DMDM Hydantoin is a preservative used in certain shampoos, conditioners, and other hair care products. DMDM Hydantoin functions as a formaldehyde releaser or donor. It works by slowing releasing formaldehyde over time to prevent the growth of harmful mold and bacteria as well as other microbes, therefore increasing the shelf-life of cosmetic products. According to a study done by the Actas Dermo-Sifiliográficas in Spain, the chemical has increased the risk of contact dermatitis and irritation in consumers who are already sensitive to formaldehyde exposure.
The FDA lists DMDM hydantoin as a common allergen in personal care products. Current research on the chemical has produced varying perspectives. Formaldehyde is a known carcinogen. At high concentrations, it can cause chemical burns, though this is mostly an occupational hazard. A 1998 safety assessment found the chemical to be safe as a cosmetic ingredient at concentrations up to 1%. However, a more recent 2016 study found that formaldehyde releasers can lead to irritation at low levels of exposure. Still, other doctors claim that the levels of formaldehyde that DMDM hydantoin releases is negligible and should not be causing irritation on its own. However, this also depends on one’s sensitivity to formaldehyde; up to 11.9% of the population is allergic to formaldehyde when exposed to a 2.0% formaldehyde patch test. Sensitivity can also develop over time with repeated exposure.
DMDM hydantoin is the current focus of class-action lawsuits against Johnson & Johnson as well as Unilever. Plaintiffs are claiming that exposure to the preservative has caused hair loss and irritation. Plaintiffs have filed two class-action lawsuits against Unilever who manufactures the TRESemmé line of hair products. The suits allege that Unilever misrepresented their product and did not adequately warn consumers of the chemical and the hair loss it could cause. Plaintiff Emily Castillo claimed that Unilever had misrepresented their TRESemmé Keratin Smooth Color Shampoo as being safe and effective. Rather than helping nourish her hair, the shampoo allegedly caused scalp irritation and hair loss.
Similarly, plaintiff Larissa Whipple has sued Johnson & Johnson for their OGX hair care products, claiming affirmative misrepresentations where the company claimed the products would nourish, cleanse, and repair hair. Instead, they have allegedly caused hair loss and scalp irritation for thousands of consumers. Johnson & Johnson had initially announced in 2012 that they would remove DMDM hydantoin from their products by 2015, claiming that it did not meet their safety and care commitment guidelines. The company later clarified that the chemical would still be used in a “small number” of their products. Ultimately, is DMDM hydantoin extremely dangerous? The jury is still out, in both a scientific and a legal sense. More research is needed to establish a stronger link between the formaldehyde releaser and potentially carcinogenic effects. The pending class action lawsuits are still awaiting class certification, as well. Only time will tell, but it seems prudent to pick hair care products with less potentially harmful preservatives.