Endocrine disruptors in activewear: what founders actually need to spec

The chemical reality nobody wants to talk about

Somewhere between the moisture-wicking marketing copy and the four-way stretch, there's a chemistry problem most activewear brands don't address. The fabrics that perform well in the gym are frequently the same fabrics that carry compounds linked to hormonal interference.

This isn't fearmongering. It's mechanism.

Most fitness professionals live in their activewear practically 24/7. Recent testing conducted by the Center for Environmental Health (CEH) in Oakland, California, discovered high bisphenol A levels (BPA) in athletic clothing that contains spandex in combination with polyester. Research has shown that some polyester-based activewear can expose wearers to BPA levels up to 40 times the safe limit.

The issue isn't acute toxicity. It's chronic, cumulative load. PFAS bioaccumulate over time, meaning the person who has been wearing performance activewear daily for 20 years carries a higher body burden than someone who started recently. Cumulative exposure matters.

For founders building activewear brands, this is both a product risk and an opportunity.

The compounds: what actually shows up in activewear fabrics

BPA and bisphenol variants

BPA is an industrial chemical used to make polycarbonate plastics and epoxy resins. Many people don't realize that it is widely used in manufacturing synthetic fabrics including polyester, nylon and spandex. Manufacturers use BPA to coat fabric fibers to strengthen them for easier production.

The primary concern with BPA is that it's a known endocrine disruptor. This means it can mimic or interfere with your body's hormones, particularly estrogen. Studies show that BPA is an "endocrine disruptor," which means that it interacts with estrogen, androgen and thyroid hormone receptors.

OEKO-TEX tightened BPA limits in 2025. Some recycled polyester garments have been found to contain higher bisphenol levels than virgin fibers. This is critical for founders using recycled content as a sustainability claim. The recycled feedstock may introduce contaminants not present in virgin material.

PFAS: the water-repellent problem

PFAS are a group of human-made chemicals widely used in textiles to impart water, oil and stain repellency, or soil release. In the apparel industry, they've long been valued for enhancing fabric durability and performance. Often referred to as "forever chemicals," PFAS are highly persistent in the environment.

The regulatory landscape is shifting fast. In 2026 alone, new PFAS restrictions took effect across multiple U.S. states and European countries, with additional deadlines approaching throughout the year. For the fashion and textile industry, compliance is no longer a future concern.

The EU has banned intentionally added PFAS in all textile articles from January 2026, with outdoor apparel for severe wet conditions requiring a "Made with PFAS chemicals" disclosure. California AB 1817 bans intentionally added PFAS in textiles. The total organic fluorine threshold drops from 100 ppm to 50 ppm in January 2027.

For brands selling into multiple markets, the compliance burden is multiplying.

Phthalates and formaldehyde

Phthalates are plasticizers commonly found in synthetic textiles and printed graphics on activewear. They are known endocrine disruptors that can interfere with testosterone production and reproductive development. Like BPA, phthalates can migrate from fabric to skin, particularly in warm, moist conditions.

Formaldehyde is used in some textile finishing processes to make fabrics wrinkle-resistant and colorfast. It's classified as a known human carcinogen by the International Agency for Research on Cancer. While concentrations in clothing are typically low, prolonged skin contact, particularly during sweating, raises the potential for absorption.

Why activewear is different from other apparel categories

The skin is the largest organ. Nearly 20 square feet of absorptive surface. Highly vascularized. Dense with sensory and immune receptors. What gets absorbed doesn't stay local. It enters systemic circulation.

Heat opens pores, increases blood flow to the skin, and makes your body more absorbent. This is exactly when you're most likely to be wearing synthetic activewear in direct contact with hormone-sensitive areas like the groin and underarms.

All synthetic garments shed microplastics, but activewear is a particularly significant source for several reasons: washing frequency (most people wash synthetic activewear after every use), fabric structure (performance activewear often uses finer, looser-knit fabrics engineered for stretch and wicking that shed more fibres than tightly woven materials).

Activewear is worn 12 to 16 hours a day by many consumers. The exposure window is long. The proximity to hormone-sensitive reproductive tissues is direct. The conditions, heat and sweat, are exactly what increases dermal absorption.

"No other generation in human history has had this level of synthetic chemical contact with reproductive organs."

The Australia angle: what's changing locally

2025 was a significant year for the regulation of PFAS in Australia. The release of the National Environmental Management Plan 3.0, a ban on key PFAS chemicals under the Industrial Chemicals Environmental Management Standard, updated drinking water guidelines, and the final report of the Senate Select Committee on PFAS have collectively reshaped the national regulatory landscape.

The Heads of EPA Australia and New Zealand have agreed to the publication of an update to the PFAS National Environmental Management Plan (PFAS NEMP 3.1). The PFAS NEMP 3.1 was released on 2 June 2026.

Three groups of PFAS representing around 500 individual substances have been scheduled under the scheme: PFOS, PFOA, PFHxS and related chemicals. A ban on the import, use and manufacture of these PFAS came into effect from 1 July 2025.

For Sydney-based founders importing activewear through Port Botany, this regulatory shift has direct supply chain implications. Port Botany handles 95% of NSW containerized trade. Textiles and apparel from Chinese garment manufacturers serving Australian retail chains flow through this port. If your fabric contains scheduled PFAS compounds, you have a compliance problem at the border.

The Sydney apparel scene has been watching this closely. Global Sourcing Expo Sydney returned from June 16-18 at ICC Sydney with over 600 exhibitors from multiple countries showcasing apparel, textiles, accessories and footwear. The event featured sourcing seminars, AI and sustainability discussions. Conversations about PFAS compliance and chemical transparency were prominent.

A worked example: a Sydney founder reformulating

Imagine a Sydney-based founder, let's call her Mira, who launched an activewear label two years ago. She's been sourcing nylon-spandex fabrics from a Taiwanese mill, using a DWR (durable water repellent) finish for her leggings. Her leggings perform well. Customers love them. The problem: that DWR finish is C6 fluorotelomer-based. Not a long-chain PFAS, but still regulated under the new EU restrictions she needs for her European wholesale accounts.

Mira has two options:

1. Switch to a non-fluorinated DWR. Silicone-based or dendrimer-based alternatives exist. They perform differently. Wash durability is lower. But they clear regulatory thresholds.

1. Eliminate the finish entirely and reformulate the base fabric. This is the harder path, but it's also where the opportunity sits.

She reaches out to mills offering bio-based nylon. She finds one producing a 76% bio-based nylon from castor oil, blended with a bio-based stretch fiber. No fluorinated finish. OEKO-TEX Standard 100 certified. Third-party tested for BPA, PFAS, phthalates, heavy metals, formaldehyde, and azo dyes.

The fabric costs 18% more per meter. But she eliminates the regulatory tail risk. She can make a credible hormone-safe claim. And she differentiates in a market where most brands are still using conventional petroleum synthetics with legacy finishes.

This is the inflection point for Sydney founders attending trade shows at ICC Sydney or sourcing through the Surry Hills fashion district, which is home to fashion showrooms, designer studios, and apparel wholesalers. The brands moving first will own the positioning.

What to actually spec: a founder's checklist

Certifications that matter

• OEKO-TEX Standard 100: Tests for over 1,000 harmful substances. Confirms garments are tested and certified free from over 1,000 harmful substances, including PFAS, BPAs, formaldehyde, and other endocrine disruptors.
• bluesign® approved: Covers input stream chemicals and production processes.
• GRS (Global Recycled Standard): For recycled content claims, but note the BPA risk in recycled polyester.
• ZDHC MRSL compliance: Manufacturing Restricted Substances List used by major brands.

Questions to ask your mill

1. What is the total organic fluorine content of this fabric? (Get the test certificate, not just a verbal claim.)
2. Is BPA used as a fiber coating or in any part of the production process?
3. What antimicrobial treatment, if any, is applied? (Avoid antimicrobial silver and triclosan.)
4. What finishing chemistry is used for stretch recovery, hand feel, or water repellency?
5. Can you provide third-party test results for phthalates, formaldehyde, and heavy metals?

Fabric architecture alternatives

Most conventional activewear uses petroleum-derived nylon or polyester with 10-20% elastane. The stretch comes from the elastane. The performance finishes, wicking, DWR, antimicrobial, get applied topically.

The alternative architecture:

• Bio-based nylon: Derived from castor oil, corn, or straw. Same polymer structure as conventional nylon 6,6, but from renewable feedstock. No inherent BPA.
• Bio-based stretch fiber: Alternatives to petroleum elastane are emerging. Some degrade faster. Some offer comparable recovery.
• High-recovery knit construction: Engineering the fabric structure for stretch and recovery rather than relying on elastane percentage. This reduces the synthetic load.
• No elastic waistbands or leg elastics: These are often where low-quality elastane with plasticizer load concentrates. High-recovery knit can replace them.

At Ohzehn, we built this architecture: 76% bio-based nylon, 24% bio-based stretch fiber, no PFAS, no antimicrobial silver, no fragrance infusion, third-party tested in U.S. labs. It took two years of mill work to get there. But the result is a fabric that performs without the chemical baggage.

The greenwashing trap: why "natural fiber" claims usually fall apart

Founders often think the solution is to go natural: cotton, bamboo, merino. The reality is more complicated.

Cotton lacks elastic recovery. To make cotton leggings that don't bag out after one wear, you need to blend with elastane. Now you have a synthetic component, and the finish chemistry to make cotton moisture-wicking introduces its own questions.

Bamboo is almost never actually bamboo fiber in apparel. Most "bamboo" activewear is chemically processed rayon via the viscose process. The finished fiber is regenerated cellulose, produced using carbon disulfide. The "natural" claim is marketing, not chemistry.

Merino is genuinely natural, temperature-regulating, and odor-resistant. But it has limited stretch, needs synthetic blending for activewear applications, and has shorter abrasion life than synthetics. It's also expensive and supply-constrained.

The honest answer is that performance activewear requires engineering. The question is whether that engineering uses legacy petroleum chemistry with endocrine-disrupting compounds, or whether it uses newer bio-based chemistries with cleaner profiles.

Reading a fabric label like a chemist

When you receive a fabric swatch or spec sheet, here's what to look for:

• Fiber content: "Polyester/Spandex" tells you the base. But it doesn't tell you about finishes.
• REACH compliance: Required for EU sales. Covers restricted substances.
• OEKO-TEX class: Class 1 is for infant products (most stringent). Class 2 is for direct skin contact. Activewear should be Class 2 at minimum.
• Finish information: Ask specifically. "Moisture-wicking" is a function, not a chemistry. What chemical achieves that function?
• Test certificates: Request actual lab reports, not just verbal or marketing claims.

"Fabric is not neutral. It is part of your biological environment."

The competitive positioning

More than 58% of consumers now favor multifunctional apparel suitable for both exercise and everyday wear, while around 41% actively seek sustainable and eco-friendly activewear options. But "sustainable" is vague. "Hormone-safe" is specific.

The brands that will win the next cycle aren't just making sustainability claims. They're making biological compatibility claims backed by third-party testing.

Consumers are more aware than ever of the risks associated with PFAS, and many are actively seeking out clothing made without these chemicals. This is demand waiting for supply.

For Sydney founders, the infrastructure exists. The mills are available. The testing labs are accessible. The regulatory pressure is providing the forcing function. The question is whether you move before the market shifts, or after your competitors do.

Biological awareness is the new standard. The old standard was aesthetic. Fit, color, hand feel. The new standard includes what's in the fiber architecture and what's applied to it. Mechanism, not marketing.

The founders who understand this will build the brands that earn trust in a market increasingly skeptical of greenwashing and increasingly aware of what they're putting against their skin for 16 hours a day.

Dougie Taylor

Co-Founder, Ohzehn Textiles · Building plastic-free performance apparel