Skin cycling. The celebrities secret

There are some simple rules of beauty that are practically a given at this point — we all know how important it is to cleanse regularly, moisturize and always apply SPF. But when you start adding more products, like anti-aging serums or exfoliants, it gets a little more complicated. You may be asking: What time should I apply each one? And what's the best order to apply them in? With all these variables, we sometimes wish that there was just a simple beauty formula to follow.

Recently, we've seen a trend going around on TikTok that seems like it could be just that. Skin cycling is essentially a four-night skin care regimen that you repeatedly cycle through to simplify your routine and potentially reduce inflammation from active ingredients. Videos featuring the #skincycling tag have 90 million collective views on the app. One person said that it "transformed" their "sensitive acne prone skin" and another claimed that it made their skin "look the best it ever has."

So what exactly is it? 

Dr. Whitney Bowe, a New York-based dermatologist has been credited with coining the term "skin cycling." According to Bowe, the classic skin cycling routine consists of a four-night schedule. Night one is exfoliation, night two is for retinoids and nights three and four are recovery nights, where you focus on hydration and barrier repair. Once you finish the cycle, you repeat the process.

While the idea of "skin cycling" is currently trendy, it's not necessarily new. "Skin cycling is a well-known treatment protocol in dermatology," said Dr. Shari Lipner, associate professor of clinical dermatology at the Weill Cornell Medical Center in New York, to Shop TODAY.

Retinoids, in particular, have often been cycled as many people cannot tolerate them nightly, said Dr. Mary L. Stevenson, associate professor at the NYU Grossman School of Medicine. Plus, she said, people don't always have time to correctly apply products, so they have to cycle through them instead. For example, TODAY previously reported that you should wait an hour after applying exfoliating acids like AHAs and BHAs before putting retinol. But if you're doing your routine before bed (it's recommended that you apply both products at night), you don't always have the time to wait. So, by applying one product one night and the other the next, you're essentially cycling.

What are the benefits of skin cycling?

In another video, Bowe explained that this specific skin cycling routine not only helps you get more out of your ingredients (she said the exfoliation helps prep your skin for the retinoid) but it also helps you avoid irritation.

xfoliating and retinol-based products can be irritating to the skin, Lipner said. And that's why the recovery nights are important. "The recovery nights let the skin recover and rejuvenate," she said.

Lipner said that this cycling regimen could be beneficial for those who want to even out their skin tone or have acne.

Is skin cycling safe?

That being said, Lipner added that the four-day cycling routine is not ideal for all skin types. Exfoliation twice per week can be too irritating for some (she recommends a max of once per week), so she said that you should talk to your dermatologist, who can look at your skin and determine the right routine for you. And if you do find that the exfoliation is too irritating, you should skip that step.

Stevenson also said that while some skin types can only tolerate two nights of retinol per week (making this routine somewhat of a sweet spot for them), others can handle more.