The efficacy of low-power lasers in tissue repair and pain control: a meta-analysis study.This study shows Low-power phototherapy devices were first used as a form of therapy more than 30 years ago. More recent findings mandate the conclusion that phototherapy is highly effective for tissue repair and pain relief

Link: https://pubmed.ncbi.nlm.nih.gov/15345176/

Efficacy of low power laser therapy and exercise on pain and functions in chronic low back pain.This study shows Phototherapy seemed to be an effective method in reducing pain and functional disability in the therapy of chronic low back pain.

Link: https://pubmed.ncbi.nlm.nih.gov/12605431/