Regenerated fibres are made from natural cellulose (wood pulp, bamboo) processed through chemical dissolution and re-extrusion. Key types: viscose (rayon), modal, lyocell (Tencel), cupro. They combine the drape and breathability of natural fibres with the processability of synthetics. Lyocell's closed-loop solvent process earns a sustainability score of 1. Viscose and cupro score 2 due to open-loop processes and chemical use.