Some hair-straightening products can cause kidney failure – pioneering Israeli study

Israel 1st country to ban treatments with glyoxylic acid which gets absorbed in skin, causing pain, vomiting, and harm to kidneys; researchers anticipate global awareness

Nathan Jeffay is The Times of Israel's health and science correspondent

Illustrative: A hair stylist combs through hair after using a treatment for long-term straightening. (Andrii Borodai via iStock by Getty Images)
Illustrative: A hair stylist combs through hair after using a treatment for long-term straightening. (Andrii Borodai via iStock by Getty Images)

Some salon hair-straightening treatments can cause kidney failure, according to recent research by Jerusalem doctors which has prompted Israel’s Health Ministry to ban a host of products.

Israel is the first country to document numerous cases, and to ban products, according to Prof. Linda Shavit of Shaare Zedek Medical Center, who led the research.

Last month, the Health Ministry in Jerusalem banned all products that contain the offending ingredient, glyoxylic acid, based on a preview of the research, which has since been published in the American Journal of Kidney Diseases.

Shavit believes that the publication of the research will prompt doctors around the world to start asking patients with kidney failure — especially young women, who make up the majority of the hair-straightening clientele — if they have undergone such treatments.

Many new cases of hair straightening-induced illness will be discovered, she predicted.

“We documented 26 cases of acute kidney injury over the last three years, and since the research was conducted the number of cases in Israel has risen to 38 people,” she told The Times of Israel on Thursday. “Though we suspect this is just the tip of the iceberg for Israel, and believe there are many cases elsewhere.”

The patients in the study experienced abdominal pain, nausea, vomiting, and scalp rash after using the hair straightening products. The average age was 28, most had no previous medical problems, and one of the women — all patients were female — was pregnant.

Illustrative image – human kidneys (Mohammed Haneefa Nizamudeen visa iStock by Getty Images)

“None of them died and the damage was reversible, but three young ladies were on dialysis for several weeks, and a few needed kidney biopsies which are invasive. Some spent time in intensive care, so this is serious,” said Shavit.

The products in question contain glyoxylic acid, a common ingredient in creams for so-called permanent hair-straightening, which lasts for several months. The creams are normally applied in salons but are occasionally used by people at home.

“What we saw is that glyoxylic acid can absorb into the skin, and once in the bloodstream it can metabolize to oxalate, then go to our kidneys and cause damage,” Shavit explained, adding that this conclusion is based on detailed research on multiple patients, including via biopsies. Oxalate is a naturally occurring molecule, which in excessive quantities can cause kidney failure.

Prof. Linda Shavit of Shaare Zedek Medical Center (courtesy of Shaare Zedek Medical Center)

She said that since dozens of patients who used the products had to undergo medical treatment in hospital, it is likely that the chemicals have already damaged the kidneys of many other people who are unaware. “What we documented may only be some of the cases,” Shavit suggested.

“There were probably a lot of mild cases that didn’t get to a hospital. There may be many women who are asymptomatic but who have kidney damage as a result of these products,” she said.

Shavit believes that the Israeli ban on treatments with glyoxylic acid will save lives, and is hopeful that all salons will observe it and refrain from using these products.

“It is important to raise the awareness of women as well as stylists and hair stylists to use only permitted treatments and to adhere to the manufacturers’ instructions,” she asserted.

“I’m glad that we were able to prevent many more life-threatening cases in women who [were looking] to undergo hair straightening with safe materials.”

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