When Hans and Franz (Dana Carvey and Kevin Nealon) appear on "Saturday Night Live" reruns (and, more recently, in a cheeky commercial), they're all about fitness training. They want to "Pump ... you up!"

They know that's a great way to maximize testosterone levels. But what would they say about taking testosterone supplements?

The shady ones sold on the Internet (no prescription needed!) can have risky side effects, such as shrunken and soft testicles — or what Hans and Franz called "girlyman syndrome."

But even Food and Drug Administration-approved testosterone supplements now come with a warning: Taking testosterone ups the risk of heart attack and stroke in aging men.

That's launched a debate: to supplement or not to supplement.

A lot of guys say they feel much better (less lethargy, more sexual zip) when they take the hormone. In fact, men over 40 have tripled their use of these supplements in the past three decades.

But before you head to the doc and ask for the Big T, here's our tip: If you're overweight, lose it!

Extra fat, especially around your belly or abdomen, acts like a sponge, taking testosterone out of the blood, reducing libido, energy, and other male-related characteristics.

So, ditch the bad food, shoot for 10,000 steps a day, and build muscle with resistance training two or three times a week. Then ask your doc if supplements are for YOU.