We hate to say it, but low testosterone levels can have a slew of negative effects for older guys.

But even now there's a scientific tug-of-war over testosterone-replacement therapy. Sure, it sounds great—what guy doesn't want more of the "masculine hormone"?—but risks of testosterone therapy can include the growth of pre-existing cancerous cells, testicular shrinkage, infertility, even heart attack or stroke, as one of our writers discovered.

The positives are just as extreme. Aside from increased strength and motivation, men can enjoy greater urinary health, better sexual function, and a higher quality of life, according to new research from Boston University Medical Center.

In the study, published in the Journal of Urology, researchers enrolled roughly 650 men in their 50s and 60s. Some of the men had unexplained testosterone deficiencies, while others suffered from genetic hypogonadism (when gonads fail to produce testosterone). About 360 men received testosterone therapy for eight years (the remaining didn't).

What's more, the men who underwent testosterone therapy enjoyed a significant bump in their urinary and sexual function (lower instance of erectile dysfunction, higher sex drive), as well as better quality of life (sunnier mood, higher confidence).

Another interesting detail: Two men in the treatment group died from causes unrelated to cardiovascular failure, while 21 in the non-treatment group died (19 deaths were cardiovascular-related). Those mortality rates suggested that testosterone therapy isn't necessarily linked to a greater instance of heart attack or stroke, the researchers suggested.

"It is thought that testosterone treatment in men may increase prostate size and worsen lower urinary tract symptoms," study author Abdulmaged Traish, Ph.D., said in a press release. Researchers discovered some men had larger prostates post-testosterone therapy, but they experienced fewer instances of frequent urination, incomplete bladder emptying, and waking at night to urinate.

"[Testosterone therapy] is well-tolerated with progressive and sustained improvement in urinary and sexual function, and overall improvement in quality of life," Traish added.

Something to think about if your testosterone takes a hit one day and you want to fight manopause head-on.