Updated February 16, 2023 at 12:38 PM ET

Nearly 30 women are suing hair care brand Olaplex for negligence and false advertising, claiming their products contain allergens and irritants that caused them hair loss and dry, brittle hair.

According to the lawsuit, Olaplex states in its marketing materials that their products, which include shampoos, conditioners and oils and are numbered 0 through 9, "restore damaged and compromised hair," while creating "healthy, beautiful, shiny, touchable hair," and that results are "proven by science." Those claims are false, states the lawsuit, which was filed last week in the U.S. District Court Central District of California.

According to the complaint, multiple Olaplex products contained lilial, a chemical compound that is often used as a perfume in cosmetics until the European Union mandated the ingredient be gone from products by March 2022 due to concerns about its impact on fertility.

Several of the products have won beauty awards and are sold on the Olaplex website, as well as in Sephora and Ulta from $30 to $96.

Plaintiffs allege Sephora removed lilial from the Olaplex ingredient list in June 2021, but Olaplex did not actually remove the chemical until February 2022 and still continues to sell its runoff inventory containing lilial instead of recalling them.

Olaplex was not immediately available for comment.

Additionally, the products contain panthenol, a form of vitamin B5 that can cause an allergic reaction, which resulted in cases of contact dermatitis for some women, and sodium benzoate and ascorbic acid, which together form benzene, a carcinogen, the lawsuit alleges.

The products also have non water-soluble ingredients, which cause the hair follicle to clog, resulting in seborrheic dermatitis and subsequently inflammation and hair loss, the complaint says.

"Defendants have been dismissive of their customers' hair loss, instead describing hair shedding as normal and unavoidable and attributing the hair loss to a long list of other potential causes," the complaint says.

Attorneys for the plaintiffs said they carefully considered any other causes of hair and scalp problems, but found that "the products alone are to blame."

The plaintiffs also accuse Olaplex of using celebrities and influencers to market their products, but failing to disclose that they have been paid, and that the company claims their products have been tested, but has not publicized those tests, which is "highly suspect," the complaint says.

Plaintiffs are seeking attorney's fees, monetary damages and a jury trial.

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