Watch out, cotton: Tencel fibers are having a moment. If you’ve shopped for just about anything made of fabric lately – whether it’s clothing or bedding – chances are you’ve come across this fiber. You’ve probably also seen a bunch of claims tied to it, promising incredible softness and eco-friendly practices. As fiber scientists and product experts in the Good Housekeeping Institute Textiles Lab, we often have people ask us about the different types of materials they come across when they shop. So here’s the scoop on this trendy fiber you’re seeing everywhere: Tencel is a brand name for a set of fibers called lyocell and modal (think of it like Band-Aids are to bandages or Kleenex are to tissues). These fibers are known for feeling super soft and are widely used in sustainable fashion. Tencel is somewhat similar to rayon (i.e. viscose) because they’re what the industry refers to as “regenerated cellulose” fibers. Manufacturers take wood pulp, dissolve it in a chemical solvent, then push it through an extruder to form the fibers. The big difference is rayon requires more energy and chemicals to produce, which is both wasteful and toxic for the workers who make it. Tencel, on the...