Red light therapy uses specific wavelengths of red or near-infrared light in an attempt to change how cells function. But has the consumer market grown faster than the scientific evidence?
“Right now, red light therapy from a musculoskeletal standpoint is still growing,” said Michael Giovanniello, a board-certified specialist in the field of physical medicine and rehabilitation, sports medicine, and pain medicine. He’s always interested in new methods of treatment, and red light therapy is one he’s kept tabs on for years.
“It's been approximately over the last seven to 10 years that it's gained more favor. But they've been doing studies with respect to red light therapy for various different health issues since the 1960s," he said.
The field began in 1967 when Dr. Endre Mester tested whether a low-powered red light laser could cause skin cancer in mice. He discovered that not only did exposed mice not have higher cancer rates, but their shaved hair grew back faster than expected, much faster than the un-lasered, untreated control mice. He attributed this to something he called "laser biostimulation," known today as red light therapy.
“Red light therapy, which scientifically is known as photobiomodulation, is basically using light to modulate biologic tissue," Giovanello said.
This process in itself is not a new concept. We’ve known for more than 100 years that ultraviolet light drives vitamin D production. Controlled doses of artificial ultraviolet light are used to treat psoriasis, and bright white light is a staple for seasonal affective disorder.
So, what about red light? Can it be used in a clinical setting?
“As a provider right now, what we're saying is we are going to use it as an adjuvant to a structured program," Giovanello said. "So, we can use it as a modality, as a tool in the toolbox, but it's not a standalone treatment.”
Red and near-infrared wavelengths can penetrate the skin and be absorbed by cells. The current understanding is that this light helps the mitochondria. They’re the powerhouses of the cell that convert energy in glucose into a form that cells can actually use.
However, other studies found that even if the mitochondria are inhibited, health benefits remain. Still additional studies have found that red light therapy influences circulation, inflammation, and even tissue repair.
“One of the big things is with regard to wound healing, and then ultimately with respect to chronic musculoskeletal injuries, things that typically don't heal the way we would like,” Giovanello said.
But the strength of the evidence varies considerably by condition. It’s possible red light therapy may be beneficial for damaged cells but have little to no measurable impact on healthy cells.
The general consensus among researchers is that some existing studies are promising. However, many have included few participants, lacked placebo groups, or were conducted only in animals or isolated cells.
A recent article in Nature emphasized another major problem: standardization.
“So, all red light therapy is not equal," Giovanello said. "What's the appropriate wavelength, what's the appropriate dose and for how long, what's the timing? That's what we have to dial in better.”
This is an area of active research. Numerous recently completed, ongoing, and proposed studies on red light therapy exist. They cover everything from treating Parkinson's disease to modulating blood-sugar levels to influencing the quality of embryos produced through in vitro fertilization. Many do not yet have conclusive evidence of the efficacy of red light therapy.
However, that hasn’t stopped the consumer market from producing masks, panels, and other devices. Many of them have not been extensively or independently tested.
These easily accessible products often use so little power it’s unlikely they would cause any negative effects. On the other hand, that could also mean they’re unlikely to have any positive effects as well.
Claims, prices, wavelengths, builds, and rigor all vary widely by product. Some retail for as little as $10, while others reach into the tens of thousands.
Regardless, Cleveland Clinic warns that improper use may damage the skin or eyes, and the long-term safety of repeated use is not yet known.
Overall, Giovanniello says the marketing has moved faster than the evidence.
“There's a lot of hype. But it's not a magic bullet. It's not a panacea," he said. "It needs to be used in the framework of a structured program.”
Giovanniello recommends first getting a diagnosis and using red light only as part of a broader treatment plan, especially for people with muscle or tendon injuries. He says physical therapy, movement, and controlled exercise remain the foundation of recovery. Red light may help reduce pain or support healing, but it cannot replace rehabilitation.
