clean running gear. not plastic. not toxic.
notnotrunning makes women's 100% merino wool running shorts — non-toxic running shorts with no polyester, no microplastics, and no PFAS.
Women's 100% merino wool running shorts. First release — coming soon
Certified clean
every fibre, certified.
One fibre, nothing else — 100% RWS-certified Australian merino, tested to OEKO-TEX Standard 100.
rws australian merino
The merino we use is Australian, certified to the Responsible Wool Standard — for sheep welfare, responsible land management, and chain-of-custody from grower to yarn.
oeko-tex standard 100
The merino yarn is tested to OEKO-TEX Standard 100 — free from harmful substances. No PFAS, no formaldehyde, no heavy metals, no banned azo dyes.
Why no polyester
running was supposed to be healthy.the gear shouldn't undo that.
Most performance shorts on the market are polyester, nylon, or elastane — petroleum-derived plastics spun into fibres.
Every wash cycle releases up to 700,000 microplastic fibres into waterways — and a similar order of magnitude is released straight into the air around you during a run. They've now been detected in human blood, lungs, the placenta, and breast milk.
Sweat, heat, and friction during a run pull residual industrial chemicals — antimony from PET production, PFAS “forever chemicals”, phthalate softeners — directly through the skin. These compounds are associated with endocrine disruption, inflammation, reduced fertility, and elevated cancer risk in a growing body of peer-reviewed research.
Merino is the opposite. A living fibre, grown on a sheep, that regulates temperature, wicks moisture, resists odour without antimicrobial coatings, and biodegrades fully at end of life. No plastic in. No plastic out. We weighed it against lyocell, the other natural fibre on our shortlist, before deciding — that comparison is in the research.
Every claim here is drawn from peer-reviewed studies. We've laid out the science — sources, citations, and the things we deliberately don't claim — on our research page. New here? See how merino compares to synthetic running shorts or read the FAQ.
Our north star
notnotrunning exists to prove that activewear doesn't have to be disposable, doesn't have to be plastic, and doesn't have to be sold by making women feel like they're not enough.
Almost all running gear is synthetic, made from polyester, nylon and elastane. It's cheap to make, it's marketed hard, and it's designed to be replaced: a new colour, a new season, a new reason to buy the same shorts again. We think that model is broken at both ends. It's wasteful for the people who buy it, and plastic sits on your skin with every kilometre you run.
That last part matters more than the industry lets on. What synthetic fabrics shed, and what it may be doing to us, is still being studied, and there isn't a definitive verdict yet. But we don't think “wear plastic and hope for the best” is good enough when a natural alternative exists.
So we make the opposite of disposable. Women's running pieces in natural fibres, built to last rather than built to be repurchased, designed to be worn, washed, and kept, not churned through. Merino is temperature-regulating, breathable, and resists odour without chemical treatment, which means fewer washes and a longer life. And it simply feels better against your skin than the synthetics it replaces, with no need to hope there isn't a negative impact on your health.
We also want to change how this industry speaks to women. Too much of it runs on insecurity. The quiet, constant message that you need to shrink, tighten, fix, or fit in before you belong. That you're one purchase away from finally being enough. We think that's both dishonest and exhausting, and we refuse to build a brand on it. No airbrushed impossible standard, no pressure, no manufactured urgency. Just well-made clothing that respects your body and your intelligence, and gets out of the way so you can focus on your run.
This is also why we operate the way we do. We sell directly, so the price reflects the garment and not a chain of markups.
And we'll always tell you what we don't claim as clearly as what we do. We're not plastic-free, as some finishing treatments might still involve synthetic components, including the thread, and we'd rather say so than pretend otherwise. We're not going to promise merino will change your health. What we will promise, though, is honesty about the trade-offs, gear that's genuinely made to last, and a straight answer every time you ask us a question.
Clothing you can trust, from a brand that's willing to be honest about what it is.