Alternating blue and red light for acne

How the study worked

Twenty-four people had eight treatments, twice a week. Sessions alternated 415 nm blue and 633 nm red light and lasted 20 minutes. Each was preceded by mild microdermabrasion, a form of exfoliation.

Researchers counted spots at the start and at weeks 2, 4, 8 and 12.

The results

Twenty-two people completed the study. Spot counts fell by 46% at four weeks and 81% at twelve weeks. Inflamed spots improved more than blackheads and whiteheads. Severe acne improved slightly more than mild acne. Side effects were mild and brief.

What is still unclear

There was no comparison group. Exfoliation before every session may have contributed to the result.

What to take from this

Spots improved, but the study cannot separate the effects of light and exfoliation.

Devices that list similar light

Three of the 5 masks in the comparison list a wavelength in every band used here (blue near 415 nm and red near 633 nm). They are examples, listed alphabetically, each with our specification page and the manufacturer’s own product page. Related devices are examples, not evidence that a study tested that retail model.

• CurrentBody Skin LED Face Mask Series 3415 · 532 · 590 · 633 · 830 · 1072 nm · CurrentBody product page
• Dr. Dennis Gross DRx SpectraLite FaceWare Pro415 · 630; page also lists 605 · 880 (unresolved) nm · Dr. Dennis Gross product page
• Shark CryoGlow FW312415 · 630 · 830 nm · Shark product page

These masks list one of the bands, but not all:

• Dr. Renú SpectraLift Advanced465 · 530 · 630–660 · 850 nm · Dr. Renú product page
• Omnilux Contour Face633 · 830 nm · Omnilux product page

Matching a wavelength is not the same as matching the study. Dose, irradiance, session length and schedule also differ, and a mask’s reported output is not independently measured. See how dose works and home vs clinic doses.