If your house is anything like mine, laundry baskets are constantly overflowing with synthetic activewear. With two teenagers active in sports, polyester shorts, compression shirts, and moisture-wicking jerseys are practically their daily uniform.

For a long time, I focused entirely on what went into my kids’ bodies. But as I began reading into textile manufacturing data, I realized that what covers their skin during intense, sweaty workouts is just as important. Specifically, I uncovered the widespread use of PFAS (per- and polyfluoroalkyl substances) in performance apparel.

I’m a working mom, not a textile engineer. But after looking at how these chemicals interact with human biology, I am actively changing how I shop for our sports gear. Here is the science behind why I’m stepping away from conventional moisture-wicking finishes and the swaps I am bringing into my kids’ gym bags.

🔬 The Science: What are PFAS Doing in Sports Gear?

PFAS are a class of thousands of synthetic chemicals valued for their ability to repel water, resist stains, and block oil. Because of these properties, clothing brands have heavily relied on them for decades to create “high-performance” athletic gear that keeps athletes dry and prevents sweat stains.

Dermal Absorption and Body Heat

The primary concern with athletic wear comes down to the environment in which it is worn. When my kids are running hard during games, their body heat rises, their pores dilate, and they sweat heavily.

Textile toxicology studies have shown that chemical finishes on synthetic fabrics can leach out under the friction of movement and sweat. Because PFAS bonds are incredibly strong, these “forever chemicals” do not easily break down. Instead, when they contact open pores, they can be absorbed through the skin. Public health data associates cumulative PFAS exposure with disrupted hormone pathways, metabolic shifts, and altered immune function—the exact opposite of what a growing athlete needs.

🕵️‍♂️ What to Look For: Navigating Performance Labels

Marketing for activewear can be incredibly slick. Here is how I look past the tag buzzwords to evaluate what my kids are wearing:

• “Stain-Resistant” or “Water-Repellent”: Unless explicitly stated otherwise, these finishes almost universally rely on a chemical coating containing PFAS.
• 100% Conventional Polyester: While polyester itself is a plastic fiber, cheap or ultra-processed synthetic garments are frequently treated with undisclosed anti-odor or chemical softening agents.

🏃 The Clean Apparel Swaps I’m Making

Phasing out toxic activewear doesn’t mean my kids have to play sports in heavy, uncomfortable clothes. I am transitioning our athletic drawer to safer, alternative fibers.

1. The Baselayer Swap: For compression shorts, sports bras, and practice tees that sit directly against their skin, I am prioritizing organic cotton blends or Tencel (lyocell). Tencel is derived from sustainably sourced wood pulp; it is naturally breathable and moisture-wicking without requiring a synthetic chemical finish.
2. The Heavy-Duty Training Swap: For winter training or outdoor practices, I am swapping out cheap synthetic fleece for Merino wool. Merino is a natural powerhouse—it regulates body temperature beautifully, wicks sweat naturally, and has inherent anti-odor properties that don’t rely on chemical additives.
3. The Certified Synthetic Swap: When team uniforms require standard synthetics, I look for items holding third-party certifications like OEKO-TEX Standard 100 or bluesign. These independent organizations test the final garment to ensure it is completely free from harmful levels of toxic substances, including PFAS and heavy metal dyes