An animal study, appearing in the journal, Circulation, (2007; 116(21): 2427-34) indicates that physiologic testosterone injections may decrease arterial plaquing. The study involved 33 feminized mice (mice with a nonfunctional androgen receptor and low circulating levels of testosterone). It was found that physiologic doses of testosterone increased HDL production and reduced fatty streak formation on arterial walls. Testosterone injections given to men with low testosterone in a study published in Atherosclerosis (1996;121:35-43), and they were found to help lower total cholesterol and LDS cholesterol. Interestingly, the injections did not affect HDL levels. HDL levels were lowered with testosterone injections, according to research appearing in the International Journal of Andrology (1995;18:237-242), but the volunteers were healthy, and had normal testosterone levels.
Other research appearing in Hypertension Research (2007 Nov;30:1029-34) looked at testosterone levels in 187 men and compared the hormone levels to the health of the vascular endothelium (lining). Elasticity of the blood vessel lining was evaluated using ultrasound. Low testosterone levels correlated with poor vessel elasticity, and the association held true regardless of age, blood pressure, weight, cholesterol levels or other cardiac risk factors.
Testosterone seems to benefit men with heart failure. A double-blind, placebo controlled study appearing in the European Heart Journal (2006; 27(1): 57-64) looked at the relationship between testosterone and heart failure. In the year long, double-blind, placebo controlled study, 76 men with moderate to severe heart failure were randomized to receive either a testosterone patch or a placebo. At the end of the 12 months, 35% of the subjects receiving the testosterone improved by one NYHA class. Overall, the testosterone improved the ability to exercise and quality of life. Another double-blind, placebo controlled study appearing in Heart (2004;90:446-447), found that testosterone injections improved walking distance in congestive heart failure patients.