The Activewear Fabric Glossary: What Nylon, Spandex, and Merino Actually Do

Nylon

Strong, smooth, and quick-drying, nylon is a common base for leggings and jackets — it holds shape well over repeated wear and resists abrasion better than most synthetics, which is part of why it's frequently blended with spandex for training gear that needs to hold up to friction and stretch.

Polyester

Similar quick-drying properties to nylon, generally less expensive, and often used in moisture-wicking base layers and outerwear shells. It tends to hold onto odor more than nylon or merino wool over repeated wears, which is one reason odor-resistant treatments get added to polyester activewear specifically.

Spandex (elastane / Lycra)

Rarely used alone — spandex is the stretch component blended into nylon or polyester fabrics, typically making up somewhere between 5-20% of the blend. Higher spandex content generally means more stretch recovery (the fabric snapping back to shape) but can reduce breathability and durability slightly compared to lower-spandex blends.

Merino wool

A natural fiber, used mainly in socks and base layers rather than leggings or bras. It regulates temperature well in both heat and cold, resists odor-causing bacteria genuinely better than synthetics (not just marketing language — this is a real property of the fiber), and costs meaningfully more as a result.

Reading a blend on a tag

A listing that says "88% polyester, 12% spandex" is telling you the fabric leans toward durability and moisture-wicking with a moderate stretch component — useful shorthand once you know roughly what each percentage range tends to mean for feel and performance.