The claims about light-emitting diode (LED) skin devices certainly sound appealing. They treat everything from wrinkles, redness, and signs of aging to acne, scarring, and dark spots.

LED lights have been around since the 1960s, but have only recently been used as a skin treatment. Different wavelengths of the visible light spectrum correspond to different colors of LED light and penetrate the skin to different depths.

Depending on how deeply they penetrate, LED lights are thought to have different biological effects.
For instance, red and blue lights are typically promoted in LED skin treatments. Experts believe that red LED light acts on cells in the skin known as fibroblasts, which play a role in production of collagen, a protein that makes up a large part of connective tissue and helps the skin to recover when it's harmed.

So, in theory, red light could help to reverse some of the signs related to photoaging in the skin.

Blue LED light is most often used to treat acne. It does this by reducing activity in the sebaceous glands, so they produce less of the oil that can plug the hair follicles, leading to acne.

Blue light may also kill acne-causing bacteria known as Cutibacterium acnes. Often blue and red light are used in combination to help fight acne — the blue light targeting the C. acnes and the red light targeting inflammation and redness.

Pro tip: Home devices are typically less effective than professional treatments and you should not use LED therapy if you’re taking certain medications, such as isotretinoin (Accutane), for acne or use topical treatments that cause sensitivity to sunlight!