Most shampoos don’t list “formaldehyde” on the label, but many contain preservatives that slowly release it. These chemicals, called formaldehyde releasers, are added to prevent bacterial growth in water-based products. The most common one in shampoos is DMDM hydantoin, followed by imidazolidinyl urea, diazolidinyl urea, and quaternium-15. If any of these appear on your shampoo’s ingredient list, the product contains formaldehyde.
Brands That Have Used Formaldehyde Releasers
According to the Environmental Working Group’s cosmetic database, shampoos containing DMDM hydantoin have included products from well-known brands: Garnier Fructis, Dove, Alberto VO5, AXE, Hempz, Joico, and several salon lines like Zotos Professional Biotera. These aren’t obscure or discount brands. They’re products you’d find in any drugstore aisle.
Formulations change over time, so a product that contained DMDM hydantoin two years ago may have been reformulated since. Several class-action lawsuits filed against Johnson & Johnson and Unilever claimed that DMDM hydantoin in their shampoos caused hair loss, which pushed some manufacturers to quietly swap out the ingredient. The only reliable way to know what’s in your current bottle is to check the ingredient list yourself.
Names to Look for on the Label
Formaldehyde releasers go by many names, and manufacturers aren’t required to flag them as formaldehyde-related on U.S. labels. Here are the main ones to watch for:
- DMDM hydantoin (also listed as 1,3-dimethylol-5,5-dimethylhydantoin)
- Imidazolidinyl urea (sometimes sold under trade names Germall 115 or Euxyl K 200)
- Diazolidinyl urea
- Quaternium-15 (also labeled as Dowicil 75, Dowicil 200, or chloroallyl hexaminium chloride)
- Bronopol (2-bromo-2-nitropropane-1,3-diol)
If you see any of these in the ingredient panel, the product releases free formaldehyde during normal use and storage. DMDM hydantoin releases more formaldehyde at higher temperatures and at neutral or alkaline pH levels, which means a bottle sitting in a warm bathroom or shower may contain more free formaldehyde than one stored in a cool cabinet.
How Much Formaldehyde Is in Shampoo
Both U.S. and EU regulations allow free formaldehyde in cosmetics up to 0.2% (2,000 parts per million). That may sound like a small amount, but formaldehyde is potent at low concentrations. The International Agency for Research on Cancer classifies formaldehyde as a Group 1 carcinogen, meaning there is sufficient evidence it causes cancer in humans, specifically nasopharyngeal cancer, with strong links to leukemia as well.
The exposure from a single shampoo wash is brief, and the cancer risk data comes primarily from people with heavy occupational exposure, like embalmers and factory workers. But for people who are already sensitized to formaldehyde, even trace amounts matter. Patch testing shows that fewer than 5% of people with eczema test positive for formaldehyde allergy, but when the allergy is present, it’s almost always clinically significant, causing itching, redness, and flaking on the scalp or wherever the product touches skin.
EU Labeling Is Changing, U.S. Rules Lag Behind
The European Union banned adding formaldehyde directly to cosmetics but still permits formaldehyde-releasing preservatives. Starting in 2024, however, any EU cosmetic product releasing more than 0.001% (10 parts per million) of formaldehyde must carry a label warning that reads “releases formaldehyde.” That threshold is 50 times lower than the previous one of 0.05%, a change driven by scientific advisors who concluded the old limit didn’t protect people with formaldehyde sensitivity. Brands have until July 2026 to sell through older stock.
The U.S. has no equivalent labeling requirement. The FDA does not require manufacturers to disclose that a preservative releases formaldehyde, and the word “formaldehyde” won’t appear anywhere on a bottle of shampoo containing DMDM hydantoin. You have to recognize the chemical names yourself.
How to Choose a Formaldehyde-Free Shampoo
The simplest approach is to scan the ingredient list for the five preservative names listed above and skip anything that contains them. Many brands now market themselves as “formaldehyde-free,” though this isn’t a regulated claim in the U.S., so verifying the ingredient list is still worth your time.
Brands that use alternative preservation systems tend to rely on ingredients like phenoxyethanol, sodium benzoate, or potassium sorbate instead of formaldehyde releasers. Lines from companies like Ceremonia, Ethique, Prose, SEEN, and Plaine Products are examples of brands that avoid both formaldehyde releasers and parabens, using plant-based surfactants from coconut oil alongside simpler preservation methods. Keep in mind that “natural” on a label doesn’t guarantee a product is free of formaldehyde releasers. One study found that formaldehyde can appear at contaminant levels even in products marketed as clean or natural.
The EWG’s Skin Deep database lets you search any specific product and see whether it contains a formaldehyde releaser, which can be useful if you want to check a product before buying it. Searching for the preservative name plus “shampoo” will return a list of flagged products.