Red Light Therapy for COVID-19: Scientific Evidence

Researchers in Brazil compared near-infrared LED light therapy against standard breathing physiotherapy for COVID-19 in a 2023 randomized trial. 30 hospitalized patients were divided between the 2 approaches, with the light group receiving 940 nm light in contact with the chest and abdomen for 15 minutes daily over 7 days, at 20 mW and 6 W, 2.9 mW/cm², 2.6 J/cm², and 5400 J across the course. The trial found the light group left hospital sooner and showed statistically significant gains in blood oxygen, breathing volume and strength, breathing rate, heart rate and blood pressure, alongside changes in white blood cell counts.

Across 3 treatment centers, a 2022 case series in Brazil described managing mouth and facial sores in patients with COVID-19 using a light-activated dye alongside photobiomodulation. Red and near-infrared light at 660 and 808 nm was applied at 40 and 100 mW to the nostril, the crease beside the nose, the lips, tongue, gums, and palate, in applications of 5 seconds to 2 minutes at 23 to 120 J/cm² and 0.4 to 4.8 J. The authors concluded that the dye can inactivate the virus while easing pain and encouraging healing, and described the approach as a supportive measure in severe cases.

A pilot protocol combined 3 treatments in a 2022 observational study in the Bahamas, pairing a light-activated dye applied in the nose and mouth with the same dye taken by mouth and with red light therapy for COVID-19. 8 patients received red light at 660 nm in contact with the nasal and oral cavities, under the tongue, over the salivary glands and at the throat, in applications of 60 seconds to 5 minutes at 81 to 163 mW/cm², 4.9 to 49 J/cm² and 732 mW to 2.93 W. Symptoms appeared to improve across the group, and patients were followed-up for 12 months afterwards.

3 markers of inflammation fell by 54% to 83% in the treated group in a 2022 randomized double-blind placebo-controlled trial of photobiomodulation (PBM) for mild to moderate COVID-19. 52 hospitalized patients in Iran were divided between real and placebo treatment, with red light at 620 to 635 nm applied in contact with the mid and lower back, both sides of the chest, and the neck over the main artery, for 6 minutes at 120 mW/cm² and 45.4 J/cm² across 3 days. A fourth marker did not change, and the placebo group showed no reduction at all, the researchers reported. No complications or after-effects from the treatment appeared during the study.

In 2022, a review from the United Kingdom set out the case for near-infrared light at 1068 nm as a non-invasive treatment for COVID-19 and other coronaviruses. The wavelengths it considered ran from about 900 to 1093 nm, applied to the nose, the chest, the brain, the skin and the main breathing muscle, over courses reaching about 150 days. The authors concluded that this particular wavelength may act through 2 of the body’s own protective mechanisms, and presented it as a candidate worth testing rather than an established treatment.

50 patients with confirmed COVID-19 took part in a 2022 case study in the United States using deep-tissue light therapy through the skin as their main or only treatment. Red and near-infrared light at 650 and 850 nm was alternated by the device and applied in contact with the sinuses and lungs at an average of 11 mW/cm² and 50 J/cm², in sessions of about 84 minutes delivering 15000 to 20000 J, over courses reaching 21 days. Relief of the sharpest symptoms appeared to come almost immediately regardless of how long a patient had been ill, while full recovery took considerably longer.

Pairing a light-activated dye with photobiomodulation, a 2021 case series in Brazil treated mouth and facial sores in 4 patients with COVID-19. Red light at 660 nm and 100 mW was applied in contact with the lip in applications of 5 to 40 seconds, at 33 J/cm² and 0.5 to 4 J, given daily. The combination appeared to help manage sores for which existing treatments have been inconsistent and of doubtful benefit.

2021 brought a case report describing photobiomodulation combined with a static magnetic field for lasting lung damage after COVID-19. A 53-year-old man received red and near-infrared light at 633, 850, and 905 nm in contact with the lower chest, upper abdomen, and neck for 8 minutes once a day across 45 days, at 3.91 to 71.23 mW/cm², 0.23 to 4.29 J/cm², and 1.25 mW to 50 W. The report found improvements in blood oxygen levels and lung function, alongside reduced scarring from the illness.

60% of untreated patients needed intensive care, and 40% died, compared with none of those given light, in a 2021 randomized trial of photobiomodulation therapy (PBMT) for COVID-19 pneumonia in Canada. 10 patients were randomly assigned, with the treated group receiving near-infrared light at 808 and 905 nm to the lungs from 7.87 inches away for 28 minutes daily over 4 days, at 610 mW and 1.5 W, 31 and 75 mW/cm², 7.18 J/cm² and 3590 J. Treated patients appeared to recover quickly, avoided intensive care and mechanical ventilation, and reported no lasting problems 5 months later, while 40% of the control group did.

A 57-year-old man whose severe COVID-19 pneumonia cleared in about 3 weeks received 4 once-daily photobiomodulation sessions in this 2020 observational study, the first reported use of the therapy in COVID-19. A laser scanner delivered near-infrared light at 808 and 905 nm to the lungs from 7.87 inches away, in sessions of 14 to 28 minutes at 33.75 mW and 1.5 W, 1500 Hz, 0.11 and 7.2 J/cm² and 1794 to 3600 J. Chest imaging, oxygen requirements, blood markers and patient questionnaires all supported the recovery, which ran shorter than the 6 to 8 weeks typical for the illness, the report noted.

When a 32-year-old woman with severe COVID-19 pneumonia and morbid obesity was not improving, a 2020 observational study in the United States added low-level laser therapy (LLLT) to her conventional care. A laser scanner delivered near-infrared light at 808 and 905 nm to the back of the chest from 7.87 inches away, for 28 minutes once daily across 4 days, at 33.75 mW and 1.5 W, 1500 Hz, 0.11 and 7.2 J/cm², and 3600 J in total. The report found improvement over a few days in breathing measures, chest imaging, and blood markers of inflammation.

Whether light therapy delivered at home can relieve the cognitive difficulties that persist after COVID-19 was tested in a 2026 randomized double-blind sham-controlled pilot trial. 43 adults aged 18 to 65 with symptoms lasting at least 12 weeks were randomly assigned, with 21 analyzed after receiving near-infrared light at 810 nm and 40 Hz through the nose and across the scalp for 20 minutes a day, 6 days a week over 8 weeks, and 20 receiving a sham device. The combined thinking-skills score did not improve significantly more than with sham, though attention tasks improved at several points and participants under 45 showed significant gains in a comparison the trial described as exploratory. Measures of mobility and fatigue favored the sham group instead. No serious adverse events occurred.

The length of intensive care unit (ICU) stay showed no significant difference between treated and placebo groups in a 2021 triple-blinded randomized trial of severe COVID-19 in Brazil. 30 patients on mechanical ventilation were randomly assigned to light therapy combined with a static magnetic field, delivered at 633, 850, and 905 nm over the main breathing muscle below the lungs for 8 minutes at 4 to 71 mW/cm², 0.95 J/cm², and 63 to 189 J, or to a placebo. According to the trial, secondary measures favored the treated group, which kept more thickness in that breathing muscle, took in oxygen more efficiently, and showed better inflammation and immune-cell readings, all statistically significant.

Across 552 patients drawn from the published literature, a 2021 systematic review from Brazil assessed photobiomodulation therapy (PBMT) as a possible approach to COVID-19. The studies it gathered applied ultraviolet, green, red, and near-infrared light at 365, 525, 662, 808, 904, and 905 nm to the back and lower chest, the neck, the mouth and nose, and the artery at the wrist, in sessions of 90 seconds to 30 minutes at 2 mW to 15 W and 0.01 to 40 J/cm². The review found that light therapy may raise immunity and support tissue repair in COVID-19, though it stopped short of pooling the studies into a single estimate.

A 2021 review examined whether photobiomodulation (PBM) could help severe COVID-19 by calming the immune overreaction that damages the lungs. The work it drew on used red and near-infrared light from 600 to 1000 nm, including 635 nm, at 1 to 5000 mW/cm² and 1 to 500 mW directed at the lungs. According to the review, light therapy has lowered 2 of the inflammatory signaling proteins that drive severe lung injury, so it could be effective in severe cases. The review set out a hypothesis rather than reporting results from patients.

According to a 2020 review from Australia, photobiomodulation could have a role in both treating and preventing COVID-19, particularly in older people and those with other health conditions. The approaches it surveyed applied red and near-infrared light at 640, 660, 670, 900 and 904 nm in contact with the gland behind the breastbone, the limbs, the forehead, the nose, the head, the mouth and the abdomen, for 10 to 20 minutes at 1 to 16 J/cm². The authors concluded that light therapy may calm an over-reactive immune response, while noting that treatment options for people with severe illness remain limited.

This 2020 review from Canada set out how low level laser therapy (LLLT) might be used to calm the runaway inflammation seen in severe COVID-19 and reduce the need for ventilators. The protocols it described delivered red and near-infrared light at 630 to 660 and 780 to 900 nm in contact with the nose, throat, windpipe, chest front and back, and the veins at the elbow, at 50 to 100 mW, 4 to 10 J/cm², and 5 to 10 Hz, in sessions of 1 to 15 minutes across 3 to 10 sessions. Light therapy appeared to carry anti-inflammatory effects that might help, though the review set out a rationale rather than reporting results from patients.