What is testosterone therapy?

Testosterone therapy is an important intervention for men with low testosterone levels. Learn more about signs and symptoms of low testosterone and therapy to treat it from Baylor Medicine urologist Dr. Blair Stocks.

What is testosterone?

Testosterone is the key male hormone that initiates and drives the development of male secondary sexual characteristics during puberty – like growth of facial hair and a deepening voice – and reproductive function.

“Testosterone levels peak at puberty. Over time, however, testosterone levels can naturally decline, leading to an array of clinical symptoms,” said Stocks, assistant professor in the Scott Department of Urology at Baylor.

When testosterone levels decline, males might experience symptoms like low energy levels, fatigue, low libido, problems with erectile function, loss of muscle mass and bone density and depressive symptoms. Someone who presents with these symptoms might have low testosterone, and testosterone therapy may be warranted. While most men diagnosed with idiopathic hypogonadism (or low testosterone) present in their 50s to 60s, younger men also can suffer from low testosterone levels and be symptomatic.

Formulation options

There are different ways in which one can take testosterone therapy. For exogenous testosterone, or obtained from an external source, the most common mechanism is injectable therapy. Patients typically inject themselves once a week and follow-up with their provider with regular visits and clinical lab monitoring.

Testosterone pellet therapy is another option. This procedure involves a small incision into the gluteal fat tissue. A provider will then inject a number of pellets into this tissue, which provides stable testosterone levels over a three-month period. This option is beneficial for those who are needle averse.

Oral forms of testosterone therapy also exist that are now safe for the liver. In the past, oral testosterone formulation was first processed by the liver, which could result in damage to the liver. Newer formulations are absorbed through the lymphatic system, thereby passing the liver. This is another good option for those who do not like needles. These are generally taken twice a day.

Testosterone gels or creams are a great option for first timers. These are applied daily on the outer arms, abdomen or inner thighs, however, if there is any risk of transference (e.g. interaction with children), patients should shy away from this option.

“Overall, we have a very patient-centered conversation to decide how to best deliver testosterone therapy,” Stocks said.

Side effects

Testosterone therapy provides positive benefits including:

• Improvements in mood and energy levels.
• Fighting daytime fatigue.
• Improvements in libido/sexual drive.
• Increased bone density and muscle mass.
• Loss of visceral fat tissue.

There are several physiologic side effects that should be closely monitored while a patient is on testosterone therapy. These include increases in blood pressure and hematocrit (or percentage of circulating red blood cells) and changes in cholesterol, which include lowering of good cholesterol (HDL) and increasing bad cholesterol (LDL).

“A major concern is that testosterone therapy will cause a heart attack or stroke,” Stocks said. “However, in 2023 the TRAVERSE trial was published in the New England Journal of Medicine that directly answered this question. In this large randomized control trial, the authors evaluated the cardiovascular safety of testosterone therapy in men aged 45 to 80 with hypogonadism and preexisting cardiovascular risk. Over a median follow-up of 22 months, testosterone therapy did not significantly increase the risk of major adverse cardiovascular events such as heart attack or stroke compared to placebo.”

Testosterone monotherapy brings the risk of infertility. When taking testosterone, the body sees no need to produce its own testosterone, thus the high levels of intratesticular testosterone required for sperm production are lost. Consequently, the production of sperm decreases, and a male can become subfertile or even infertile.

“There is a big counseling factor for younger patients with low testosterone interested in testosterone therapy, and we often explore other ways to increase testosterone,” he said.

Higher doses of testosterone can lead to transient acne while the body acclimates to new hormone levels, but this usually self-resolves over time. Hair loss also can be common.

Changes in mood are attributable to taking testosterone, which naturally gets converted to estrogen. Higher estrogen levels in males can lead to mood swings and irritability, so experts monitor this closely.

Overall, men with symptoms attributable to low testosterone levels should see a specialist trained in male hypogonadism.

“You should live a healthy lifestyle to see positive benefits of testosterone,” Stocks said. “Eat well, exercise regularly and follow up with your primary care doctor to make sure any other conditions are being treated.”

Learn more about Baylor Medicine Urology.

By Homa Warren