Natural Versus Synthetic Fibers

Pick up your shirt right now and look at the tag. Chances are it says something like '100% Cotton' or '95% Polyester, 5% Spandex.' Those two words point to two totally different worlds: one fiber grew in a field, and the other was built in a chemistry lab from petroleum. Fashion designers choose between natural and synthetic fibers every single day, and that choice affects how clothes feel, how long they last, and even how they're recycled.

How to tell natural fibers from synthetic fibers by their source. Where five common fibers actually come from, including one made by an insect. Why designers pick one fiber over another for a specific garment. How to read a clothing label like a real textile expert.

Natural fibers come from plants and animals. Cotton grows as a fluffy boll on a cotton plant and has been spun into thread for over 7,000 years. Wool is sheared from sheep, usually once a year, without hurting the animal. Silk is spun by silkworms building their cocoons — a single cocoon can unravel into one continuous thread up to 900 meters long, longer than eight football fields. Synthetic fibers are manufactured from chemicals, most often petroleum. Nylon was the first, invented in 1935 by chemist Wallace Carothers at DuPont, and it was originally used for toothbrush bristles before becoming famous in stockings. Polyester followed in 1941, created by British chemists John Whinfield and James Dickson, and it's now the most-used fiber in the world.

Cotton breathes well and feels soft against skin, but it wrinkles easily and takes a long time to dry. Wool traps heat even when damp, which is why it's used in winter coats, but some people find it itchy. Polyester resists wrinkles, dries fast, and holds bright colors, but it doesn't breathe as well and can trap heat and odor. Spandex, invented in 1958, can stretch up to five times its original length and snap back, which is why it's blended into leggings and swimwear.

Your favorite jeans are woven from cotton denim. A fleece jacket is often made from polyester, sometimes even recycled plastic bottles — about 25 plastic bottles can be spun into one fleece jacket. A silk scarf traces back to a moth's cocoon. Leggings usually blend cotton or nylon with spandex so they stretch and hold their shape.