Andrew Huberman· PhD
The brakes on hair growth are going to be the things that either shorten the anagen phase or that extend the catagen phase or this quiescent phase, which is the telogen phase. The two major brakes on hair growth that we want to think about are PDE, which is a phosphodiesterase, anytime you hear -ase it's likely to be an enzyme, and TGF-beta-2.