I know more than a few balding men who'd make a deal with the devil if it meant getting their hair back.

Well, the devil is here... and he's ready to collect.

All he wants in exchange for those luxurious locks is your sex life--because new studies confirm what many men have already discovered the hard way: A common hair loss drug can lead to erectile dysfunction, impotence, and libido problems.

And that means men who think a full head of hair will boost their sex lives are in for the shock of their lives instead.

The med is finasteride, but you may know it better as the hair growth drug Propecia or the prostate med Proscar (that's right--different names... different conditions... same drug).

In one study, researchers interviewed 71 men between the ages of 21 and 46 years old who got slammed with sexual problems after taking the drug--despite the fact that none of them had any issues "down there" beforehand.

Some of them began having problems in the first month of taking the med.

Those problems covered just about everything a man has nightmares about: Researchers said 92 percent suffered from erectile dysfunction, 94 percent experienced low desire, 92 percent suffered a loss of arousal, and 69 percent had orgasm problems such as reduced ejaculation and semen volume, according to the study in the Journal of Sexual Medicine.

Ready for the worst part? The problems lingered long after the men stopped taking the med... and in some cases, they were still experiencing erectile dysfunction and other issues five or even 10 years later, with no sign of letting up.

A second study in the same journal, an analysis of side effects reported in other studies, confirmed the link.

Researchers behind that one say 8 percent of men who try the drug report erectile dysfunction, while 4.2 percent experience loss of libido--in both cases double the numbers of those who took a placebo.

That's actually the "good" news.

The bad news is that researchers say just about any man who takes the med can expect a certain amount of sexual problems since it works by blocking androgen, a hormone essential for sexual functions such as arousal, erection, and ejaculation.

Maybe it's time to look in the mirror and decide "bald is beautiful" after all--or least research one of the great nondrug alternatives that have helped men get their hair back without costing them their sex lives.