Rayon is a semi-synthetic fiber made from regenerated cellulose (typically from wood pulp). It is made from trees, which are natural carbon sinks, meaning that when they are cut down, carbon is released into the atmosphere. Rayon is biodegradable and non-toxic, but the chemicals used in its production are super harmful to the environment. It has led to more deforestation, unfortunately, as many fast fashion brands have chosen to capitalize on it.