Testosterone and Heart Health in Men: How Testosterone Replacement Can Lower Your Risk of Heart Disease

As humans go through life, we experience many changes within our minds and physical bodies. One of the major changes that women go through is menopause, and it’s caused by a natural decline of hormones in the body that are responsible for reproduction. Something similar can happen in men. If a man’s testosterone levels decrease below a certain level they can be diagnosed with something called male hypogonadism.

Similar to hormone replacement therapy (HRT) in women, HRT in men has had a controversial past regarding its risks and safety when it comes to something called cardiovascular disease (CVD). The most common types of CVD include heart attacks and strokes, but it includes any type of disease that affects the heart and blood vessels in the body.  

A lot of research has been done to study the relationship between testosterone replacement and CVD. While the majority of research has shown that replacing testosterone in men can decrease the risk of CVD and death, a small amount of studies between 2010 and 2013 suggested otherwise. 

Similar to early studies on HRT in women, which I discussed last month, these results on testosterone replacement sparked concern within the medical community. In 2015, the FDA responded to this concern by requiring manufacturers to conduct additional research on the safety of testosterone replacement. 

This past summer, this research was published, and the results have changed everything. 

What is Testosterone Replacement Therapy?

Testosterone is the main sex hormone in men, and it’s responsible for growth of the male reproductive system and many of the physical characteristics in men such as body hair, muscle mass, and voice depth.¹

In addition to being responsible for the male reproductive system and male characteristics, testosterone also affects parts of the body like the heart, blood vessels, brain, and kidneys.

As men age, their levels of testosterone naturally decrease. Testosterone levels are at their highest around 30 years old, and from there they decrease by about 1%-2% each year.¹

Male hypogonadism is diagnosed by checking levels of testosterone in the blood when you first wake up. Healthy levels of morning testosterone in men are 300-1000 ng/dL. So if testosterone levels are less than 300 ng/dL in the morning, this is consistent with hypogonadism.²

While hypogonadism is most common in older males due to the natural decrease of testosterone with age, it may occur in younger males. Certain medical conditions can cause low testosterone production or result in the removal of one or both of the testicles, such as cancer or injury.³

According to the American Urological Association, it’s estimated that low testosterone levels affect roughly 2% of men.³ So for many men, testosterone replacement therapy can help with the many unwanted symptoms.

What Are the Symptoms of Low Testosterone?

Low testosterone levels affect many different parts of the body and can cause symptoms such as:³

  • Low sex drive

  • Fatigue

  • Decreased muscle mass

  • Obesity

  • Mood changes, such as irritability and other symptoms of depression

  • Reduced erectile function

  • Loss of body hair

  • Decreased growth of facial hair

  • Depression

Not only can replacing testosterone improve the symptoms of hypogonadism, but it can also result in many other benefits.

What Are the Benefits of Testosterone Replacement Therapy?

The benefits of testosterone aren’t limited to improvements in sex drive, hair growth, and muscle mass. Improving testosterone levels to normal ranges can positively impact parts of the body such as the brain, heart, and blood cells.

Additional benefits of testosterone include:¹

  • Preservation of memory 

  • Improvement of brain health

  • Prevents the heart from going into certain life-threatening rhythms (Torsades de pointes)

  • Reduces the risk of heart attack and stroke

  • Improves blood sugar levels in those with diabetes

  • Helps to maintain a healthy weight

  • Helps with production of red blood cells by increasing the levels of erythropoietin 

We now know that testosterone replacement doesn’t increase the risk of CVD but that it actually reduces the risk of CVD like heart attacks and strokes. Additionally, low levels of testosterone have been linked to an increased risk of CVD and overall death.⁴ 

But this conclusion is one that’s rooted in controversy. 

The Controversial History of Testosterone Replacement Therapy

Before the year 2010, there were over 200 studies that showed the cardiovascular benefits of testosterone. Specifically, these studies proved that lower levels of testosterone in men were associated with increased rates of CVD and overall chance of death.⁵

Additionally, some studies demonstrated that repleting testosterone to normal levels can decrease cardiovascular risk.⁵

Between 2010 and 2013, four studies were published that suggested that testosterone replacement therapy increases the risk of CVD. However, it’s important to note that only one of these studies was a randomized, placebo-controlled trial. This means that participants in the study randomly received either testosterone or a sugar pill. These types of studies provide the highest levels of evidence without increasing the risk of bias.⁶

So when you take into account the types of studies done, only one study out of over 200 suggested that testosterone replacement increases the risk of CVD.

Despite this, the FDA issued a warning in 2015 for testosterone therapy and risk of CVD. In addition to this, they also required manufacturers of testosterone to conduct additional research to specifically look at the risk of heart attack and stroke. 

The findings from this research were published this past summer (July 2023), and they’re known as the TRAVERSE trial.⁷

The TRAVERSE trial was a randomized, double-blind, placebo-controlled study, and it was the largest study of testosterone therapy in men. The trial consisted of over 5000 men that met the following criteria:

  • Testosterone levels less than 300 ng/dL

  • Age between 45 and 80 years old 

  • Known CVD or having three or more CVD risk factors

CVD risk factors include conditions such as high blood pressure, high cholesterol, diabetes, tobacco use, and obesity.⁸

Results of the trial showed that there was no difference in CVD risk between the men taking testosterone versus the men not taking testosterone. So this helps to prove that testosterone therapy doesn’t increase the risk of CVD such as heart attacks and strokes. 

How Does Testosterone Replacement Decrease the Risk of Heart Disease?

So we know that taking testosterone doesn’t increase the risk of CVD but that it actually does the opposite. But how?

For the most part, whether or not someone will have a heart attack or a stroke isn’t random. Typically, people that develop CVD will have risk factors for it, such as:⁸

  • High blood pressure

  • High cholesterol

  • Obesity

  • Prediabetes or diabetes

  • Tobacco use

  • Lack of regular physical activity

Testosterone replacement helps to improve many of the risk factors associated with CVD. Specifically, testosterone replacement therapy:¹

  • Improves cholesterol

  • Improves insulin sensitivity

  • Lowers blood sugar and Hemoglobin A1c

  • Decreases weight and body fat levels

  • Reverses plaque deposits in the walls of blood vessels, which causes heart attacks and the majority of strokes

  • Dilates blood vessels, which can lower risk of high blood pressure

However, testosterone therapy can come with some risk. The TRAVERSE trial did show a slight increase in the risk of blood clots, a heart condition called atrial fibrillation, and injury to the kidneys. My suspicion is that the development of these conditions may be due to the population in the trial being older and already at an increased risk of these conditions.⁷

In regards to the development of blood clots, the men in the trial may have already experienced hardening of and plaque build up in the arteries as a result of low testosterone levels. So when testosterone levels started to be repleted, this may have changed things in the arteries just enough to result in a clot being moved from the vessel wall into the bloodstream. 

But it’s important to remember that with many things in medicine, the benefits and risks of treatments need to be considered. In this case, the low risk of developing these conditions certainly outweighs the many benefits of testosterone replacement therapy. 

Do You Have Symptoms of Low Testosterone Levels?

No matter what your age is, if you have one or more of the symptoms of low testosterone levels, I suggest that you get your levels checked. As mentioned before, hypogonadism is easily diagnosed with a blood test, and treatment can result in improvements in quality of life and reduction of risk of heart attack and stroke. 

If it seems like the research surrounding HRT for men and women has changed a lot over the last few years, it’s because it has. When it comes to medicine in general, staying up-to-date on studies and research is so important, and it’s something that I always make sure to do. 

So if you have questions about HRT, if you’re looking to have your testosterone levels checked, or if you have hypogonadism and are curious about treatment options, please visit your primary care provider if they understand how to treat this, or get established with a functional medicine or naturopathic medical provider who specializes in hormones. If you are in my practice, please contact my office today to schedule an appointment if you would like to discuss this further.