Red light therapy is generally low-risk when used correctly, but safety depends on dose, distance, eye protection, user condition, and device quality. The main risks include direct eye exposure, excessive irradiance, photosensitivity, poor documentation, and unsafe use around certain medical conditions.

Red light therapy is generally safe but carries narrow, dose-dependent risks. The biggest dangers are retinal injury from unprotected eye exposure, overexposure violating the biphasic dose-response, thermal effects from prolonged full-body sessions, and reactions in photosensitive users. Certified devices, proper irradiance matching, eye protection, and medical clearance minimize harm.