Is There Formaldehyde in Hair Products?

Some hair smoothing and straightening treatments contain it. The FDA says these products often contain formaldehyde, also known as formalin or methylene glycol, and that heating the solution releases formaldehyde into the air as a gas, which stylists and clients can inhale in a poorly ventilated salon.

The FDA says airborne formaldehyde can cause serious irritation of the eyes, nose and lungs, with reported reactions including headaches, dizziness, respiratory problems, nausea, chest pain, vomiting and rash. An NIH study found that women who used hair straightening products more than four times in the previous year were more than twice as likely to develop uterine cancer as women who did not use them.

California has banned cosmetics with intentionally added formaldehyde, paraformaldehyde or methylene glycol since January 1, 2025, and Washington’s restrictions on formaldehyde releasers in cosmetics take effect on January 1, 2027. A federal rule to ban formaldehyde in hair smoothing and straightening products is still at the proposed rule stage, listed for November 2026 in the government’s regulatory agenda.

Sources checked September 15, 2026. Every point below links the page it came from.

The sources behind this answer

  • Government sourceThe FDA says hair smoothing products often contain formaldehyde, also known as formalin and methylene glycol, which is released into the air as a gas when the solution is heated. US FDA ↗
  • Government sourceThe FDA says formaldehyde released into the air can cause serious irritation of the eyes, nose and lungs, and that greater exposure means higher potential health risks. US FDA ↗
  • StudyAn NIH study found that women who reported using hair straightening products more than four times in the previous year were more than twice as likely to develop uterine cancer as those who did not use them. NIEHS, National Institutes of Health ↗
  • Regulatory filingThe FDA rule that would prohibit formaldehyde and formaldehyde-releasing chemicals in hair smoothing and straightening products is at the proposed rule stage, with the proposal listed for November 2026. Reginfo.gov, Unified Agenda ↗
  • Regulatory filingCalifornia has banned the manufacture and sale of cosmetics with intentionally added formaldehyde, paraformaldehyde or methylene glycol since January 1, 2025. California Legislature ↗
  • Regulatory filingWashington’s Department of Ecology adopted a rule restricting formaldehyde releasers in cosmetics from January 1, 2027, with retailers able to sell existing stock through December 31, 2027. Washington State Department of Ecology ↗

Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.

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