Red light devices

• Look for the wavelength in nanometres, the irradiance in mW/cm2 and the distance it was measured at.
• The review says inconsistent reporting of these is a major source of contradictory research findings.
• Output stated in watts does not reveal power density, it notes, and irradiance depends on factors such as spot size.

Source: Journal of Biomedical Optics (via PubMed Central)

• CE certification was not evidence for medical efficacy claims, the ASA found.
• CAP advice says claims to treat conditions with LED devices are likely to be seen as medicinal claims.
• Devices making such claims must be registered with the MHRA before sale, and marketers need robust clinical trial evidence, CAP says.

Source: ASA, ASA / CAP

• Follow the manufacturer's instructions.
• Ask a pharmacist or GP if unsure.

What does the ASA say about red light therapy advertising?

In a 2021 ruling the ASA found red light therapy ads made medical claims, and that CE certification was not evidence for them. CAP says medicinal claims need MHRA registration and robust clinical trial evidence.

Why are irradiance figures hard to compare?

A light-parameter review says inconsistent reporting is a major source of contradictory findings, and that irradiance depends on factors such as spot size. Look for the distance it was measured at.

• Review of light parameters and photobiomodulation efficacy - dive into complexity, Journal of Biomedical Optics (via PubMed Central)
• ASA Ruling on Red Light Therapy Ltd (A21-1094015), ASA
• Advertising guidance - Lasers and LED devices for acne, ASA / CAP