Red light therapy is not a cancer treatment, and nothing on this site should be read as suggesting it is. This page exists because people search for this topic, and the honest answer matters more here than anywhere else.
What the study actually was
A laboratory study published in 2020 exposed two types of breast cancer cells, grown in dishes, to LED red light at 660 nm. The researchers reported reduced cell growth and linked it to autophagy, a process in which cells break down their own components.
This was cell culture research. Cells in a dish behave very differently from a tumour in the body, and many results at this stage never translate to people. There are no human trials showing that red light therapy treats or slows breast cancer.
Why caution is the right default
Laboratory research on light and cell growth points in more than one direction. Because light can stimulate cell activity, many clinical guidelines advise against using light therapy over a known or suspected tumour.
Separately, specialised photobiomodulation protocols are used by some hospital teams to help manage side effects of cancer treatment, such as mouth sores during chemotherapy. That is a clinical procedure run by the care team, not something to replicate at home.
If you have or have had cancer
- Speak to your oncology team before using any light therapy device
- Do not use light therapy over a tumour or a suspected tumour
- Never delay or replace any part of your cancer treatment
Source
Laboratory study: PubMed 32654094.
