FDA Proposal Would Ban Formaldehyde Only in Heated Hair Smoothing and Straightening Products

The Food and Drug Administration has drafted a rule to prohibit formaldehyde and formaldehyde-releasing chemicals in hair smoothing and straightening products sold in the United States. The proposal applies narrowly to products that are applied to hair and then heated under their conditions of use, not to cosmetics in general or to every product that contains formaldehyde-releasing preservatives.

The agency published the proposed rule on the federal regulatory agenda under the title "Use of Formaldehyde and Formaldehyde-Releasing Chemicals as an Ingredient in Hair Smoothing Products or Hair Straightening Products." The rule would ban formaldehyde itself, along with methylene glycol and other formaldehyde-releasing compounds, from this specific category of cosmetics. FDA describes these products as being applied to human hair as part of a treatment that combines chemical application with heating tools to smooth or straighten.

What "Heated Under Conditions of Use" Means

The critical scope limitation appears in FDA's own description: the products in question are those "applied to the hair and heated under their conditions of use." This distinguishes professional salon treatments, where a stylist applies a formaldehyde-containing solution and then seals it with a flat iron or blow dryer at high temperatures, from leave-in conditioners or styling creams that air-dry on the shelf.

Certain hair smoothing treatments have drawn regulatory attention for years because this heating step converts liquid formaldehyde or methylene glycol into formaldehyde gas. The resulting vapor is what exposes both salon workers and clients to elevated levels of the chemical. Products that contain formaldehyde but are not designed to be heated during use fall outside the proposed prohibition.

The agency regulates these cosmetics under the Federal Food, Drug, and Cosmetic Act and, for retail products, the Fair Packaging and Labeling Act. FDA has maintained a consumer page on hair smoothing products since at least 2021, warning that some products "contain or release formaldehyde" when heated.

The Health Effects Cited by FDA

The agency's case for the ban rests on both short-term and long-term health effects. According to the regulatory agenda, FDA links use of these hair smoothing products to immediate adverse effects including sensitization reactions and breathing problems. Sensitization means that repeated exposure can trigger allergic responses to formaldehyde, even at levels that previously caused no reaction.

The longer-term risks include an increased risk of certain cancers. This aligns with known carcinogenic effects of formaldehyde, though FDA's proposal does not hinge on new agency research. Instead, the regulatory justification cites established health data about formaldehyde exposure.

The exposure route matters here. Consumers and salon workers inhale formaldehyde gas released during the heating step, not merely the liquid product applied to hair. This distinction has complicated enforcement in the past, because some manufacturers argued their products were "formaldehyde-free" when they contained methylene glycol, which releases formaldehyde upon heating.

How to Spot These Ingredients on Labels

FDA has told consumers to look for specific ingredient names. Formaldehyde may appear directly on packaging or company websites. It may also be listed as formalin, which is a solution of formaldehyde in water and methanol, or as methylene glycol, a chemical that converts to formaldehyde when heated.

The agency's 2021 consumer guidance states plainly: if a hair smoothing product lists any of these three names, "that means the product contains formaldehyde or will release formaldehyde." This direct line to consumer decision-making suggests FDA has found label obfuscation to be a persistent problem in this product category.

The consumer materials also discourage purchasing or using formaldehyde-containing hair smoothing products for home use. This warning acknowledges that some keratin treatment kits are sold directly to consumers, creating exposure risks in residential bathrooms without professional ventilation systems.

What Remains Outside the Proposal

The proposed rule does not constitute a blanket ban on formaldehyde in cosmetics. Formaldehyde-releasing preservatives such as DMDM hydantoin, imidazolidinyl urea, and quaternium-15 appear in numerous shampoos, conditioners, and lotions as antimicrobial agents. These preservatives slowly release small amounts of formaldehyde to prevent bacterial growth, but they are not typically heated during use in ways that generate significant vapor exposure.

Whether such preservatives in rinse-off products would fall under this prohibition depends on whether FDA interprets them as ingredients in "hair smoothing or hair straightening products" and whether those specific products are "heated under their conditions of use." The regulatory agenda language does not expressly exclude all cosmetic preservatives from the rule, but the scope definitions appear to limit it to the smoothing/straightening product category.

The proposal also does not address salon ventilation requirements or workplace exposure limits, which fall primarily under Occupational Safety and Health Administration jurisdiction. FDA's authority here is over product composition and marketing, not workplace conditions.

Questions the Rule Leaves Unanswered

Several edge cases remain unclear from the materials published to date. FDA has not released full proposal text explaining whether the agency treats airborne formaldehyde exposure as distinct from liquid product contact, though the heating condition suggests vapor is the concern. The precise regulatory language separating rinse-off shampoos with formaldehyde-releasing preservatives from heated smoothing treatments has not been located in primary sources.

Whether the proposal expressly excludes general cosmetic preservatives outside the hair smoothing category, and the final status of any Federal Register publication, also require verification against the official rule text rather than agenda summaries. The sources identified here are regulatory agenda entries and consumer guidance pages, not the proposed rule itself.

What is established: FDA is targeting a specific product-application combination—formaldehyde-containing solutions heated onto hair during smoothing or straightening treatments—not every cosmetic that touches formaldehyde chemistry. Anything beyond that boundary awaits the full proposal text and any public comment period that follows.

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