Andrew Huberman· PhD
The sebaceous gland makes oily stuff, and the oily stuff is called sebum. ... The sebum does two things. First of all, it forms a little bit of a seal right at the place where the hair exits the skin. And that seal is very important, actually, for waterproofing of your skin. ... Now as I mentioned, sebum has two important properties. The other important property of sebum is that it actually is a strong antibacterial and antimicrobial.