The Edit
Low-Tox Activewear
Low-tox activewear starts with what the fabric actually is. Most activewear is polyester or nylon, which is plastic spun into thread. Estroni is built the other way around: 95% merino wool with 5% elastane for stretch, and no polyester or nylon anywhere in the fabric.
- 95% Merino Wool
- Zero Polyester
- OEKO-TEX Certified
- Non-Mulesed
01 Merino Sports Bra - Crossback · Indigo
Where you notice it first
A bra has the most skin contact and the least airflow of anything you own, which is exactly where polyester performs worst. Slim crossback straps, removable padding, and no chemical finish sitting against you for the length of a workout.
02 High Waist Full Merino Leggings · Indigo
High waisted, no plastic
A full-length legging is a lot of fabric against a lot of skin. This is 95% merino with 5% elastane for stretch, so what you have on all day is wool rather than spun plastic.
03 High Waisted Merino Short - 5" · Caviar
The warm weather default
Sits high, stays put, and breathes as the day heats up. Same fabric rules as everything else here, in the cut most people reach for from October onwards.
04 Merino Tank - Classic (V2) · Caviar
The layer you forget you are wearing
Light enough for a hot room, structured enough to wear on its own. It airs out between wears instead of holding onto the day.
05 Merino Straight Leg Leggings · Cocoa
Activewear that does not look like it
A straight leg in Cocoa that reads as trousers, so the low-tox decision follows you off the mat and through the rest of the day.
06 Merino Fitted Tee · Cocoa
A t-shirt that is actually wool
Most tees are cotton or polyester. This is ultra-fine merino, so it regulates temperature and resists odour, in the most ordinary shape we make.
07 Medium Impact Racerback Bra · Cocoa
More support, same fabric rules
A thicker underbust band and wide racerback straps for the sessions that need holding down, with no synthetic shell and no chemical anti-odour treatment.
08 Mid Waist 7/8 Merino Leggings · Caviar
The lighter legging
Mid waist, cropped at the ankle on most people, and less fabric than the full length. The one to start with if you have never worn wool to move in.
That one decision removes a lot at once. No plastic sitting against your skin while you sweat. No microplastics shedding into the wash. No chemical anti-odour finish, because merino resists odour on its own.
What low-tox means here, specifically
- 95% merino wool, 5% elastane. The elastane is what gives stretch and recovery. It is the only synthetic in the fabric, and we say so rather than rounding up to 100% natural.
- OEKO-TEX STANDARD 100 certified. Independently tested against more than 1,000 harmful substances, including pesticides, heavy metals, formaldehyde and restricted dyes.
- Responsible Wool Standard. Non-mulesed sheep, with a traceable chain of custody from farm to finished garment.
- No chemical odour treatment. Merino resists odour-causing bacteria through its own fibre structure, so nothing is added to imitate it.
- No microplastic shedding from the merino itself, because wool is a protein fibre rather than a plastic one.
Low-tox activewear, answered
Is Estroni activewear 100% natural fibre?
No, and we would rather be precise about it. The fabric is 95% merino wool and 5% elastane. The elastane is what makes activewear stretch and hold its shape. There is no polyester and no nylon.
Does polyester in activewear actually matter?
Polyester and nylon are plastics. They trap odour, hold heat and moisture against the skin, and shed microplastic fibres in the wash. Merino does none of those three things.
Is merino wool safe for sensitive skin?
The fabric is OEKO-TEX STANDARD 100 certified and knitted from ultra-fine merino, which flexes against skin rather than prickling. If you have a diagnosed wool allergy, merino is still wool, so it is not the right fabric for you. There is more detail in our sensitive skin edit.
What about the rest of my routine?
Our wellness range carries the same logic into a PVC-free cork yoga mat and plastic-free bamboo toothbrushes.