How did red light therapy begin?

Red light therapy began not as a wellness trend for skin rejuvenation or muscle recovery, but as a serious medical investigation into wound healing and pain management. Following Endre Mester’s 1967 discovery that low-level laser light accelerated hair growth and wound closure in mice, the initial applications were strictly clinical and experimental. In the late 1960s and 1970s, researchers in Europe and the Soviet Union began applying these findings to human patients. The early focus was on treating non-healing ulcers, slow-healing surgical wounds, and severe burns. The logic was straightforward: if light could speed up cell division in mice, it could potentially rescue failing tissues in humans.

During the 1970s and 1980s, the therapy (then known primarily as Low-Level Laser Therapy or LLLT) gained traction in physical therapy and sports medicine clinics, particularly in Eastern Europe and Asia. It was used to treat musculoskeletal conditions such as tendonitis, arthritis, and back pain. The mechanism was believed to be the reduction of inflammation and the stimulation of ATP production, which provided cells with the energy needed to repair themselves. However, during this period, the technology was limited to low-power gas lasers (like helium-neon lasers), which were expensive, fragile, and could only treat very small areas at a time. This limitation kept the therapy niche; it was impractical for large-scale treatments like full-body recovery or extensive skin conditions.

The beginning of red light therapy was also marked by significant skepticism. Because the mechanisms were not yet fully understood (prior to Tiina Karu’s work in the 80s), many in the Western medical community viewed it as "quackery" or a placebo effect. The lack of standardized dosing protocols further hampered its adoption. Different clinics used different wavelengths, power outputs, and treatment times, leading to inconsistent results. Some studies showed miraculous healing, while others showed no effect, creating a confusing landscape for practitioners.

It wasn't until the development of Light Emitting Diodes (LEDs) in the late 1980s and 1990s that the therapy began to shift from small-spot laser treatments to broader applications. LEDs allowed for the creation of larger panels that could treat entire limbs or sections of the body simultaneously, without the coherence and speckle issues of lasers. This technological shift marked the transition from "laser therapy" to the broader concept of "photobiomodulation."

Initially, the therapy was almost exclusively the domain of doctors and physical therapists. There was no consumer market. The devices were bulky, cost thousands of dollars, and required trained operators. The "wellness" aspect—using red light for anti-aging, acne, or general vitality—was a much later development, emerging only after the safety profile was well-established and the technology became affordable enough for home use. Thus, red light therapy began as a gritty, experimental medical tool for saving limbs and healing deep wounds, far removed from the sleek beauty devices seen in spas today.