WEN by Chaz Dean is in the middle of a large class action lawsuit involving their “Cleansing Conditioner” products that lead to severe hair loss.

Last Dec., more than 200 people, from 40 different states, filed a class action lawsuit against WEN and Guthy-Renker, its parent company. The lawsuit claims that WEN’s cleansing conditioner has resulted in extreme hair loss, as well as, rashes, hair breakage, and scalp irritation. The lawsuit also states that WEN and Guthy-Renker knew of the complaints involving this product and they refused to take action.

The United States Food and Drug Administration (FDA) joined the investigation in July after receiving 127 direct reports involving damaging results from WEN’s cleansing conditioner. Once the FDA started their investigation, they found that more than 21,000 complaints were directly submitted to Guthy-Renker, LLC and Chaz Dean, Inc.

Following the filing of the class action lawsuit, WEN, Chaz Dean, and Guthy-Renker denied the allegations in a statement to NBC News.

“There is no scientific evidence to support any claim that our hair care products caused anyone to lose their hair. There are many reasons why individuals may lose their hair, all unrelated to WEN hair products.”

The suit claims that the products contain “one or more active ingredients that act as a depilatory or caustic agent, causing a chemical reaction that damages the hair strand and/or follicle.” Health magazine enlisted the help of dermatologist Mary Gail Mercurio, MD to confirm the claims made. She did not find an ingredient that supported the claim. She also said that women can lose their hair for a variety of reasons and it seems unrelated to usage of WEN’s cleansing conditioner.

Hair colorist Andrea DiCostanzo, of Totally Hott Salon in Rye Brook, New York, has recommended WEN to clients in the past and has not received any negative feedback. DiCostanzo does not see the connection between WEN’s cleansing conditioner and hair loss.

“Everyone is different so some people may react to the product because of skin issues or allergies,” DiCostanzo said.

DiCostanzo thinks WEN will have to remove the cleansing conditioner because of the lawsuit and the overwhelming number of complaints.

“Normally, over time, if there is something that has realized to be harmful in any product, the company is forced to take it off the market,” DiCostanzo said.

The FDA has requested WEN to “provide any data that might help us to better understand the reports of hair loss associated with the use of WEN by Chaz Dean Cleansing Conditioner products.” The investigation is ongoing.