You Are What You Wear

In 1941, two British chemists at Manchester’s Calico Printers Association patented a method for producing synthetic fiber from petroleum derivatives. John Rex Whinfield and James Tennant Dickson called it Terylene. DuPont acquired the rights in 1946, renamed it Dacron, and introduced it to the American public in 1951 as a miracle fabric that could be worn without ironing or wrinkling for 68 days straight.

Within two decades, the entire textile industry had reorganized itself around this discovery. Synthetic fabrics (acrylic, nylon, polyester, spandex, etc) are easy to maintain and, more significantly, cheap to produce. According to Textile Exchange data, more than 67 percent of all fiber material currently produced worldwide is synthetic, ultimately derived from the same crude oil that goes into plastics and fuels. Virgin fossil fuel-based synthetic fiber production reached 75 million tons globally in 2023, and it is forecast to more than double by 2030.

What does that have to do with your health?

What the industry does not advertise is that producing these fabrics with these properties requires not only the same crude oil that goes into plastics and fuels, but it also requires treating the resulting fabrics with various industrial chemicals that remain in the finished garment as it—constantly—contacts your skin.

Your skin blocks many substances, but the chemistry of synthetic textiles presents a different problem. A peer-reviewed study published in Environmental Science and Pollution Research took a common chemical used in synthetic textiles, benzothiazole, applied it to an artificial skin membrane, and left it there for 24 hours. During that period, 62 percent of it passed straight through.

The researchers noted this likely applies to other chemicals present in synthetic fabrics. A separate ScienceDirect study found that “skin allergenic and mutagenic halogenated pollutants occur frequently in synthetic garments” and that “hazardous chemicals are able to migrate from the textile fibers into sweat and become bioavailable.” The study found that this happens at rates up to 390 times higher than previously estimated.

This should be especially concerning for people who are otherwise quite diligent with their health—those who exercise regularly in synthetic athletic wear. Most of this type of clothing consists of acrylic, nylon, elastane, polyester and other synthetic textiles that have been treated with phthalates, bisphenols and per- and polyfluoroalkyl substances (pfas).

Researchers at the University of Birmingham found that when your skin is sweatier and more hydrated, it absorbs significantly higher levels of these chemicals at a faster rate than when your skin is dry. Researchers identify these chemical classes with concerns over endocrine disruption, neurotoxicity, obesity and cancer.

Natural fibers are as old as human civilization. They were used because they are comfortable and have quality structure.

Linen, made from flax, is naturally antibacterial and moisture-wicking, even without synthetic processing. It softens with age and resists microbial colonization through its own fiber structure.

Wool is temperature-regulating, insulating in cold, and releases heat in warmth through moisture absorption and evaporation. Merino wool tolerates direct skin contact without irritation and naturally resists odor through the actual architecture of its fibers.

Cotton is hypoallergenic, breathabl, and resists odor-producing bacteria through its adsorptive capacity, with documented clinical benefit for eczema-prone and atopic skin. The organic variety is the better choice, as conventional cotton is one of the most pesticide-intensive of all crops. Organic production removes that chemical load from both the growing process and the finished garment.

Hemp requires no pesticides to grow, improves the soil it grows in, and produces one of the most durable natural fibers available. It is naturally antimicrobial and has been in textile production across civilizations for the entirety of recorded history.

Silk is protein-based, hypoallergenic and temperature-regulating, which is why it sits against the body without irritation. Unlike synthetic fabrics, it contains none of the endocrine-disrupting compounds built into the fiber itself. Though, like other fabrics, it can carry dye chemicals, finishing agents and processing residues.

The global fashion industry generates approximately $1.7 trillion annually, which largely explains the silence on chemical use in garments. Clothing manufacturer trade groups have lobbied actively against tightening regulation, and legislation has gone nowhere. In 2006, the European Union’s reach regulation, considered the toughest chemical safety framework in the world, started with a list of 286 substances to restrict in clothing and textiles, then cut it to 33.

This is the same sequence that delayed action on tobacco, leaded gasoline and asbestos for decades after the science was clear. The research on what synthetic clothing does to the body has been accumulating for 20 years, yet production has only accelerated.

Today, researchers estimate more than 8,000 synthetic chemicals are used in clothing manufacturing. In North America, the situation is worse; the main United States chemical safety law applies almost exclusively to clothing made domestically, which covers less than 3 percent of what Americans actually wear.

What does this mean to you? Start by reading labels. Is it linen, organic cotton, wool, hemp, silk, polyester, nylon, acrylic or spandex? If it is a “blend,” remember that the percentage of the blend that is synthetic is in contact with your skin for every hour you wear it.

Remember, reading labels will tell you what fabric a garment is made from, but it will not tell you what chemicals were used to treat it. A garment marked as 100 percent cotton does not state whether it contains pfas for wrinkle resistance, formaldehyde for crease retention, or antimicrobial biocides. Some clothing companies that try to avoid chemical treatments might advertise that fact on their website, perhaps with third-party certifications. But finding garments made of natural materials is becoming more difficult, not to mention more expensive.

That being the case, prioritize natural fiber for garments that contact your skin the most and the longest: underwear, base layers, sleepwear and workout clothing.

If you exercise frequently, change out of synthetic workout clothing immediately after exercise and shower promptly to limit sweat-activated chemical absorption.

For 6,000 years, humans clothed themselves without petroleum-based fabrics. The 70-year detour into synthetic fiber has given us some clothing benefits—at the expense of our health.