It's beginning to look like the initial hype was based on misinterpreted results.
Shit, did I say "beginning"? There was some indication of this a couple of years ago: https://www.thieme-c.../s-0033-1336630
Question is: Despite the fact that humans don't seem to produce functional Irisin, would it serve any role in humans? That is to say: Would exogenous administration prove beneficial?