A recent scientific study has found that some people have up to a crayon’s worth of plastic in their brains. How is it getting there? A 2023 study revealed that human sweat can extract toxic chemicals from microplastics, potentially making them available for absorption through the skin. This discovery raises serious concerns about the synthetic materials we wear every day like yoga pants and synthetic underwear.
Researchers at the University of Birmingham tested common plastic microfibers in a lab using synthetic sweat. Their findings, published in Environmental Science and Technology, showed that brominated flame retardants—chemicals commonly used to enhance plastic performance—leached out of the microplastics upon contact with sweat. These chemicals, previously linked to neurotoxicity, reproductive harm, and cancer in animal studies, could now pose direct risks to human health.
Polyethylene microplastics were found to release the highest levels of these toxic additives. Alarmingly, our skin is in constant contact with microplastics—not only from clothing but also from dust, plastic aligners for our teeth, cosmetics, and even the air we breathe.
Related: a new study says some of us have a crayon worth of plastics in our brain
Dr. Mohamed Abdallah, a lead researcher on the study, emphasized that human sweat contains oily components that accelerate the leaching process, making these chemicals more readily available for skin absorption. With microplastics already widespread in our environment, the clothing we choose matters more than ever.
“Because toxic flame-retardant chemicals are hydrophobic, it wasn’t clear if they would leach out of the microplastic to human sweat. However, human sweat is a complex mixture that contains oily components known as sebum, which facilitated the leaching of toxic chemicals from microplastics, rendering them available for absorption through the skin.
“With this new evidence, policy makers need to seriously consider the risks of microplastics and human contact with them on a regular basis. We will be continuing to research how these chemicals that can be leached through contact with sweat may be absorbed by human skin on a daily basis.”
Fast Fashion’s Hidden Risk
Synthetic clothing, often made from polyester, nylon, and acrylic, sheds microplastics with every wash and wear. Now, evidence suggests that these plastic fibers could be releasing harmful chemicals directly onto our skin—especially when we sweat.
The study also found that antiperspirants and foundation increased the bioaccessibility of certain toxic chemicals, making it even easier for them to enter the body. Smaller microplastic particles (0.45mm) doubled the rate at which these chemicals leached out compared to larger particles (4mm), suggesting that prolonged exposure to plastic-based fabrics could worsen the risks.
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Natural fibers like organic cotton for clothing and bedding, hemp, and wood-based fabrics such as Tencel and modal offer a safer, breathable alternative to synthetic materials. These fabrics don’t shed microplastics, don’t contain toxic flame retardants, and allow your skin to breathe without the risk of chemical exposure.
As evidence grows about the dangers of microplastic exposure, it’s time to rethink the fabrics we wear daily. Choosing natural fibers isn’t just an eco-friendly decision—it’s a choice for better health.
Love our findings? We have a whole series of microplastics risks, worries and solutions here
