Brazilian straightening: what you absolutely should be aware of

Recently, four confirmed cases of kidney failure have been reported in connection with the brazilian straightening. This hair treatment, which has become a staple for many, poses significant problems. Smoothing, disciplining, reducing frizz, and easing styling: a dream for many of us! But behind these beautiful promises often lie substantial health risks. What is the reality? What substances should be avoided and why? Let’s break it all down for you in this article.

What is a Brazilian straightening made of?

Brazilian straightening is a keratin-based treatment, which is the protein naturally found in hair and helps to smooth the hair fiber. The hairdresser aims to achieve smoother, more flexible hair that is easier to style and frizz-free for an average of three months.

To obtain such results, you can imagine that the composition is not the best. The mixture applied to your hair acts on the hair fiber for a processing time of between 30 and 60 minutes.

The brazilian straightening mixture consists of various substances:

  • Keratin: The essential element for providing keratin to the hair fiber, smoothing it, and supposedly making the hair more resilient.
  • Amino acids: They are supposed to help nourish and restructure the hair.
  • Formaldehyde: Used to fix the keratin in the hair fiber, it is one of the most controversial ingredients since it is “thanks” to it that the hair is supposed to stay smooth for several months. The WHO (World Health Organization) has classified it as a carcinogenic substance.
  • Glyoxylic acid: Used as an “alternative” to formaldehyde, it temporarily modifies the hair structure. However, an alternative is expected to be healthier, right? This is not necessarily the case with glyoxylic acid. Recent studies have shown it to be linked to cases of kidney failure.
  • Silicones and oils: Silicones and oils are often added to provide shine and protect the hair from external aggressions.
  • Preservatives: Preservatives are used to extend a product’s shelf life. Some of the most common include parabens, sulfates, and synthetic preservatives like phenoxyethanol.
  • Smoothing agents: Some brazilian straightening treatments, particularly those aimed at smoothing very curly hair, contain strong chemical agents such as sodium hydroxide.
  • Emollients and conditioners: Emollient agents are added to soften the hair and facilitate detangling. They help reduce frizz and make hair easier to style.
  • Fragrances: Fragrances are often added to give the product a pleasant scent, masking the strong odors of certain chemical ingredients like glyoxylic acid or formaldehyde.

A hair treatment that claims to work wonders on your hair inevitably includes a lengthy list of ingredients. So, what is the real danger of Brazilian straightening?

Brazilian straightening risks: Avoid formaldehyde and glyoxylic acid to preserve your health

Formaldehyde has been known as a dangerous component for years. The WHO (World Health Organization) classified it as a carcinogen for humans (Group 1) in 2024. This means there is enough evidence showing that prolonged exposure to formaldehyde increases the risk of developing certain cancers, including respiratory tract cancers and leukemia. According to the INRS (National Institute for Research and Safety), formaldehyde is considered “flammable, corrosive, and toxic“. Additionally, some symptoms such as eye and skin irritations, coughing, breathing difficulties, and allergies can also occur.

What about glyoxylic acid?

Since the beginning of the year, the Anses (National Agency for Food, Environmental and Occupational Health Safety) has received four reports of acute kidney failure related to the use of Brazilian straightening products. Three poisonings occurred between January and August 2024, with a fourth case reported in October. However, the actual number of affected individuals may be much higher.
In-depth studies are currently being conducted by Anses. While these studies are ongoing, the agency urges caution and advises against the use of straightening products containing glyoxylic acid.
If this ingredient sounds familiar and you believe you might be exposed to glyoxylic acid, be aware that signs of kidney failure can appear a few hours after exposure. Symptoms include abdominal or lower back pain, nausea, and/or vomiting. It is imperative to consult a doctor if you experience any of these symptoms or to contact a poison control center, specifying the use of Brazilian straightening.

Stop Brazilian straightening and favor gentle, natural care

Just because you want to take care of yourself doesn’t mean you have to expose yourself to risks. It is imperative and urgent to prioritize your health first. Cases of kidney failure should be taken seriously, as anyone can find themselves in this situation. Four reported cases in less than a year is quite significant and can be alarming.

You can maintain your hair safely with healthy, natural professional products. Be careful to choose products that are TRULY ecological, such as those certified by an ecological label. Hairborist products are certified by Ecogarantie, the strictest label in Europe, a true guarantee of quality.

Goodbye to Brazilian straightening, chemical coloring, and harmful hair treatments. Say hello to natural products with transparent compositions and natural hair dye.
Believe us, you’ll soon be able to do without Brazilian straightening. Instead, we offer treatments that truly respect your scalp and health. And if your hair is healthy, you won’t need to treat it with chemical products as often.
Our organic and natural range is here to revive your hair, as all our products are safe and non-aggressive. It’s very important to integrate such care into your hair care routine. Thanks to their plant-based active ingredients, our products make hair more flexible, shinier, and help manage frizz in the long term. Brazilian straightening, on the other hand, gives the illusion of healthier, smoother hair in the short term, but actually damages it in the long run.
Remember one thing: the best ingredients are always found in nature!

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