A newly released study suggests that prolonged treatment may be the key to reducing the serious health risks commonly associated with testosterone replacement therapy.

The controversial treatment is aimed at increasing testosterone levels among men who are lacking the hormone. The supplements can be administered as skin patches, gels, implants or injections.

But the safety of hormone replacement therapy has come into question in recent years, with several studies suggesting sudden spikes in testosterone levels may increase the risk of heart attack, stroke and prostate cancer.

In March of 2015, the U.S. Food and Drug Administration (FDA) agency placed heart attack and stroke warning label warnings on testosterone supplements.

But the new study, authored by Dr. Robert Nam at the Sunnybrook Health Sciences Centre in Toronto, suggests the length of the treatment -- and not the drugs themselves -- may be the key to making it safe.

Nam’s study followed 38,000 men with low testosterone. It found that those who had got the lowest doses of the hormone showed higher rates of heart attacks and strokes in their first two to three months of treatment. The therapy, however, had the opposite effect on those who continued to receive the treatment for three to five years.

“Men on it for at least five years have that protective effect, so it is important to take it for a long time,” Nam said.

The study could help men who would benefit from testosterone replacement by abating some of their worries about the controversial treatment.

And men like Stephen – a patient who says his hormone deficiency was making him sluggish -- have seen the benefits of the treatment first-hand.

“More men will feel better,” he said. “It’s not going to make you superman, but it sure helps.”

Nam said the study will help doctors determine whether testosterone replacement therapy is appropriate for their patients.

It also emphasizes the need to closely monitor patients who have just started the treatment.

But the findings may also compromise a number of class-action lawsuits launched throughout Canada and the United States by men who claim they’re been harmed by the treatment.

But lawyer Jill S. McCartney said: “There's constantly more questions being answered, more research to be done,” she said. “It's a moving target."

Low testosterone affects about 20 per cent of men over the age of 60 and about half of men over 80.

The study was conducted by a group of physicians from Ontario healthcare facilities, including Sunnybrook Health Sciences Centre and Mount Sinai Hospital, and highlighted at a American Urological Association meeting in San Diego. The study was funded by the Physicians' Services Incorporated Foundation and Ajmera Family Chair in Urologic Oncology.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip