Looking to be a more environmentally conscious shopper? You’ve probably heard about bamboo. Bamboo stands out for its ability to grow quickly with little or no need for pesticides, and it is used in a variety of products, from flooring to furniture. But when it comes to soft bamboo textiles, like shirts or sheets, there’s a catch: they’re actually rayon.

The Federal Trade Commission, the nation’s consumer protection agency, wants you to know that the soft “bamboo” fabrics on the market today are rayon. They are made using toxic chemicals in a process that releases pollutants into the air. Extracting bamboo fibers is expensive and time-consuming, and textiles made just from bamboo fiber don’t feel silky smooth.

There’s also no evidence that rayon made from bamboo retains the antimicrobial properties of the bamboo plant, as some sellers and manufacturers claim. Even when bamboo is the “plant source” used to create rayon, no traits of the original plant are left in the finished product.

Companies that claim a product is “bamboo” should have reliable evidence, like scientific tests and analyses, to show that it’s made of actual bamboo fiber.