More than 200 women have joined a class-action lawsuit against the popular WEN all-natural hair products, claiming the sulfate-free shampoo and conditioners made their hair fall out.

Created by celebrity stylist Chaz Dean, WEN hair products are boosted as a natural alternative to regular shampoos. The products clean hair without using damaging sulfates, a chemical compound used to separate dirt and oil from hair or skin, and according to the product’s website, “It takes the place of your shampoo, conditioner, deep conditioner.”

Unfortunately, according to a large number of women from multiple U.S. states, the only results they saw from using WEN products was severe hair loss. BuzzFeed News reported that one user noticed hair loss after just one wash. In addition to hair loss, many women claim that WEN products have caused multiple injuries to their head and scalp, such as rashes, scalp irritation, hair breakage, and hair discoloration. One angry customer claimed that she had to quit her job as a professional model after she started using WEN products. “After using this product my scalp and face broke out in boils and my hair fell out in chunks.This shampoo destroyed my life,” she wrote on a product review, as reported by The Daily Beast.

According to the court papers, the company was aware of the unpleasant side effect and still failed to warn users. And although it’s true that many WEN users are happy with their results and praise the products, simply perusing Amazon reviews will show that many users also complained that the hair products caused them to lose large amounts of hair dating back many years. According to Kelsey Smart, a stylist at Fox & Jane salon in New York, the reason for the mixed reviews may have to do with WEN’s effect on different hair types.

“WEN seems to be good for certain hair types, especially those that are coarse or frizzy,” Smart, told The Daily Beast. “But for women with fine hair, it becomes more important for the scalp to stay really clean — otherwise, product can build up and lead to breakage.”

In response to the claims and the lawsuit, Joe Hixson, a spokesperson for WEN told BuzzFeed News that the complaints only represent a small fraction of its customers. “[We] intend to vigorously contest the allegations made against our products,” he said.

Unfortunately, baldness in women is a complicated health issue, which means it could be difficult to prove in court that WEN definitely led to these women’s hair loss. WebMD claims that everything from genetics to certain medications can lead to female hair loss. Nonetheless, a lawyer for the plaintiff told The Daily Beast that at the moment, the parties are attempting to settle their differences outside of court.