Written By: GreenMedInfo Research Group

She just wanted to style her hair, but what she got instead was recurrent acute kidney failure and a brush with death. The culprit? A common chemical lurking in many hair straightening products that millions of women use every day, oblivious to the potential dangers.

A disturbing new trend is emerging that links certain popular hair straightening treatments to episodes of acute kidney failure, particularly in young women. The danger lies with products containing significant concentrations of glyoxylic acid, which can be absorbed through the skin during the lengthy hair straightening process and wreak havoc on kidney function.1

In a recent case reported in the New England Journal of Medicine, a 26-year-old woman with no prior health issues experienced three separate episodes of severe acute kidney injury, each one occurring shortly after she had undergone a hair straightening treatment at a salon.1 She developed painful symptoms like vomiting, fever, and back pain within hours of the procedures. Blood tests revealed highly elevated creatinine levels, indicating her kidneys were failing. Yet, between exposures, her kidney function would return to normal.1

To investigate if the hair products were indeed responsible, the French researchers applied the straightening cream used on the woman to laboratory mice. The results were striking - within just 24 hours, the mice developed kidney failure, and analysis found oxalate crystal deposits throughout their kidney tubules,1 which are the hallmarks of acute oxalate nephropathy.2

Here's what happens: Glyoxylic acid is a key ingredient in many "formaldehyde-free" hair straighteners and smoothing products. When absorbed through the skin, it is rapidly metabolized into oxalate.1 Oxalate is usually excreted in urine, but if the load is too high, such as with excessive absorption of glyoxylic acid, the oxalate binds to calcium in the kidneys and forms insoluble crystals.2 These sharp crystals physically damage the delicate tubules that are vital to kidney function.3 Enough damage leads to kidney failure.

Younger women may be especially at risk. Their skin tends to be more permeable than older adults, allowing for greater absorption of topical agents.4 The woman in this case also experienced a burning sensation and developed a rash during the hair treatments,1 signs that the product was breaking down her skin's barrier. However, even visibly intact skin will still absorb a percentage of glyoxylic acid when exposed for the lengthy durations common in straightening treatments, which can be 1-5 hours or more.5

What makes this doubly concerning is that acute kidney injury can often go undiagnosed, as symptoms like nausea and fatigue are non-specific.3 Even in the case study, it took three separate incidents of exposure and injury before the connection to the hair treatments was made.1 How many other cases of "mystery" kidney failure in young women could be traced back to their salon if doctors knew to ask?

Unfortunately, the concentrations of glyoxylic acid in hair products are poorly regulated. Alarmingly, the French researchers found some commercial formulations with up to 17% glyoxylic acid and a pH less than 2.1 At those levels, it doesn't take much exposure for dangerous amounts to enter the bloodstream. Yet, women are using these products without any warning of potential kidney risks.

Admittedly, not every woman who gets a hair straightening treatment will develop kidney failure. There are likely genetic differences in how people's bodies metabolize and handle glyoxylic acid and oxalate.5 But for those who are susceptible, the results can be devastating. No one should have to trade their kidney health for smoother hair.

More studies are urgently needed to quantify the risks based on duration and frequency of glyoxylic acid exposure, product pH and concentration, and application practices. But in the meantime, regulatory agencies must demand better labeling and warnings on these products about the kidney dangers. The cosmetic industry has a responsibility to protect, not harm, its customers. And consumers have a right to make informed choices about what they put on their bodies. Hopefully, awareness and action now can prevent further unnecessary damage from a seemingly innocuous beauty treatment. No head of glossy hair is worth gambling with kidney failure.

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