Acrylic vs Wool

The residual monomer is the concern: acrylonitrile is classified by IARC as Group 1, carcinogenic to humans, and the EPA treats it as a probable human carcinogen, with textile-plant workers showing raised lung and colon cancer risk after long exposure. Acrylonitrile can be absorbed through the skin, so warm, sweaty contact with a soft acrylic sweater or fleece is a real, if low-level, exposure route over time. Acrylic also sheds microplastics heavily, putting plastic fibers onto your skin and into the air at home, and like other synthetics it carries disperse dyes and finishing chemistry that can irritate sensitive skin.

The belief that a wool allergy is universal is wrong. A 2017 Acta Dermato-Venereologica review found wool is not a true cutaneous allergen; the itch is non-immune irritant contact dermatitis from coarse fibers (roughly 30-to-32 microns and up) mechanically jabbing your skin's nerve endings. So broad-grade wool itches more than fine merino purely because of fiber diameter. The chemistry matters more than the protein: superwash leaves chlorinated residues and a nylon-based Hercosett resin film, and the superwash step generates toxic adsorbable organic halides (AOX). Many wools are also moth-proofed with the insecticide permethrin, which is locked inside the fiber and can be OEKO-TEX certified, though it remains a pesticide on a garment. Residual lanolin in modern scoured wool is very low (under 0.5 percent) and rarely the real culprit. Wool itself breathes and thermoregulates well.