I’ve been hearing a lot of concerns lately about whether supplementing testosterone increases the risk of cardiovascular disease. Everyone should understand the risks & benefits before starting a medical treatment, so let’s look at what the evidence says.
Where The Rumor Started
Starting about 20 years ago, the popularity of testosterone replacement therapy exploded. Between 2000 and 2011, testosterone sales increased x 12, looking at data from 41 countries. Three studies were done between 2010-2014 that showed an increased risk of cardiovascular events (like heart attacks and stroke) with testosterone therapy. Not surprisingly, the FDA took note and slapped a black box warning on testosterone noting this so-called risk.
However, these three studies had major flaws in their design and required formal correction by the journals they were published in. The first study looked at men who had had a coronary angiogram, then gave some of them testosterone and others not. They found that the ones who got TRT had a slightly increased rate of heart attacks, stroke, and death from any cause. Well, guess what? If you’re getting a coronary angiogram, which is a test that looks for blocked heart arteries, you usually already have some pretty serious health issues already. That turned out to be the case in this study. Nearly all of the men who got TRT in this study had high blood pressure. About half of them had obstructed coronary arteries. Nearly 60% were obese. About 18% had congestive heart failure. See where I’m going with this? If you already have these health conditions, your risk of heart attack and stroke is already relatively high. It’s also important to note that in this study, it was within the statistical margin of error that there was no difference between the groups at all (in statistical terms, the confidence interval of the absolute risk difference between the groups crossed zero). That’s some pretty weak evidence that cardiovascular risk has anything to do with TRT.
The second study compared the incidence of non-fatal heart attack in men during the 90 days after they started TRT compared to a year-long period before they started TRT. They found that the risk of heart attack for men under the age of 55 actually went down after starting TRT. However, it went significantly up for men over the age of 75. Big surprise there. Men over the age of 75 have a relatively high risk of heart attack anyway. That doesn’t mean it had anything to do with TRT. For men in the study under the age of 65, only those who had pre-existing cardiovascular disease had a higher risk of heart attack. Once again, that’s reflective of their prior risk and does not show that it had anything to do with giving them testosterone.
The third study had similar flaws. It showed a higher incidence of cardiovascular events in the group that got TRT, but the average age of men in the study was 74, and most of them already had medical conditions like hypertension, diabetes, high cholesterol, and obesity. It also only included 209 men, and the total number of events was low anyway.
The Real Story
The truth is, many more studies have shown the benefit that testosterone replacement therapy has on men’s heart health, rather than the risk.
One example is a study done in 2017 that looked at 656 men who had low testosterone over the course of 10 years. One group received TRT and the other didn’t. The men who got TRT had only 2 deaths (non-cardiac) over the course of the study. The other group of men, who didn’t receive TRT, had 21 total deaths, 19 of which were due to cardiac events. The non-TRT group also had 30 nonfatal strokes and 25 nonfatal myocardial infarctions (heart attacks) over the 10 years. The men who did receive TRT had no strokes and no heart attacks. This came out to a 66-92% reduction in mortality for the men who received TRT compared to the ones who didn’t. It’s worth emphasizing that this was a long-term study that looked at outcomes over 10 years, showing the positive effects of TRT over time, unlike the short-term studies mentioned above.
Many other studies, like this one, have shown that optimizing men’s testosterone levels is associated with a lower risk of death from heart disease and from all causes. Another study from 2002 showed that of 504 men aged 67-75, the ones with higher levels of testosterone had lower levels of coronary artery disease. The higher the testosterone level, the less plaque the men had clogging their arteries.
More recently, in 2021, a meta-analysis looked at numerous studies from 2013 and on that looked at TRT and cardiovascular disease. The researchers found that when these studies were done well, they concluded that TRT was associated with better cardiovascular health.
TRT has also been shown to slow down the progression from metabolic syndrome (being overweight, having high cholesterol, high blood pressure, and/or high blood sugars) to diabetes or cardiovascular disease. Testosterone actually can lower blood pressure, get cholesterol back in check, and usually helps men lose weight and gain muscle.
What about other heart problems, like arrhythmias? Well, the evidence shows that TRT helps with that, too. A 2017 study, published in the Journal of the American Heart Association, tracked 639 men with low testosterone and divided them into 3 groups. Group 1 was given TRT to increase their testosterone to normal levels. Group 2 was given TRT but did not get their testosterone up to the normal range. Group 3 did not receive any TRT. The men whose testosterone levels were normalized (Group 1) had significantly lower risk of atrial fibrillation than the men who were given testosterone at a subtherapeutic dose (Group 2) or those who were given none at all (Group 3). There was no statistical difference between groups 2 and 3.
That said, there are always risks with any medical treatment. Some of the legit risks of TRT include the fact that it contributes to sodium and water retention, which can worsen severe heart failure, the risk of higher-than-normal levels of red blood cells/hematocrit, and an increase in blood clotting factors. However, no evidence actually suggests a significant association between testosterone treatment and an increased risk of blood clots for men without other predisposing factors.
I could cite much more evidence that shows the safety and health benefits of TRT, but I’m going to wrap it up for now. Bottom line is, there’s really no good evidence to date that shows that testosterone therapy increases the risk of heart disease. In fact, there’s a lot of good evidence that shows it contributes to heart health. Lots of different factors influence a man’s cardiovascular risk, or the lack thereof. Testosterone therapy can definitely be part of a healthy lifestyle, and can make creating a healthy lifestyle so much easier.