Biphasic dose response in low level light therapy - an update.

Abstract in brief

• Low level laser light therapy (LLLT) has been around since 1967, but its mechanisms and optimal dosimetric parameters are still not fully understood, leading to some controversial and negative study results.
• The biphasic dose response, also known as the Arndt-Schulz curve, is observed in both lab and animal studies, meaning that both too little and too much light can be ineffective or harmful, with some indicators like reactive oxygen species showing complex triphasic patterns.
• Understanding and optimizing these dose-response patterns are crucial for improving clinical applications, such as transcranial LLLT for brain injury, where specific treatment doses can lead to maximal beneficial effects.]