Men's Thermal Base Layer
Men's Cotton Long Johns & Thermal Base Layers
Thermal underwear is almost always polyester or a synthetic blend — man-made fibres worn tight against the skin for an entire winter's day. These are knit from 100% GOTS-certified organic cotton instead, with no natural rubber latex, no spandex, and no chemical finishes.
Made for men managing eczema, contact dermatitis, latex or elastic sensitivities, and chemical sensitivities — and for anyone who reacts to synthetic base layers but still needs the warmth.
Styles in this collection
- Long johns with fly — a full-length cotton thermal bottom with a functional fly opening.
- Long-sleeve base layer shirts — a cotton thermal top made to layer under a shirt or sweater.
Free from
- Natural rubber latex, rubber accelerators & spandex
- Formaldehyde & formaldehyde-releasing finishes
- Synthetic dyes and harsh chemical treatments
- PFAS and other “forever chemicals”
Trusted, tested, certified
- GOTS-certified organic cotton
- OEKO-TEX® Standard 100 thread
- MyMicrobiome textile-certified for skin-microbiome compatibility
- Sewn in our own GOTS- and B-Corp-certified factory
Layering for winter? Pair these with our men's cotton underwear and elastic-free cotton socks, or browse the full men's collection.
