In November of 2013, a research study, carried out at a Veteran's Administration facility, appeared in the Journal of the American Medical Association. The conclusion:
“Among a cohort of men in the VA health care system who underwent coronary angiography and had a low serum testosterone level, the use of testosterone therapy was associated with increased risk of adverse outcomes” (Vigen, et. al.)
In other words, the use of supplemental testosterone appeared to be connected with heart attacks among the research subjects.