A study of 39,622 men who had blood clots in their veins shows that those who took testosterone (for legitimate medical reasons or not) suffered increased risk for forming potentially-fatal blood clots (JAMA Internal Medicine, November 11, 2019). The risk for forming clots was highest in the first three months that they took it and men under 65 were at higher risk for clotting than older men. Venous clots, particularly in the deep veins and lungs, occur in more than one million North Americans each year (Circulation, 2019;139(10):e56-e528). Taking testosterone thickens blood and increases several clotting factors (including thromboxane) to increase clotting risk (Metabolism, 2014;63(8):989-994).
Other studies show that taking testosterone increases risk for clots in veins (BMJ, Nov 30, 2016), as early as three weeks after starting to take testosterone (Clinical and Applied Thrombosis/Hemostasis, Aug. 7, 2013). It also increases risk for strokes and heart attacks (Int J Endocrinol, 2015;2015:970750). Several studies show that taking testosterone gel for one year is associated with increased risk for forming plaques in arteries (JAMA, Feb 2017;317(7):708-716) and resultant heart attacks (PloS One, Jan 29, 2014). One study found that the relationship between testosterone and strokes is not established (Maturitas, 2017 Dec;106:31-37) and the literature is ambiguous whether taking testosterone increases risk for an enlarged prostate or prostate cancer (Ther Adv Drug Saf, 2014 Oct; 5(5): 190–200). The literature on testosterone treatment is very controversial, with some studies suggesting that testosterone treatment may increase risk for sleep apnea (BJU International, March 2018) and may worsen symptoms in men who suffer from that condition (World J Mens Health, Jan 2019;37(1):12–18).
Medically Indicated Uses of Testosterone
The generally recognized indication for taking testosterone is low production of that hormone by a man’s testicles resulting in lack of desire and ability to make love, weakened bones resulting in osteoporosis, or a feminine body shape with large hips and prominent breasts (J Sex Med, 2013;10(1):245-284). Abnormally low production of testosterone can be caused by genetic conditions, testicular damage from surgery, or infection and medications (J Investig Med, 2017;65(6):964-973). The normal range of blood testosterone in males is 300 to 1000 ng/dL, with an average level of 679 ng/dL. Male testosterone levels peak at age 20, and then slowly decline with aging. In 2014, the U.S Food and Drug Administration (FDA) warned that giving testosterone to men possibly increases risk for heart attack and strokes. However, many doctors still prescribe testosterone to men who do not have the conditions listed above (J Clin Endocrinol Metab, 2014;99(3):835-842).
Athletic and Vanity Uses of Testosterone and Anabolic Steroids
Bodybuilders and athletes in sports requiring great strength often take testosterone or its derivatives (such as anabolic steroids) to help them recover faster from workouts, which helps them grow larger and stronger muscles. Testosterone and its derivatives have many potential benefits for athletes and men who want to improve their physique and/or sexual performance. They increase bone density, muscle size and strength (with exercise), facial and body hair, red blood cell counts, sexual desire and sperm production; and decreases hip and breast fat. However, as shown in the studies cited above, these benefits are accompanied by serious, life-threatening risks. Anabolic steroids and testosterone are widely available without a prescription, and many men think that the benefits are more important than the risks. See my report below on the death of Dallas McCarver, and these articles:
Competitive Athletes and Doping
Rich Piana: Why Do So Many Bodybuilders Die Young?
Niam Suleymangolu, The Pocket Hercules
Why Did Ultimate Warrior Die at 54?
Aging and Low Testosterone
After age 40, testosterone levels decline by about one percent per year, associated with reduced muscle size and increased hip fat. If you suffer from a medical condition that is causing you to have low blood levels of testosterone, it may be reasonable to take testosterone in spite of the many serious side effects. However, taking testosterone just because you are suffering from aging makes no sense at all. I believe that the safest treatment for loss of testosterone associated with aging is to follow an anti-inflammatory lifestyle: exercise, lift weights, follow an anti-inflammatory diet, lose excess weight, and avoid alcohol and smoke.
Never Take Testosterone Pills or Anabolic Steroid Pills
We have known for more than 100 years that taking testosterone or its derivatives increases risk for serious and permanent liver damage (American J of Med, March 1950;8(3):325–331). When you take testosterone by mouth, it passes into the bloodstream that carries it directly into the liver where it can cause serious liver damage. However if you take testosterone by a skin gel or injection, it initially bypasses the liver and is far less likely to cause liver damage.
• Men with normal blood levels of testosterone (>250) should not take testosterone since it may increase risk for heart attacks, strokes, clots and liver damage, and can decrease their own natural production of testosterone.
• Older men with normal testicles and brain hormones should not take testosterone unless their own testosterone is very low (below 150) or their doctor gives them a reasonable explanation why they may need it, and they understand the risks of taking it.
• Most men who suffer from poor sexual function because they have conditions that damage their sexuality, such as excess weight, diabetes, arteriosclerosis or other life-shortening conditions that affect sexual function, should work to reverse those conditions rather than resorting to testosterone.
• Testosterone pills can damage the liver, so if a man chooses to take testosterone, the form of choice is a gel that is absorbed through the skin and does not go directly to the liver.