A "precursor hormone" is a substance in our body that is transformed into a hormone. It acts as a building block for making hormones and helps to produce the required amount and types of hormones needed for various bodily functions. Full definition
This includes the master precursor hormones DHEA and pregnenolone as well as estrogen, progesterone and testosterone. (drjockers.com)
It is one of the most important precursor hormones and is converted into the more «potent» androgens, such as testosterone and estrogen. (holtorfmed.com)
DHEA, a testosterone and estrogen precursor hormone (don't worry, I'll explain that bit in a minute), is the most common hormone in your body. (tctmed.com)