One of the most popular facial scrubs has been hit with a lawsuit that claims the product can do real harm to your skin. TMZ reports that St. Ives Apricot Scrub is at the center of a suit that claims a key ingredient — walnut shells — can cause skin damage.

According to Top Class Actions, plaintiffs Kaylee Browning and Sarah Basile have sued Unilever, the parent company of St. Ives, and the suit may become class-action. The lawsuit centers around the inclusion of crushed walnut shells in its scrubs; the plaintiffs claim the ingredient makes the exfoliator completely unsuitable to use on your face. The plaintiffs, who claim false advertising, say they both bought the products based on the marketing, but never would have purchased them if they had known it could cause skin damage.

A New York magazine article cited in the lawsuit consulted dermatologists, who argued that “large, hard, and sandlike rocks” like in the St. Ives scrub are the most harmful to the skin on your face, and could even lead to breakouts or wrinkles. This isn’t the only time the scrub has been criticized, too; Racked notes that as early as 2001, online reviewers called it “damaging” and even painful to use.

The lawsuit, which seeks $5 million in damages, takes issue with the product’s “dermatologist tested” label, claiming that St. Ives still doesn’t disclose that the product isn’t recommended by dermatologists. Also included in the suit is the scrub’s claim to be non-comedogenic, or not pore-clogging; the suit claims that the scrub contains ingredients that do clog pores. The American Academy of Dermatology warns against scrubbing your skin or using harsh products; the group urges people to contact their dermatologist to figure out the best way to exfoliate for their skin types.

On St. Ives’ website, the company lists walnut shells as “one of the natural exfoliants we use to keep skin soft and glowing,” and notes that the walnuts they use are “milled into a fine powder so they have specifically rounded edges, which means a softer scrub.”

A Unilever spokesperson issued the following statement in response:

As a general practice we do not comment on pending litigation. We can say that for over 30 years, consumers have loved and trusted the St. Ives brand to refresh and revitalize their skin. We are proud to be America’s top facial scrub brand and stand by our dermatologist tested formula.

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