, appeared to show significantly less skin redness, bleeding, and wound reopening in the surgical wounds of the laser-treated group than in the control and placebo groups.

14 patients recovering from vein-graft harvesting for heart bypass surgery appeared to show clear surgical wound improvement after infrared laser therapy in a 2014 clinical trial in Brazil. 7 patients received an infrared diode laser at 780 nm, delivering an irradiance of 625 mW per square centimeter and a fluence of 19 J per square centimeter over 30 seconds per point, applied along the edges of the incision, while the other 7 received standard care alone. All 7 patients in the laser group showed improvement in the surgical wound, while the standard-care group had roughly twice as many wound complications, including serious incision breakdown.

Across 360 patients undergoing stomach and bowel surgery, a 2013 randomized controlled trial in Switzerland tested a single preoperative dose of water-filtered infrared A light to prevent surgical wound infection. Patients received either 20 minutes of water-filtered infrared A light at wavelengths of 590-780 nm and 590-1400 nm, delivered at an irradiance of 200-225 mW per square centimeter, plus visible light, or a placebo light, to the skin over the planned surgical wound site just before their operation. Surgical wound infections were found to be significantly less common in the group that received infrared light in the main analysis, and this group also reported less pain in the 30 days following surgery, though the difference in infection rates was smaller and not statistically significant when all enrolled patients were counted.

Applying red and near-infrared light to both the wound and the shoulders rather than the incision alone, a 2013 clinical trial in India treated a diabetic patient's long-standing reopened surgical wound after heart bypass surgery. The patient received light at 660 nm and 950 nm, delivered at an irradiance of 50 mW per square centimeter and doses of 4 and 14 J per square centimeter, in daily sessions of 4 and 11.67 minutes over 11 days. Healthy new pink tissue appeared to grow in and close the surgical wound gap, scores on a standard scoring tool for how a wound is healing steadily improved, and pain in the shoulders and at the incision both eased, though this was a single-patient case rather than a controlled study.

Among 36 newborns who underwent spinal-defect repair surgery immediately after birth, a 2010 clinical trial in Brazil tested low-level laser therapy for their surgical wounds. 13 newborns received red laser light at 685 nm, delivering 4 to 10 joules of energy per patient along the surgical incision, in addition to standard care, and their outcomes were compared with 23 newborns from an earlier group who received standard care alone. Surgical wound breakdown occurred significantly less often in the laser-treated group (7.69% versus 17.39%), and the researchers concluded the treatment was safe and supported surgical wound healing.

Comparing an infrared diode laser against no treatment, researchers in Brazil ran a 2010 randomized controlled trial on surgical wound scars following hernia surgery, enrolling 28 patients. Half the patients received an 830 nm infrared diode laser applied directly to the healed incision at 4 sessions over the first week after surgery, delivering a dose of 13 J per square centimeter over 26 seconds per point each time, while the other half received no laser treatment. Surgical wound scars in the laser group were found to score significantly better on a standard scale for rating scar appearance, were thinner and more flexible, and patients reported roughly half the pain reported by the untreated group, 6 months after surgery.

Researchers tested whether low-level laser therapy could speed surgical wound healing without disrupting breastfeeding in a 2009 randomized controlled trial of 20 women scheduled for cesarean section. Half the women received laser light at 980 nm, delivering a fluence of 3.3 J per square centimeter, and 650 nm, delivering a fluence of 1.5 J per square centimeter, applied to the surgical incision line, plus laser light at 650 nm delivering a fluence of 0.15 J per square centimeter delivered into a vein for 15 minutes on 3 days after surgery, while the other half received no laser treatment. Blood levels of a hormone linked to milk production did not differ significantly between the 2 groups, but tissue samples from the surgical wound edge showed significantly more new blood vessel growth in the laser-treated group, leading the researchers to conclude the treatment supported wound healing without harming lactation.

2009 brought a clinical trial testing low-level laser therapy for a reopened surgical wound at the leg incision site following heart bypass surgery. The patient received red light at 685 nm, delivered at a fluence of 4.5 J per square centimeter and a power of 20 mW, applied directly around the wound edges after standard treatment had failed to improve the surgical wound over the previous month. New pink tissue growth appeared in the wound along with less inflammation and less pain from the very first laser session, though this was a single-patient pilot case rather than a controlled study.

Researchers in Germany tested water-filtered infrared A light therapy, at wavelengths of 590-780 nm and 780-1400 nm, on surgical wound healing after abdominal surgery in a 2006 randomized controlled trial. 111 patients undergoing moderate to major stomach and bowel surgery received either water-filtered infrared A light plus visible light, or visible light alone, to their open surgical wounds for 20 minutes twice a day from day 2 to day 10 after surgery. Wound healing, judged on a standard visual rating scale, appeared better in the group receiving water-filtered infrared A light, with less pain, higher tissue oxygen levels, and higher tissue temperature in the treated group, according to both surgeons and patients.

84 women with surgical wound complications in the area between the vagina and anus following childbirth took part in a 1990 clinical trial comparing helium-neon (HeNe) laser therapy with an enzyme-based wound treatment. 69 women received red light at 632.8 nm from a helium-neon laser applied to the wound edges, while 15 women received a proteolytic enzyme solution with vitamin C instead. Tissue samples examined under the microscope showed more active early wound-repair activity and more advanced new pink tissue growth in the surgical wounds treated with laser therapy, pointing to a stronger healing response than the enzyme treatment produced.

A dose-ranging design tested helium-neon (HeNe) laser therapy at power densities from 50 to 100 mW per square centimeter in a 1989 clinical trial of 160 women, aged 26 to 58 years, with partially reopened surgical wounds after gynecological operations. Patients received red light at 632.8 nm, applied for 90 seconds per treatment field. Pain relief and reduced inflammation appeared fastest at 90 mW per square centimeter, and surgical wounds treated at power densities between 70 and 100 mW per square centimeter healed within 5 to 10 days, while the lowest dose tested was less effective.

This 1989 clinical trial tested helium-neon (HeNe) laser therapy on 97 surgical wounds that had failed to heal for 10 to 60 days despite standard antibiotic and antiseptic care, following gynecological abdominal surgery. Patients received red light at 632.8 nm at a power density of 70 or 90 mW per square centimeter, applied for 90 seconds per treatment field, over 5 to 18 sessions. These previously unresponsive surgical wounds went on to heal within 5 to 18 days of starting laser treatment, and the higher 90 mW per square centimeter dose was found to speed tissue repair more than the lower dose.

12 of 25 skin-graft donor sites received red LED light alongside standard dressing in a 2022 clinical trial in Brazil, while the remaining 13 received standard dressing alone, in patients recovering from burn injuries requiring skin-graft surgery, with a mean age of 36.8 years. Red LED light at 660 nm, delivering an irradiance of 2.55 mW per square centimeter and a fluence of 1.53 J per square centimeter, was given in 10-minute sessions over 5 sessions across 7 days. Surgical wounds treated with LED light scored more favorably on a standard scoring tool for how a wound is healing than untreated sites, with significantly less pain from the third day of treatment onward, though the improvement was described as partial rather than complete.

Among 141 women with fluid buildup, blood pooling, or infection near surgical wounds after gynecological operations, a 1989 clinical trial tested helium-neon (HeNe) laser therapy at power densities from 50 to 100 mW per square centimeter. Patients received red light at 632.8 nm for 90 seconds per treatment field, 1 to 3 times a week, depending on their group. Power densities of 70 to 100 mW per square centimeter were found to resolve these surgical wound complications within 1 to 6 days, while the lowest dose tested, 50 mW per square centimeter, was not effective, and deeper fluid pockets beneath the surgical layer did not resolve even at the highest dose.

63.2 days was the average healing time for surgical wounds treated with red LED light therapy, compared with 48.67 days for untreated wounds, in a 2020 randomized controlled trial of 14 patients with lower-leg surgical wounds left to heal without stitches. Patients received red LED light at 633 nm, delivering an irradiance of 105 mW per square centimeter and a fluence of 126 J per square centimeter, in weekly 20-minute sessions over 4 weeks. This difference did not reach statistical significance, and the researchers concluded that the treatment did not produce a clinically meaningful improvement in surgical wound healing.