By Tobias Carroll The issue of declining testosterone levels is something that’s concerned many men over a certain age. That may well be compounded for those men who are frequent television viewers and see ads with former professional athletes touting certain supplements. And if you’ve read all of this and thought that this sounds like a target ripe for satire, you’d be spot-on. This weekend’s Saturday Night Live featured a sketch parodying a Nugenix commercial — in this case featuring Frank Thomas (Kenan Thompson) and Doug Flutie (Kyle Mooney) sharing some advice with a man somewhat concerned…