If your TikTok feed is full of glowing, sci-fi-esque LED masks, you’re not alone. Red and blue light therapy devices have officially become the newest beauty shelfies, with creators flooding TikTok and Instagram with snapshots of themselves lit up in neon hues. “In the last few years, there has been a massive number of light-based therapies hitting the market,” says dermatologist Maryam Safaee, MD.

But with so many beauty gadgets promising clearer, firmer, glowier skin, figuring out what actually works can feel overwhelming. The good news: Experts say both red and blue light therapy can genuinely benefit your skin. The bigger question is which one is right for your specific concerns. Ahead, dermatologists break down the differences between red light vs. blue light therapy, including the benefits, drawbacks, and who should use each one.

“Red light therapy, also called photobiomodulation, is a non-invasive treatment that uses red or near-infrared light to effect changes at the cellular and mitochondrial level to improve the appearance and firmness of the skin,” says dermatologist Morayo Adisa, MD. “In addition, light therapy skincare treatments that use different wavelengths in the visible light and near infrared spectrum can also help with the reduction of inflammation, treatment of acne and breakouts, accelerate wound healing, and stimulate hair growth in addition to improving fine lines and wrinkles.”

Dr. Safaee explains that red light therapy uses red light in the 620-700 nm wavelength and near infrared 700-1440 nm spectrum. “Without getting too lost in the science, the light emits photos in the skin which are absorbed by specific photoreceptors and lead to several downstream effects beneficial for the skin,” she says, adding that red light therapy is safe for almost all skin types and skin colors. Unlike certain lasers, which may not be suitable for those with darker skin, red light does not target melanin, so it’s safe to use in all skin colors.

“Blue light has antibacterial and anti-inflammatory properties, so it helps to kill Cutibacterium acnes, the bacteria that contribute to acne, while also decreasing inflammation,” Dr. Adisa says.

Blue light uses a wavelength in the 400-500 nm range. It can penetrate the skin up to a depth of 1 mm, whereas red light can penetrate much deeper, explains Dr. Safaee. “It’s very important to mention that, unlike red light, blue light can cause hyperpigmentation to those with darker skin types, so I generally recommend it for those with lighter skin types,” she says.

“I like to think of red and blue light therapy working synergistically together and not interchangeably,” Dr. Safaee says. “They are both LED-based photomodulators but use different wavelengths. However, they have similar downstream effects in the skin. They create what we call controlled stress in the cell, which in turn leads to healing and repair, and both are anti-inflammatory.”

In addition to the difference in wavelength, red light can penetrate up to 6 mm into the skin, whereas blue light only penetrates up to 1 mm. “That is why red light is more effective for treating wrinkles and textural changes, as you need a deeper penetration to induce the changes necessary for anti-aging,” Dr. Safaee says. “For conditions like acne, I recommend using both a blue and red light mask; they will work synergistically. The blue light will exert the anti-bacterial effects, and the red light, which goes deeper, will help with the tissue repair.”

“The frequency of use is determined by the specific device you have,” Dr. Adisa says. For red light therapy, Dr. Safaee typically recommends two to three sessions a week at 20-minute intervals. “Studies have shown with this regimen, you can see improvements of 26-36 percent in overall wrinkle reduction in as little as six weeks, although I suggest at least several months of therapy to fully assess the benefit,” she says.

For blue light therapy, Dr. Safaee suggests using it every other day for at least 8 weeks, at which point you should start noticing a reduction in the acne lesions.

“First, discuss this with a board-certified dermatologist before using red or blue light at home,” Dr. Adisa says. “Red light therapy is not for everyone, and a board-certified dermatologist can help ensure the appropriateness of the treatment for you. Choose a red-light device that is created for what you want to treat and has been FDA cleared. An FDA-cleared device will have it stated on the packaging. Although these devices are generally considered safe, care must be taken with the use of these devices to prevent side effects such as redness, exfoliation, burning, pain, headaches, blistering, discoloration, and potential retinal damage.”

Make sure you have the correct wavelength. For red light therapy, you want a device that has both red light and near infrared, because the near infrared allows for deeper penetration into the skin, and that is the key to the anti-aging benefits.

“You must find one that has several key safety features; you are wasting your money and just paying for a fancy lamp,” Dr. Safaee says. “FDA clearance means the device was cleared for the specific condition it was intended to treat, for example, acne or pigmentation, or wrinkle reduction. Many companies will ignore this step and label their product as cosmetic, thus there is no validation that their device is actually working in the manner they are suggesting.”

That depends. “If you are treating mild forms of acne or looking to reduce fine lines, you can certainly see some benefit with at-home devices,” Dr. Safaee says. “However, for more severe acne or those with deep-set wrinkles, your money is better spent seeing a board-certified dermatologist.”

Between the two forms of light-based therapy, red light is considered safer, according to Dr. Safaee. “It can be used on all skin colors; however, blue light should be cautioned against use in darker skin types due to concerns for hyperpigmentation,” she says.

Additionally, in some cases, Dr. Adisa cautions that light therapy can cause skin irritation, worsening of melasma or hyperpigmentation, and photosensitivity. Always be sure to follow the manufacturer's recommended directions to ensure proper use.

• Maryam Safaee, M.D., is a board-certified dermatologist in Los Angeles.
• Morayo Adisa, M.D., F.A.A.D., is a double board-certified dermatologist and Medical Director Dermatology Physicians Chicago/ Kenilworth.

Celia Shatzman (she/her) is a Brooklyn-based journalist who has covered beauty for two decades and loves an at-home skincare device.