Polyester (polyethylene terephthalate or PET) is a synthetic polymer widely used in clothing due to its durability and low cost. This widespread use has raised questions about its safety, particularly concerning chemicals that interfere with the body’s endocrine system. The concern centers not on the polymer structure itself, but on the chemical additives and residues incorporated during manufacturing and finishing. Understanding these interactions is important for assessing the potential for textile-based exposure to substances that may affect human hormones.
Chemicals Used in Polyester Manufacturing
The production of polyester involves a complex chemical process that introduces substances beyond the base plastic polymer, some of which are known endocrine disruptors. Antimony Trioxide is a primary concern, commonly employed as a catalyst to speed up the polymerization reaction of PET. This heavy metal can remain embedded within the finished fabric and is classified as a possible human carcinogen. Scientific testing confirms that a small amount of antimony can leach from polyester textiles, especially when subject to moisture and friction.
Beyond the catalyst, other chemical agents are often applied to achieve desired fabric performance characteristics. These include Bisphenol A (BPA), a well-documented endocrine-disrupting chemical that mimics estrogen, detected in some polyester-spandex blends. Phthalates are sometimes used as plasticizers in printing inks and are also linked to hormonal imbalances. Finishing agents like formaldehyde (for wrinkle resistance) and Per- and Polyfluoroalkyl Substances (PFAS) (for stain resistance) can also be present.
Residual dyes and flame retardants represent another layer of chemical exposure risk, as many of these compounds are suspected of interfering with the endocrine system. The overall chemical residue profile depends heavily on the specific manufacturing processes and finishing treatments applied. The potential for these substances to migrate from the fabric into the body is the primary mechanism of concern.
How Polyester’s Physical Properties Affect Skin Exposure
The physical structure of polyester fabric contributes to the potential for chemical exposure by altering the microenvironment between the fabric and the skin. Polyester is hydrophobic, meaning it repels water and does not readily absorb moisture like sweat. This property causes sweat to remain on the skin’s surface and trapped against the body, creating a high-humidity layer.
This trapped moisture and the fabric’s inherent lack of breathability lead to an increase in localized skin temperature, especially during physical activity. The combination of elevated temperature and high humidity enhances the rate of dermal absorption for many chemicals. Warm, moist skin acts as a more permeable barrier, allowing residual chemicals to transfer more easily from the fabric to the body.
The physical friction of the fabric against the skin during movement, particularly in tight-fitting athletic wear, further compounds this effect. This continuous mechanical action promotes the release of chemical residues from the textile fibers into the warm, moist layer of sweat. The physical properties of polyester thus create a scenario conducive to the transfer and absorption of chemical additives into the wearer’s body.
Systemic Risk from Microplastic Shedding
A distinct concern from direct skin exposure is the systemic risk posed by the microplastic fibers shed from polyester textiles during wear and washing. Polyester clothing releases thousands of tiny synthetic fibers, or microplastics, with every laundry cycle, which ultimately enter the environment. These minute plastic particles are now ubiquitous, found in air, water, and even human tissues.
Internal exposure occurs primarily through the inhalation of airborne microplastic fibers, which settle in household dust, and the ingestion of particles found in food and drinking water. Once inside the body, these microplastics present a physical risk, potentially triggering chronic inflammation in the lungs or digestive tract.
Furthermore, microplastics act as transport vectors for environmental toxins because their plastic surfaces readily absorb persistent organic pollutants (POPs) from the surrounding environment. Chemicals like polychlorinated biphenyls (PCBs) or heavy metals can adhere to the microplastic fibers. When these contaminated fibers are inhaled or ingested, they deliver a concentrated dose of these environmental toxins, which are often endocrine-disrupting, directly into the body’s systems.
Safer Alternatives and Mitigation Strategies
Consumers can reduce their potential exposure to textile-based chemicals and microplastics by making informed fabric choices and adopting simple washing practices. Opting for clothing made from natural, plant-based fibers significantly reduces the reliance on synthetic materials and associated chemical additives. Excellent alternatives include:
- Organic cotton, grown without harsh pesticides.
- Linen.
- Hemp.
- Tencel (Lyocell), known for breathability and minimal chemical finishing.
For garments that must be purchased in polyester, washing new clothes before wearing them can help leach out some of the residual manufacturing chemicals. Avoiding the use of fabric softeners and high-heat drying, which can damage the fibers and potentially increase chemical release, is also a useful mitigation step. When exercising, choosing looser-fitting styles or wearing polyester only as an outer layer can reduce direct, prolonged skin contact in high-sweat areas.