Hormone Health & Your Activewear: The Plastic Connection

You track your cycle, prioritize sleep, and choose organic whole foods. But have you looked at the label on your leggings?

In 2026, the wellness conversation has shifted from "calories in" to "toxic load." While we focus on the food we eat and the products we put on our face, we often overlook our largest organ: our skin. Specifically, how our skin interacts with synthetic activewear during our most vulnerable moments—when we are sweating.

Estroni’s Merino-first philosophy isn't just about comfort; it’s about biological safety.

The "Trojan Horse" Effect: Sweat and Plastic

Most activewear is made from petroleum-based polyester or nylon. These aren't just fabrics; they are plastics. To make them perform like clothing, they are often treated with bisphenols (BPA/BPS), phthalates, and PFAS (Forever Chemicals).

The Data: A 2024 study by the University of Birmingham found that human skin can absorb up to 8% of toxic chemicals (like flame retardants and plasticizers) from microplastics when the skin is moistened by sweat.

The study refers to this as the "Trojan Horse" effect: your sweat acts as a solvent, leaching these endocrine-disrupting chemicals out of the plastic fibers and carrying them directly into your bloodstream.

Merino: The Bio-Safe Alternative

Unlike synthetics, Merino wool is a natural protein fiber. It doesn't require the chemical "cocktails" that plastics need to manage odor or moisture. By choosing a natural fiber base, you are actively reducing your daily chemical exposure.

No BPA/BPS: Merino does not require plasticizers to remain flexible.
Natural Odor Control: While synthetics use Silver-Ion coatings (which can disrupt skin microbiomes) to fight smell, Merino is naturally bacteriostatic.
Hypoallergenic: Superfine Merino (under 18.5 microns) is clinically proven to be beneficial for sensitive skin, unlike disperse dyes used on polyester which are known irritants.

Endocrine Disruptors & Performance

Why does "Hormone-Safe" matter for your workout? Endocrine Disrupting Chemicals (EDCs) mimic or interfere with the body's hormones. For women, this can impact:

Metabolic rate and weight management.
Thyroid function and energy levels.
Menstrual cycle regularity and reproductive health.

The Verdict: If you are working out to balance your hormones or manage stress (cortisol), wearing plastic that leaches EDCs into your system during your peak sweat state is counterproductive.

Comparison: The Health Audit

Feature	Estroni Merino	Standard Synthetic Gear
Material Source	Natural Protein (Bio-based)	Petroleum (Plastic-based)
Endocrine Safety	High (No BPA/PFAS/Phthalates)	Risk (BPA often detected in lab tests)
Chemical Leaching	Zero (Natural fiber)	Up to 8% absorption via sweat
Skin Barrier Impact	Therapeutic (Maintains pH)	Irritant (Disperse dyes & coatings)