Bamboo vs Cotton

Do not let the eco and natural marketing fool you. The FTC has fined retailers including Kohl's and Walmart, and warned dozens more, for labeling rayon as bamboo and claiming false environmental benefits, because the rayon process uses toxic chemicals and emits hazardous pollutants. By law it must be called rayon (or viscose) made from bamboo. For your health the story is identical to viscose: carbon disulfide is the worker hazard, and residual processing chemicals, dyes, and any formaldehyde finishes can leave residue that irritates skin or triggers contact dermatitis. The plant itself adds no special skin benefit once it is dissolved into rayon.

Most field pesticide residue degrades or washes out during processing, so it is the finishing chemistry on the finished garment you wear that matters most. Conventional cotton labeled wrinkle-free, easy care, or no-iron is frequently treated with formaldehyde-based durable-press resins, a recognized human carcinogen that off-gasses and is linked to contact dermatitis and skin irritation. Reactive and azo dyes can also leave residue that touches your skin all day. The upside: untreated cotton is genuinely breathable and lets air move against your skin, which is why it stays comfortable in heat.