What are Formaldehyde Releasers?
Formaldehyde releasers are preservatives that slowly release small amounts of formaldehyde gas to prevent microbial growth in cosmetics. While "formaldehyde" is rarely listed directly on labels, these ingredients continuously release it at low levels over the product's lifetime. Common formaldehyde releasers include DMDM Hydantoin, Imidazolidinyl Urea, Diazolidinyl Urea, Quaternium-15, and Bronopol.
DMDM Hydantoin is so controversial that it's the subject of multiple class-action lawsuits in the US, with plaintiffs alleging it caused hair loss and scalp damage.
Where are they found?
Formaldehyde releasers are found in many water-based cosmetics, particularly rinse-off products.
Why do people avoid them?
Formaldehyde is classified as a known human carcinogen by the International Agency for Research on Cancer (IARC). It's also one of the most potent contact allergens known. Even in small amounts, repeated exposure can cause sensitization — meaning you develop an allergy that gets worse over time.
The main concerns are:
- Allergic contact dermatitis
- Scalp irritation and potential hair loss
- Respiratory irritation (especially with heat styling)
- Long-term cancer risk (at high exposures)
Hair straightening treatments like Brazilian Blowout can release dangerous levels of formaldehyde — enough to cause breathing problems for salon workers. Always ask about ingredients before salon treatments.
In Indian Products 🇮🇳
DMDM Hydantoin is common in Indian shampoos, including popular international brands sold here. Hair straightening treatments in Indian salons often contain formaldehyde — sometimes at levels that would be illegal in the US or EU. Always ask your salon what's in their keratin or straightening treatments before proceeding.
Brands to check: TRESemmé, OGX, and various salon-brand shampoos sold in India. Keratin treatments at salons may contain formaldehyde — ask before booking.
How to check your products
Look for these formaldehyde-releasing ingredients anywhere in the ingredient list.
Heat increases formaldehyde release. If you use hot tools after applying products with formaldehyde releasers, you're inhaling more of it. Consider switching to formaldehyde-free products if you heat style regularly.
Safer Alternatives
Safer preservatives include Phenoxyethanol, Sodium Benzoate, Potassium Sorbate, and Ethylhexylglycerin. Many "clean beauty" brands specifically avoid formaldehyde releasers.