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Beautiful young woman with hairdresser washing head at hair salon

Associate Attorney
Grewal Law, PLLC
(855) 610-0503

Two class action lawsuits have been filed against Unilever, the manufacturer of TRESemme hair care products for failing to warn its consumers about a dangerous chemical found in the products. The ingredient is a formaldehyde-releasing preservative called DMDM hydantoin and it has been found in some Unilever manufactured shampoos, including TRESemme Keratin Hair Smoothing Shampoo and TRESemme Keratin Smooth Color Shampoo.


DMDM hydantoin is described as “a formaldehyde donor known to slowly leach formaldehyde when coming into contact with water” and is “a well-known human carcinogen.” The lawsuit claims that the ingredient, on its own or in combination with other ingredients commonly found in shampoos, causes significant hair loss and scalp irritation when applied properly. These complaints are noticeably similar to those made by users of Suave Professionals Keratin Infusion in 2012, one of TRESemme’s leading competitors.

The complaints allege that Unilever has known of the harmful effects of DMDM hydantoin as a carcinogen since at least 2012. However, Unilever “continued to proudly include this ingredient as a preservative in its products,” and, in fact, continued to claim that its products were safe for use when properly applied. The class actions were filed in the U.S District Courts for the Northern District of California and Northern District of Illinois on November 16, 2020.


  1. Gravatar for BETH POSEY

    I have been using tre semme shampoo for years and lately I switched to the color one with keratin and more moisture. My hair comes out in globs. I thought it was my age till someone saw it in my bathroom and told me about it

    1. Cheyenne Benyi

      Yes- I'm glad you found this article! I'll be keeping an eye on the ingredient lists for any shampoo I buy in the future. I found DMDM Hydantoin in the Tresemme anti-breakage shampoo I had in my shower!

      1. Gravatar for Amber

        I'm nearly bald, my hair is so brittle and thin. I started using Treseme 5 years ago and my hair is Destroyed!!

        My hair was beautiful and long and thick... now I'm so ugly

    2. Gravatar for Melinda

      Same I thought it was age... I’ve been using it for years on my kids too! Salon quality? 😡

  2. Gravatar for Amanda

    I've been using this shampoo for almost a year and I've been noticing that my hair was fall out and I didnt understand what was going on .until my daughter told me about the shampoo and conditioner. Know it all makes sense my hair was so full and now I cant even put my hair in a pony tail it do then and my daughter hair is thin also and her hair is thicker then mine. When we get out of the shower there is so much hair in the drain.

    1. Cheyenne Benyi

      Oh no! I'm sorry to hear about that Amanda.. I'm glad to know your daughter was able to key you in!

  3. Gravatar for Annette Plante
    Annette Plante

    I’ve noticed bumps in my hair line and my scalp

  4. Gravatar for Jessica Scott
    Jessica Scott

    I used Tresseme Keratin Smooth Shampoo

  5. Gravatar for Jessica Scott
    Jessica Scott

    I after I had started using TRESemme Keratin Smooth Shampoo, I started experiencing severely damaged and scalp burns and irritation. The burns were so severe that I made multiple visits to the ER. During those visits I received several diagnoses of psoriasis, of alopecia, one dr even speculated that it might have been a fungus. I was given prescriptions for steroids, I shaved my head, I invested in hats and wigs to wear in public. This went on for almost a year. Finally I ended up taking a trip to visit a family member and forgot my shampoo. During the 2 weeks that I was there, my hair and scalp started improving, better than it did with any of the prescriptions. I haven’t used TRESemme since.

    1. Gravatar for Amy

      Can we get our money back on this? I have 5 large bottles of Tresemme shampoo (Deep Cleanse and Healthy Volume) with the same ingredient.

  6. Gravatar for Barb

    I thought my hair was also due to age.

    Been using only this product for yrs.

    Seem to get worse last few years.

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