The Shampoo Lawsuits: What Is Actually Happening

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Beauty and Cosmetics Law Africa (BCLA) | The Shampoo Litigation Series — Part I of II

Introduction

Most people who have followed coverage of the global hair relaxer litigation, including BCLA's own series on MDL No. 3060, are aware that it has brought considerable attention to the use of formaldehyde-releasing chemicals in beauty products. A separate group of ongoing lawsuits concerns another everyday beauty product: shampoo.

The shampoo cases are not as large or as consolidated as the hair relaxer litigation. There is no single multidistrict litigation bringing the cases together, and the scientific evidence concerning some of the allegations remains contested. The cases nevertheless involve major beauty companies and products used by millions of consumers.

One of the ingredients that appears repeatedly in these cases is DMDM hydantoin, a preservative used in a range of personal care products, including shampoos and conditioners. The ingredient has attracted attention because it can release small amounts of formaldehyde as it breaks down.

For African markets, the issue is worth following closely. Some of the brands involved in the litigation are sold across the continent, while the regulatory treatment of cosmetic ingredients can differ between jurisdictions.

This article sets out what the current litigation is about, the cases that have attracted the most attention, and what has and has not been established so far. Part II will consider the broader questions these cases raise about ingredient safety, regulatory oversight and accountability in the beauty industry.

DMDM Hydantoin: The Ingredient at the Centre of the Cases

DMDM hydantoin is a preservative used in water-based personal care products, including shampoos, conditioners, body washes and moisturisers. Its purpose is to prevent the growth of bacteria, fungi and yeast that could otherwise contaminate a product. It is a formaldehyde-releasing preservative. Through a process known as hydrolysis, DMDM hydantoin releases small amounts of formaldehyde over time.

Formaldehyde itself is a recognised human carcinogen. The U.S. National Toxicology Program classifies it as such, and exposure to formaldehyde is subject to regulatory controls in a number of jurisdictions.

The presence of DMDM hydantoin in a cosmetic product, however, does not by itself establish that the product is unsafe. The industry's position has been that DMDM hydantoin can be used safely at the concentrations permitted in cosmetics. The Cosmetic Ingredient Review expert panel and the European Union's Scientific Committee on Consumer Safety have also considered the ingredient acceptable under specified conditions of use.

The companies involved in the litigation have similarly maintained that the amount of formaldehyde released by DMDM hydantoin during normal product use is not sufficient to cause the injuries alleged by plaintiffs. The legal claims, however, go beyond that scientific question.

Plaintiffs in various cases have alleged that manufacturers failed to warn consumers adequately about the ingredient, made misleading representations about product safety, or could have used alternative preservatives. Some claims also allege that DMDM hydantoin-containing products caused hair loss, scalp irritation or other adverse effects. It is worthy to note that these are allegations, not findings of fact. Generally, whether the products caused the injuries claimed, and whether manufacturers breached any legal duty, must be determined on a case-by-case basis.

The Main Cases

The litigation can broadly be divided into several groups.

1. TRESemmé — Unilever: TRESemmé was among the first major shampoo brands to face a significant number of lawsuits concerning DMDM hydantoin. Several class actions were filed in U.S. federal courts, including in New Jersey and Illinois. Plaintiffs alleged that certain TRESemmé products containing DMDM hydantoin caused hair loss, scalp burns and irritation, and that Unilever failed to adequately disclose the risks associated with the ingredient. Unilever maintained that its products were safe. The company nevertheless announced in 2021 that it would reformulate TRESemmé products to remove formaldehyde-releasing preservatives. By July 2022, TRESemmé products sold in the United States no longer contained DMDM hydantoin. The change did not amount to a recall. As a result, products manufactured before the reformulation could continue to be sold or remain in consumers' homes. The litigation has had mixed results. In July 2025, a federal judge in New York denied class certification in one of the cases, citing issues including individual questions of causation and differences among applicable state laws. A separate case was dismissed in July 2026 on statute of limitations grounds. Some claims have resulted in settlements, while others have continued. There has not been a landmark trial verdict establishing that DMDM hydantoin in TRESemmé products causes hair loss.

2. OGX — Johnson & Johnson: OGX is another major brand involved in litigation concerning DMDM hydantoin. The principal case, Carr v. Johnson & Johnson Consumer Inc., Case No. 1:21-cv-06557 in the Eastern District of New York, includes allegations relating to design defect, failure to warn and negligence in connection with OGX products containing DMDM hydantoin. As of July 2026, the matter remains pending before U.S. District Judge Eric Komitee, with no trial date set. Unlike the hair relaxer litigation, the OGX cases have not been consolidated into a nationwide MDL. Various class and individual claims have proceeded separately, with some claims resolving through settlements.

The absence of a single consolidated proceeding makes the overall litigation more difficult to assess. Different courts may consider different evidence, claims and procedural issues.

3. Dry Shampoo — Batiste, IGK and Others: A separate group of cases concerns dry shampoo products and a different ingredient: benzene. Independent testing identified benzene in certain dry shampoo products, including products associated with brands such as Batiste and IGK. Benzene is a recognised carcinogen and has been associated with certain forms of cancer, including leukaemia. These cases are distinct from the DMDM hydantoin litigation. They concern alleged contamination rather than the use of a formaldehyde-releasing preservative. Several cases have resulted in settlements. The litigation has also highlighted an important issue in product liability claims: plaintiffs generally need to establish a connection between the product they purchased or used and the alleged contamination. Evidence that a particular brand had contaminated batches does not necessarily establish that every product sold under that brand was contaminated. The settlements reached in these cases therefore should not be treated as findings that the products caused cancer.

4. Suave — Unilever: A fourth group of claims concerns Suave products. Unilever previously recalled certain Suave aerosol products following concerns about benzene contamination and subsequently settled related litigation. Complaints in the TRESemmé litigation have referred to the Suave recall in arguing that Unilever had knowledge of concerns relating to certain ingredients while continuing to sell other products containing DMDM hydantoin. That allegation forms part of the broader failure-to-warn arguments made by plaintiffs. It remains an issue for the relevant courts to determine.

How the Shampoo Litigation Differs from the Hair Relaxer Cases

There are two major differences.

The scientific evidence is different

The hair relaxer litigation has received significant attention following the publication of findings from the NIH Sister Study. That longitudinal study followed more than 33,000 women for almost 11 years and reported an association between frequent use of chemical hair straighteners and an increased risk of uterine cancer.

The evidence concerning DMDM hydantoin and hair loss is different.

There is established evidence concerning the hazards associated with formaldehyde exposure, as well as evidence that formaldehyde-releasing preservatives can cause allergic or irritant reactions in some circumstances. That does not, however, establish that DMDM hydantoin in shampoo causes hair loss.

The cases are fragmented

MDL No. 3060 brings thousands of hair relaxer claims together before a single federal judge. The coordinated proceeding allows the parties to conduct common discovery, address recurring legal issues and prepare selected cases for bellwether trials. The shampoo litigation does not have that structure. Instead, claims involving different products and different allegations have proceeded in separate courts and at different stages. Some have been dismissed. Some have settled. Others remain pending.

Why This Matters for African Markets

The legal proceedings are taking place in the United States, but the products involved are not confined to the U.S. market. TRESemmé is distributed across African markets, while OGX and other international haircare brands are also increasingly available to African consumers. This raises a practical regulatory question: are the products sold in African markets the same formulations that are sold in the United States?

Cosmetic formulations may change over time and may differ between markets because of regulatory requirements, manufacturing arrangements, product availability or commercial decisions. A reformulation announced for products sold in the United States therefore does not, by itself, establish that products sold elsewhere contain the same ingredients.

This is a reminder of the importance of regulatory systems that can respond to developments outside their own jurisdictions. Scientific evidence and product safety concerns do not stop at national borders, even though regulatory authority does.

What the Litigation Tells Us So Far

The shampoo litigation is still developing. It has not produced a definitive judicial finding that DMDM hydantoin causes hair loss, nor has it established that every product containing the ingredient presents the same risk. What the cases do demonstrate is the growing legal importance of cosmetic ingredients.

Preservatives, fragrances and other formulation ingredients are no longer matters that consumers, manufacturers and regulators can treat as purely technical questions. They can become central to product liability claims, consumer protection disputes and regulatory scrutiny.

The next question is therefore broader than whether DMDM hydantoin is safe. It is how the global beauty industry responds when questions about an ingredient move from scientific and regulatory discussions into litigation, and whether regulatory systems in other markets are equipped to respond. Part II of BCLA's Shampoo Litigation Series will examine that broader question.

This article is Part I of BCLA's Shampoo Litigation Series. It is intended for informational and educational purposes and does not constitute legal advice. All information is current as of the date of publication.