
A number of hair styling products are actually harmful to health. This includes hair straighteners, which contain chemicals hazardous to both the hairdresser applying the products, as well as the woman that is using the product in her hair. These products are especially harmful if the woman using or applying the product is pregnant (it will go to the fetus) or breastfeeding (chemicals get into the mother's breastmilk).
A number of health risks are already known from chemicals (e.g., forever chemicals, formaldehyde) in such products, such as increased risks of certain cancers. But now there is an additional concern.
A 2024 study found that hair-straightening products containing glyoxylic acid was associated with a risk for acute kidney failure. This is because it resulted in the accumulation of calcium oxalate crystals in the kidneys. While the study was done on mice, the researchers thought this could explain cases of renal damage in young women. For example, one woman who became very ill with acute renal damage after each visit to a hair salon - where she had her hair straightened.
Similar cases have been noted elsewhere after women getting their hair straightened in hair salons. Black women are especially at risk because of their frequent use of such products. [Site with more information.]
According to the researchers, it is the glyoxylic acid that is problematic, but not glycolic acid.
Glyoxylic acid is found in some cosmetic products (such as shampoo, styling lotion, and straightening products) - generally as a replacement for formaldehyde (which is irritating and carcinogenic). However, glyoxylic acid is recommended to avoid contact with the scalp. (So why is it in the products!!??)
From Medscape: Hair-Straightening Products Entail Acute Kidney Failure Risk
The use of hair-straightening products containing glyoxylic acid is associated with a risk for acute kidney failure because of the accumulation of calcium oxalate crystals in the kidneys. The observation was made by a team of French researchers who tested the suspected straightening product on animals. The product is believed to be the cause of several episodes of renal damage in a young woman. ...continue reading "Hair Straighteners and Kidney Harm"