Men should not take the male hormone, testosterone, unless their testicles are not producing adequate amounts. A study of 172,000 men found that those who have the genes for high blood levels of testosterone are at a 37 percent increased risk for suffering a heart attack, eight times the risk for heart failure and double the risk for blood clots in the brain and lungs (British Medical Journal, March 6, 2019). Many other studies show that weight lifters and other men who take large doses of testosterone (when their own testosterone levels are normal) are at increased risk for suffering heart attacks. Recreational weight lifters who take anabolic steroids and other hormones that mimic testosterone can suffer from significant heart damage (left ventricles) even many years after they stop taking these drugs (Circulation, May 23, 2017). Testosterone can increase risk for forming the blood clots that cause a heart attack. The U.S. Food and Drug Administration requires testosterone labels to list the increased risk of heart attack and stroke, and the Endocrine Society recommends that testosterone be given only to men who:
• have proven low levels of testosterone,
• have not had a heart attack or stroke in the last six months, and
• are at very low risk for prostate cancer (The Journal of Clinical Endocrinology and Metabolism, March 2017).
In spite of these very real concerns, global sales of testosterone have increased 12-fold in the last 20 years.
Testosterone Gel Did Not Improve Memory
In the Testosterone Trials from the University of Pennsylvania(TTrials), 788 men over 65 years of age who had low levels of testosterone (<275 ng/dl) were given either testosterone gel or placebo for one year. In 493 of these men who had age-associated memory impairment, the treatment with testosterone was not associated with improved memory or other cognitive functions such as verbal memory, visual memory, executive function, or spatial ability (JAMA, 2017;317(7):717-727).
Mixed Results on Heart Attack Risk
The TTrial cardiovascular study results showed that taking testosterone significantly increased plaque in the arteries leading to the heart, to increase risk for heart attacks (JAMA, 2017;317(7):708-716). On the other hand, another study of more than 44,000 men with low testosterone showed that three years of testosterone gel reduced heart attack rate 25 percent compared to those given placebos (JAMA Internal Medicine, Feb 21, 2017).
• Men with normal blood levels of testosterone (>300 ng/dl) should not take testosterone as it can increase risk for heart attacks, clots, and liver and lung damage. It can also shut down their own natural production of testosterone to make them sterile.
• Older men should not take testosterone unless their testosterone is very low (at least below 150 ng/dl), meaning that their brain hormones or testicles are damaged so they cannot make adequate amounts of testosterone.
• Most older men who suffer from poor sexual function have conditions that cause the damage, such as excess weight, diabetes, arteriosclerosis or other life-shortening conditions. Testosterone is not a solution for these conditions. These men can often correct their sexual dysfunction and prolong their lives by changing the lifestyle habits that caused their problems.
• Almost never should men take testosterone pills because they can damage the liver. If they do choose to take testosterone, the form of choice is a gel that is rubbed on and absorbed through the skin, so it is not absorbed from the intestines and passed immediately to the liver.