Hemp

Hemp is a bast fiber from the stalk of the Cannabis sativa plant, and the cleanest versions are separated mechanically, meaning the fiber is physically combed out without the harsh solvents or chlorine bleaching that conventional textile processing relies on.

The fiber itself sits well against skin. It is breathable and does not trap the chemical residues that irritate sensitive skin. Your real exposure comes later, from what gets added: azo dyes, which can release aromatic amines (cancer-linked breakdown chemicals) and trigger contact dermatitis, and formaldehyde-based resins used for wrinkle resistance, a known carcinogen that causes rashes on direct skin contact. The fiber being natural does not protect you. The finish does the damage, so a cheaply dyed hemp piece can carry the same load as any conventional fabric.

Look for OEKO-TEX STANDARD 100 certification, which caps formaldehyde at 75 ppm for direct-skin-contact garments and screens for restricted azo dyes, and favor mechanically processed, low-impact or natural-dyed hemp.

Hemp grows with little water and few pesticides and the undyed fiber biodegrades.