Want perfectly straight hair? The price can be very high. New research shows that popular straightening treatments like keratin straightening or Brazilian blowouts may be dangerous not only for your hair, but also for your life.
Scientists warn: such products often contain formaldehyde or substances that release it when heated by an iron. Formaldehyde is a toxic gas officially recognized as a carcinogen. When inhaled, it can cause not only eye irritation, coughing and dizziness, but also increase the risk of certain cancers. Regular use of chemical straighteners is associated with an increase in the risk of pancreatic cancer by more than 100%, thyroid cancer by more than 70%, as well as lymphoma. This is quoted by the media, citing the results of recent works in the field of oncological epidemiology, which studied long-term contact with formaldehyde vapors and other toxic components.
In the US, regulators have been trying to ban such formulations for several years. The Food and Drug Administration (FDA) has publicly warned that when these mixtures are heated, formaldehyde is released into the air, and if the salon is poorly ventilated, both the master and the client simply breathe in the carcinogen. Prolonged contact is associated not only with an increased risk of some types of cancer, but also with nervous symptoms, breathing problems, and scalp burns. Because of this, the FDA has proposed to limit or outright ban such products, but there are still “keratin” and “Brazilian blowouts” on the market that emit formaldehyde.
The problem is not limited to “in-salon formaldehyde.” What is advertised as “safe formaldehyde-free straightening” is not necessarily safe either. In 2025, toxicologists described cases of acute poisoning and even kidney damage after procedures using glyoxylic acid-based products, a popular alternative to formaldehyde. Patients after such treatments complained of vomiting, abdominal pain, and a rash on the scalp; most of them recorded acute kidney damage. The study authors warn: the “formaldehyde free” marker does not mean “healthy.”
A separate risk area is hair coloring and perming. Dyes may contain aggressive oxidants (ammonium, peroxide), which cause chemical burns to the scalp and allergic reactions. Cosmetologists also pay attention to parabens and other so-called endocrine disruptors in straightening products: there is evidence that they can affect hormonal levels, weight, and fertility.
Even basic care is not always safe. Conventional shampoos and styling products still contain preservatives that gradually release formaldehyde, as well as parabens. A 2025 study showed that more than half of the women in the sample regularly use products with such ingredients, often without even knowing it, because the word “formaldehyde” is not written directly on the label - other chemical names are used.
What doctors advise:
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do not inhale "keratin" fumes - require ventilation, a mask, or refuse the procedure;
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read the composition and avoid the words formaldehyde, formalin, methylene glycol, DMDM hydantoin (this is a preservative that releases formaldehyde);
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do not do aggressive straightening often and do not carry out such procedures at home without protection;
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If you experience burning eyes, coughing, or rashes after using the salon, consult a doctor immediately.
Beauty is definitely not worth the risk if you have to breathe in a carcinogen for it.
