Hair straightening had a strong effect on kidney health
French doctors have described three cases of acute kidney damage in the same young woman that occurred immediately after a hair straightening procedure. As reported in The New England Journal of Medicine, glyoxylic acid from a hair straightening product played a major role in this pathology.
Recently, Israeli scientists described 26 patients who experienced acute kidney damage after a "Brazilian" hair straightening procedure. The authors hypothesized that glycolic acid derivatives found in hair straightening products may be absorbed through the skin and metabolized by the liver to oxalates, leading to calcium-oxalate nephropathy. However, there is insufficient evidence that glycolic acid, a constituent of many cosmetic products, can cause acute kidney damage after absorption through the skin.
A team of doctors led by Emmanuel Letavernier of Sorbonne University described several cases of acute kidney damage in one patient after a hair straightening procedure. The patient was a 26-year-old Tunisian woman with no previous health problems. She had three consecutive episodes of acute kidney injury (June 2020, April 2021, and July 2022) that occurred immediately after (same day) hair straightening procedure. During the procedure, she complained of burning sensation followed by sores on her scalp. The cream used for the straightening procedure contained glyoxylic acid but no glycolic acid.
The disorder was accompanied by vomiting, diarrhea, fever, and back pain. Laboratory tests showed elevated plasma creatinine levels during each episode. Computed tomography showed no evidence of obstructive uropathy, and urinalysis confirmed the presence of blood and leukocytes without protein or bacteria; no tests for crystals in the urine were performed. At the same time, renal function recovered rapidly after each episode.
To investigate a potential mechanism of acute kidney injury, the clinicians applied the investigational straightening agent to the backs of the mice (control mice received petroleum jelly). Urinalysis performed the day after application of the remedy showed the presence of elongated calcium oxalate monohydrate crystals similar to those typically seen after ethylene glycol intoxication. Plasma creatinine levels in experimental mice were significantly elevated 28 hours after application of the remedy to the skin. Three-dimensional computed tomography of the kidneys showed the presence of dense deposits of calcium oxalate monohydrate in the tubules of the nephrons.
Doctors believe that glyoxylic acid from the hair straightening product is responsible for the calcium oxalate-induced nephropathy. Notably, this acid was recently introduced in hair straightening products as a safer alternative to formaldehyde. Doctors believe that regulators should pay attention to the safety profile of glyoxylic acid and, if necessary, remove products containing it from the market.
Regulators may first have to deal with microplastics, which are also harmful to health. For example, we recently reported that polyethylene and polyvinyl chloride microparticles in carotid atherosclerotic plaques increase the risk of cardiovascular death.