Experts say walnut isn't exactly gentle on your skin.

By Julia Guerra
Kylie Jenner's YouTube video explaining Kylie Skin's walnut face scrub
Credit: Kylie Jenner/YouTube

As Kylie Jenner prepares to release Kylie Skin to the masses on May 22, the cosmetic mogul gave a sneak peek of her new skin-care line to fans via a series of introductory videos on her YouTube channel.

The videos feature Jenner talking about each product in the line, which includes a moisturizer, an eye cream, a foaming face wash, a vanilla milk toner, a vitamin C serum, and one more product that seems to have struck an especially sensitive chord with even the most loyal Jenner fans: a walnut face scrub. (Related: I Tried the Collagen Creamer Kylie Jenner Puts In Her Coffee Every Day for Glowing Skin)

In the short clip, Jenner describes her "secret to a fresh face" as "really gentle, gentle enough to use every day," noting that she personally only uses it two or three times a week.

"Some walnut face scrubs are kind of harsh on the skin. This isn't too abrasive. It really leaves my face feeling super baby soft," Jenner explained, adding that the scrub also "makes you look glowy, and takes away dead skin cells." (Related: 5 Science-Backed Ways to Glow from the Inside Out)

Soon enough, people on Twitter were up in arms.

In case you're totally lost, here's why people are freaking out: In 2017, skin-care brand St. Ives underwent a lawsuit for its use of crushed walnut powder as a key ingredient in its Apricot Scrub product. The plaintiffs claimed that the scrub both damages the skin and clogs the pores, according to an official press release from Top Class Actions.

Even though the lawsuit was tossed out in December 2018, crushed walnut powder has remained a relatively controversial skin-care ingredient. But is walnut actually bad for your skin?

"Walnut powder comes from crushed walnut shells, and neither of them is safe for the skin. Their jagged edges cause microtears on your skin, which damages your skin barrier and can lead to skin irritation, enlarged pores, and can even aggravate acne," Howard Sobel, M.D., a board-certified dermatologist and founder of Sobel Skin, tells Shape.

Apparently, it also doesn't really matter what form of walnut a skin-care product contains. If the size or consistency of the ingredient is large or jagged enough, it can lead to microtears, abrasions, and other skin injuries, adds Deanne Robinson, M.D., a board-certified dermatologist with Modern Dermatology in Connecticut. (Related: 10 Facial Exfoliators That Will Completely Transform Your Skin)

As for Kylie Jenner's walnut scrub being fit for daily use, that's also going to be a hard no. "For someone with healthy skin, they can exfoliate their face using a gentle AHA or BHA cleanser or toner daily," Dr. Sobel says. (Keyword: Gentle.) "For more intense exfoliation, use an exfoliating peel or mask with a slightly higher concentration of fruit acids and enzymes one to two times a week." (Related: PHA Acids Might Be the Best Exfoliating Ingredient for Sensitive Skin)

If you still want to use a physical exfoliator rather than a chemical one, a gentler alternative to walnut shells is jojoba beads. They're a commonly-used exfoliant in scrubs and masks that will buff off dead skin cells while hydrating the skin, without the negative environmental impact of synthetic microbeads.

Considering Kylie Skin hasn't even launched yet and it's already getting this much buzz, we can only imagine the stir it'll cause when the full skin-care line's ingredients lists are revealed.