Tencel® is the brand name for lyocell, a fiber that is more absorbent compared to cotton, softer than silk, and cooler than linen. Key to using Tencel® next to skin are the natural anti-bacterial properties that come from the moisture being transported to the inside of the fiber which prevents a film of water from forming on the fiber.
Tencel® is a regenerated fiber, meaning that it's made from wood pulp that has been dissolved and made into a fiber. It's a cellulosic fiber like viscose, but uses a production process that is gentler on the environment. Tencel® requires less energy and water, no chlorine is used and the waste products are minimal and considered harmless.
When a product made of Tencel® has reached the end of its life length, it can be recycled and is also biodegradable since it's made from cellulosic fiber.