Andrew Huberman· PhD
Androgens such as testosterone and its derivatives, such as dihydrotestosterone, which will be much the topic of what we're getting into next, inhibit IGF-1 and cyclic AMP. Again, androgens such as dihydrotestosterone inhibit, prevent the action of IGF-1 and cyclic AMP, which you just learned a few moments ago, act to extend the anagen or growth phase of hair.