Let's get straight to it — here's what actually matters on this one.

• 100% organic cotton is the safest default — no synthetic fibers, minimal processing chemicals if certified (look for GOTS certification).
• Bamboo-derived fabric (bamboo viscose) is naturally soft and has some antibacterial properties, though processing methods vary in eco-friendliness.
• Avoid fabrics with heavy synthetic blending, spandex over 5%, and 'wrinkle-free' treated cotton, which often uses formaldehyde-based finishing resins.
• Wash new clothes before first wear — this removes surface chemical residue that's a common, overlooked trigger for skin reactions.

The fit-and-fabric-health takeaway: Choosing hypoallergenic fabric is really about minimizing two things: synthetic fiber content and chemical finishing — both are direct skin-contact factors.

Next up: check out our guide on how tight clothing affects circulation.