TikTokers are using blue light to cure acne. Dermatologists say it's actually a good idea.

Is light therapy the future of skincare? Plenty of TikTokers seem to think so − and dermatologists aren't mad about it.

In addition to red light therapy, which has made rounds on the video-sharing app for its supposed anti-aging benefits, blue light is also having a moment, with users touting it for acne prevention.

Turns out, the TikTokers are actually onto something. Dermatologists say there's evidence blue light − at a wavelength of around 400 nanometers − can kill a particular bacteria known to cause acne. They also say blue light therapy can pair well with its red light counterpart, which has been shown to regulate the skin's oil production and boost collagen.

What about red light therapy?Dermatologists weigh in

"It's one of the non-invasive, less aggressive, more natural approaches that may help someone achieve improvement in acne and rejuvenation," Dr. Danilo Del Campo, a Chicago-based dermatologist, says. "It's a good starting point, but it often is not the ending point, so I think it's a good approach with minimal risk."

What is blue light therapy and how does it work?

According to dermatologists, blue light's main benefit is acne prevention. That's because blue light is an effective weapon against bacteria porphyrins, which are sensitive to light.

By activating bacteria porphyrins, blue light can oxidize and, therefore, destroy bacteria on the skin, helping treat inflammatory lesions of acne, says Dr. Anthony Rossi, a New York-based dermatologist.

"What we're realizing now is that both blue light and red light have good beneficial effects," he says. "Whereas red light's more anti-inflammatory, blue light can be more anti-bacterial or anti-microbial. If you have a very inflammatory acne, then blue light's really helpful to calm down that inflammation and that bacteria."

Acne prevention isn't all blue light is good for either. It also has potential antioxidant benefits, can aid skin-cell turnover and may even destroy cancer and pre-cancer cells when used in conjunction with certain medications, Del Campo says. The treatment in which blue light is used to activate cancer-fighting creams on the skin is called photodynamic therapy, or PDT.

Blue light therapy is not for everyone

Though blue and red light therapies are generally safe, there are some risks dermatologists want to highlight.

The first is that not all over-the-counter light therapy products are created equal. If you're interested in light therapy, consult a board-certified dermatologist first for their recommendations. Additionally, many dermatologists also offer light therapy at their offices, which is often safer and more effective than at-home devices.

Additionally, what's good for the skin isn't necessarily good for the eyes, especially blue light, which may disrupt people's circadian rhythms when exposed to their eyes. It's important to wear proper eye protection or to keep eyes closed when receiving any kind of light therapy or treatment.

"You really don't want to keep your eyes open. You don't want to stare into these lights," Rossi says. "You don't want your cornea constantly exposed to all this blue and red light."

Blue light may also exacerbate certain skin conditions like hyperpigmentation and melasma, so people with those probably should avoid the treatment as well, Dr. Rossi says.

"Outside of that, it's really well-tolerated," Dr. Del Campo says.

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