Can human growth hormone slow aging?

Word bolded for emphasis:

Why does Cecil apologize for his use of the word “stiff”? Is there some sort of innuendo I’m missing?

Stiff=corpse, it’s a pun - for which some people, inexplicably, feel a need to apologise.

It’s a more modest way of saying “ha ha, see my funny pun? Ha ha”.

Ohhh … now I perceive the word “cadaver” preceding the word “stiff.” I thought the pun was sexual in nature at first (although that didn’t make much sense, I didn’t really have much of an alternate explanation).