Does Red Light Therapy Work?

During red light therapy, tissue absorbs the light, which causes heat. Heating the tissues leads to vasodilation — widening of the blood vessels — which increases oxygen and blood supply. Some studies demonstrate that the penetration of red light also affects nerve conduction, providing pain relief. Others show increases in protein and glycogen synthesis, the stimulation of cell growth, and the formation of new blood vessels.

Researchers have studied the effects of red light therapy across many areas. Research indicates that red light therapy can promote cell repair in the brain by stimulating cellular mitochondria to prevent cell death after a brain injury or stroke. It may also relieve pain from trigeminal nerve neuralgia and neuropathic pain.

Red light therapy may also be effective at treating skin conditions. Studies show that it can increase cell proliferation and tissue restoration following burns and diabetic foot ulcers. It may also help treat pemphigus vulgaris, a chronic disease that causes blisters, though this study was limited to 10 patients. Red light therapy may also stimulate hair growth — limited studies recently showed it may be effective for regrowing hair after chemotherapy, though, again, more research is needed in this area.

Though there is no consensus about whether red light therapy is safe or effective at treating cancer, it may help with complications of cancer treatment. Studies show that red light therapy is a suitable treatment for breast cancer lymphedema, reducing inflammation and promoting the regeneration of lymph vessels, with some evidence that it is more effective than compression. The therapy may also improve inflammation and ulcers in the mouth related to chemotherapy and skin inflammation after radiation therapy.

Some studies show that red light therapy effectively treats some bone and joint conditions. Although these studies are limited, they demonstrate effectiveness at promoting closed bone fracture healing and improving tendon repair effectiveness. Red light therapy may also relieve symptoms of carpal tunnel syndrome by promoting nerve regeneration and improving the vascular supply.

Studies into the efficacy of red light therapy have been going on for about 50 years, though the treatment is still not widely accepted by the scientific and medical communities. This unacceptance is largely due to a lack of understanding about how or why the therapy works. One theory is that light causes an increase in electron transport, which stimulates cellular mitochondria. Another is that the light activates ion channels that allow calcium to enter the cells.

There are various techniques for red light therapy treatments. It can be administered as either a continuous wave or pulsing light. A single treatment typically lasts 30 to 60 seconds, and multiple treatments may be needed depending on the condition. One of the reasons red light therapy is not widely accepted is that it is ineffective unless performed using the right parameters. If the dose is too high or too low, the treatment session is too long or short a time, or there are too many or not enough repetitions, it produces inhibitory effects.

The effectiveness of red light therapy results from how it impacts cells, which includes reducing inflammation, cytoprotection against toxicity, and proliferation of multiple cells to encourage growth and healing. Red light therapy also affects the synthesis of proteins like collagen and those found in connective tissue, cartilage, and bone. Stem cells are sensitive to red light therapy and respond with increased migration, differentiation, and viability.

Red light therapy also has effects on tissue. It encourages muscle recovery, relieves pain by blocking the conduction of nerve fibers and releasing endorphins, and promotes the recovery of peripheral nerves after injury. One study shows that red light therapy improved memory and spatial learning in mice, and others indicate that it can directly stimulate bone formation.

Although the scientific community as a whole has not embraced red light therapy as a treatment, some studies highlight its potential. Despite these positive results, however, there is a lack of consistency concerning treatment standards, including the wavelength, duration of treatment, and coverage area. While the general opinion toward red light therapy is improving and it looks promising for the future, more research is warranted.