Older men who have normal testosterone levels have been linked to a lower risk of stroke, heart attack and other heart related issues.

Since not all men have “normal” testosterone levels, many are on testosterone therapy. A long-term study on male veterans found that the men who underwent testosterone therapy to level off their testosterone had a much lower risk of heart problems than the men who had low levels, according to NYC Today.

Many previous studies have addressed whether or not testosterone therapy was effective or not. This new study answers those questions with a “yes,” it is important and useful. The FDA has put into place guidelines for medical experts around not over-prescribing testosterone drugs due to earlier studies that found a higher risk of stroke and heart attack. With the new study, there are now contradicting views on the matter.

The new study was conducted over 15 years, gathering and analyzing medical records for more than 83,000 male veterans divided into three groups. The first group consisted of veterans that had reached normal testosterone levels after therapy. The second group was men who were given testosterone therapy but their levels still remained below normal. And the third group of men did not receive any treatment and their levels also remained low.

After the participants received therapy, they were tracked for almost six years. The risk of death was 56 percent lower in the men that received testosterone therapy and their levels returned to normal and their risk of heart attack was also reduced by 24 percent and stroke risk by 36 percent.

Dr. Rajat Baru, a cardiologist at Kansas City Veterans Affairs Medical Center said, “It is the first study to demonstrate that significant benefit is observed only if the dose is adequate to normalize the total testosterone levels. Patients who failed to achieve the therapeutic range after testosterone replacement therapy did not see a reduction in (heart attack) or stroke and had significantly less benefit on mortality.”

Dr. Baru and the team said that they did not know exactly why testosterone benefited the overall condition of the heart.

“The mechanisms for these effects remain speculative,” they research paper said. Possible explanations, they say, could involve body fat, insulin sensitivity, lipids, blood platelets, inflammation, or other biological pathways.”