According to new research published Wednesday in the Journal of Clinical Endocrinology & Metabolism, a timely dose of testosterone may indeed be able to help rejuvenate certain older men’s waning sex lives.

Testosterone therapy has become a popular treatment for men of all ages, but especially among those who are older, to help manage a variety of health problems, especially those related to sex. But many critics have questioned the value of these treatments, pointing to a lack of definite evidence. To settle the debate, the National Institutes of Health sponsored a far-reaching series of seven placebo-controlled clinical studies across 12 cities that enrolled nearly 800 men over the age of 65 — the pithily named Testosterone Trials.

Completed in 2013, the first results from the trials were published earlier this February. The researchers found there were some modest health benefits, with men on testosterone becoming happier and more sexually and physically active. The current study explores more deeply the trial that focused on sexual function. It enrolled 470 men who complained of a low libido, had low testosterone levels, and had a regular sexual partner.

The results showed that those given testosterone in a topical gel experienced noticeable improvements in sexual function compared to those given a placebo. Importantly, these improvements lasted for the entire year they were studied and higher testosterone levels predicted better signs of health, both findings that further indicate the gel had a direct effect on the men.

"For symptomatic older men with low testosterone levels, testosterone therapy led to consistent improvement in most types of sexual activity," lead author Dr. Glenn Cunningham of the Baylor College of Medicine and Baylor St. Luke's Medical Center in Houston, Texas, said in a statement.

Cunningham and his team measured sexual function in 12 different ways, and the treatment group improved in all but two. They looked forward to sex, masturbated, and even flirted more often than those in the placebo group. Sadly, no matter how much extra juice they got into their system, other people didn’t flirt with them any more than usual.

Intriguing as these findings are, they shouldn’t be seen as miraculous. Referencing research from another of the trials, the authors noted that a testosterone boost didn’t improve the sexual appetite or function of men who had lower, but still normal levels of the hormone. And when it came to erectile function, testosterone wasn’t as effective as more conventional drugs like Viagra. All in all, it seems testosterone therapy can be a useful treatment for men whose sex drive has taken a sharp dive because of their flagging testosterone levels, but it’s probably not gonna turn anyone else into the next casanova.

"Our findings indicate low testosterone is one cause contributing to reduced libido and erectile dysfunction in older men," said Cunningham. "Men experiencing these symptoms should be evaluated for testosterone deficiency."

Source: Cunningham G, Stephens-Shields A, Rosen R, et al. Testosterone Treatment and Sexual Function in Older Men with Low Testosterone Levels. Journal of Clinical Endocrinology & Metabolism . 2016.