Ecdysteroids are a group of polyhydroxylated ketosteroids that are similar to androgens (e.g., testosterone). They were initially discovered in insects, where they are used during the molting process (when the exoskeleton is shed to allow for growth). Certain plants also contain ecdysteroids, where they play a role in protection from plant-eating insects. Ecdysteroids found in plants are called phytoecdysteroids, and those derived from animals are called zooecdysteroids.[1]
Phytoecdysteroids are more frequently used in supplements than zooecdysteroids, and sources include spinach, Cyanotis arachnoidea (a plant found in China), and Ajuga turkestanica (an Asian plant that lends its name to one of the most well-known ecdysteroid products, Turkesterone).[1][2] While ecdysteroids are a type of steroid hormone, they differ from human androgens in terms of their chemical structure, size, and polarity and therefore do not cause the hormone-related side effects that are associated with androgenic steroids.[3]