Every layer, tested & certified
Below is every layer of fabric that touches your body, what it's made of, and the certificates that back it up.
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OEKO-TEX Standard 100
Global Organic Textile Standard 6.0
OEKO-TEX Standard 100
Global Organic Textile Standard 6.0
The layers, explained
1
Inner lining
95% organic cotton, 5% spandex.
Soft, breathable, and kind to your skin, our organic cotton lining keeps you comfortable all day.
2
Outer fabric
95% bamboo viscose, 5% spandex.
Made from fast-growing bamboo, processed into a soft, moisture-wicking fabric that keeps you feeling fresh.
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3
Inner core (the leak-proof layer)
80% polyester, 20% breathable PUL.
This is the layer that does the heavy lifting on leak protection. We use breathable PUL rather than rubber.
4
Plant-based water repellant finish
This plant-based treatment is free of PFAS ("forever chemicals") and other fluorocarbons — it's also bluesign®-approved and an approved additive under GOTS 4.0, so it meets a genuinely high bar on chemical safety, not just a marketing one.
Organic cotton, honestly
The lining that sits against your skin is 95% organic cotton, GOTS 6.0 certified. GOTS is the strictest organic textile standard out there, covering both the organic status of the fibre and restrictions on the chemicals used to process it.
Bamboo, honestly
Bamboo is a genuinely great crop - it grows fast, needs very little water, and doesn't need pesticides to thrive. But turning bamboo into soft fabric is a chemical process, the same as it is for rayon from any plant. Our outer fabric is bamboo viscose: bamboo pulp that's dissolved, filtered and spun into fibre.
We chose bamboo for its breathability and softness. Our supplier recovers and reuses the solvent used in this process rather than releasing it, which keeps the environmental footprint down.
What OEKO-TEX Standard 100 means
Our manufacturer is OEKO-TEX Standard 100 certified. In plain terms: Fri Period underwear has been independently tested and confirmed free of harmful levels of things like certain dyes, formaldehyde and heavy metals.
The leak-proof layer - no PFAS
The layer that actually stops leaks is a breathable PUL barrier finished with a PFAS-free water-repellent treatment. No PFAS or other fluorocarbons are used (these "forever chemicals" are increasingly found in waterproof and stain-resistant products, and don't break down in the environment or the body).
We chose this finish specifically to get leakproof performance without those chemicals.
What we're still working on
We'd rather tell you where we're at than pretend we've solved everything. Right now, we're working toward confirming a closed-loop process with our bamboo supplier as well as end-of-life recycling options. We'll update this page as that changes.
Frequently Asked Questions
Bamboo the plant is genuinely low-impact — fast-growing, low water, no pesticides. Turning it into fabric (bamboo viscose) is a chemical process, same as any rayon. We're upfront about that trade-off above.
Human/skin safety only - not sustainability or labour conditions. You can read about our approach to that here.
No - the leakproof layer uses PUL, a plastic laminate, which is standard across the category for leak protection. We've chosen a PFAS-free, bluesign®-approved finish specifically to avoid harmful chemicals often used in waterproofing.
