Merino Short - 5"
Designed for everyday movement in merino.
Shop nowBPA in Sports Bras & Leggings: The Hidden Chemical Risk in Your Gym Bag
For years, the conversation around "toxic chemicals" in our homes was limited to plastic water bottles and Tupperware. We learned to look for "BPA-Free" stickers on our lunchboxes, but we never thought to look for them on our leggings. That changed recently when the Center for Environmental Health (CEH) sent legal notices to major activewear brands after finding high levels of Bisphenol A (BPA) in polyester-based sports bras and leggings—in some cases, up to 40 times the legal limit under California’s Prop 65.
If you have ever wondered, is there BPA in polyester? or searched for a toxic workout clothes list 2026, you aren't alone. As more athletes and movement enthusiasts realize that their skin is their largest organ, the demand for BPA free leggings and non-toxic gear has moved from the fringe to the mainstream.
What Exactly is BPA and Why is it in My Sports Bra?
Bisphenol A (BPA) is a chemical compound primarily used to make polycarbonate plastics and epoxy resins. However, in the textile industry, it serves a different purpose. Unlike "Forever Chemicals" (PFAS) which are usually added for water repellency, BPA is often a byproduct of the manufacturing process or added intentionally for specific technical reasons:
- Dye Fixation: BPA is used to help synthetic dyes "stick" to polyester and nylon fibres, ensuring your neon leggings stay bright after multiple washes.
- Anti-Static Properties: It can be used as an intermediate chemical to reduce the "cling" common in synthetic fabrics.
- Flame Retardancy: In some cases, BPA-based chemicals are used to meet textile safety standards.
While many brands are moving toward being BPA free, the reality is that the global supply chain for synthetic fabrics is incredibly complex. For a deeper dive into the broader chemical landscape of your gym bag, you may want to read: Are My Gym Clothes Messing With My Hormones?
The Sweat Factor: Why BPA in Activewear is a Unique Risk
The presence of BPA in a plastic bottle is one thing; the presence of BPA in sports bras is another. When you exercise, three things happen that increase your risk of chemical absorption:
- Heat: Body temperature rises, which can cause chemicals to "leach" or migrate out of the synthetic fibres.
- Sweat: Moisture acts as a solvent, pulling chemicals from the fabric onto the skin.
- Friction: The constant rubbing of a sports bra or leggings against the skin during movement can break down the fabric surface, making it easier for chemicals to be absorbed dermally.
Because sports bras and leggings are "base layers"—worn directly against the skin for hours at a time—the exposure is prolonged and intimate. This is why many are now seeking BPA free leggings made from natural fibres that don't require heavy chemical processing for dye fixation.
Data Comparison: Synthetics vs. Natural Merino Blends
When comparing your options, it's important to understand how different materials handle chemical additives. Here is how standard polyester compares to the natural performance of Merino wool.
| Feature | Synthetic (Polyester/Nylon) | Estroni Merino Blend (95/5) |
|---|---|---|
| BPA Risk | High (Used in dye fixation/production) | Naturally BPA-Free |
| Hormone Disruptors | Potential for BPA and PFAS | Low-Tox / Natural Fibres |
| Dye Requirements | Requires heavy chemical fixatives | Takes natural dyes easily |
| Static Control | Chemical anti-static treatments | Naturally anti-static |
| Skin Interaction | Can cause irritation/clogged pores | Hypoallergenic and breathable |
While some wonder Do Workout Clothes Have PFAS?, the BPA issue is distinct because it is often tied to the very structure of how synthetic clothes are dyed and finished.
How to Spot "Red Flags" (Your Toxic Workout Clothes List 2026)
As we head toward 2026, transparency in the textile industry is increasing, but it is still difficult to find an "ingredient list" on your clothing. To avoid BPA in activewear, look for these indicators:
- Avoid "100% Polyester" Base Layers: High-polyester blends, especially those with "shiny" finishes, are the most common culprits in CEH testing.
- Smell the Fabric: If a new garment has a strong, pungent chemical odour out of the bag, it may be off-gassing. See our guide on Why Do New Workout Tanks Sometimes Smell Like Chemicals? for more details.
- Choose Certified Natural Fibers: Look for Oeko-Tex or GOTS certifications, which test for harmful substances including BPA.
- Prioritize Merino Wool: Unlike synthetics, Merino wool is a protein-based fibre that doesn't require the same chemical fixatives to hold colour or manage moisture.
The Natural Alternative: Why Merino is Inherently BPA-Free
At Estroni, our mission is to provide an alternative to the "plastic" activewear industry. Because Merino wool is a natural fibre, it doesn't require the chemical "workarounds" that polyester does. It is naturally anti-static, naturally odor-resistant, and manages moisture through its porous core rather than through chemical coatings.
We use a 95% Merino and 5% Elastane blend. While we strive for "plastic-free," we’ve found that a tiny hint of elastane is essential for the durability and "snap-back" required for leggings and sports bras. You can learn more about this philosophy in our article: 100% Merino vs 95/5 Blends: Which Is Better for Activewear?
Final Thoughts
The discovery of BPA in sports bras is a wake-up call for the fitness industry. We spend so much time focusing on the "purity" of what we eat and drink, yet we spend our most intensive, sweaty hours wrapped in synthetic plastics. By choosing BPA free leggings and natural-fibre tops, you aren't just making a choice for the planet—you're making a choice for your long-term hormone health and skin integrity.
