Photobiomodulation follows a biphasic dose-response curve, meaning more joules isn't always better — beyond an optimal window, response plateaus or reverses. This article explains the dose window, reciprocity failure between intensity and time, recognisable over-exposure symptoms, eye safety, and how credible red light panels are engineered for a reasonable target range rather than maximum output.

Red light therapy is generally safe with proper dosing (10–20 mins/session, 3–5x/week) and quality devices. Skin tone, device compliance, and avoiding overstimulation matter. It’s non-invasive but not risk-free—avoid if photosensitive or on light-sensitive meds; eye protection is recommended.