Cedars-Sinai Blog
Is Testosterone Replacement Therapy Right for Me?
Testosterone is popularly known as the hormone that makes men faster and stronger (and hairier), and also more prone to aggression and road rage. But testosterone plays a much wider and more significant role in the health of both men and women.
In the past two decades, men’s health has become a big topic, and testosterone has captured lots of attention. In particular, the use of testosterone replacement therapy, known as TRT, has surged. What used to be a treatment for mostly older men suffering erectile dysfunction has turned into a large industry marketing TRT to men of all ages as a way to build more muscle, boost energy levels and libido, sharpen them mentally and generally make them feel better.
In response to the demand, so-called low-T clinics and other online men’s health clinics have proliferated. According to one study, direct-to-consumer men’s health websites increased their unique visits 1688%—a nearly 17-fold increase—between 2017 and 2019.
So, should you be taking testosterone supplements? What do they do, and do they come with any side effects?
What Is Testosterone and What Is Testosterone Replacement Therapy?
“Testosterone is a hormone made naturally in the body by both men and women, although in men it’s made at much higher levels,” explained endocrinologist Nicolas Musi, MD, the Kathi and Gary Cypres Chair in Diabetes Research and director of Cedars-Sinai’s Division of Endocrinology, Diabetes and Metabolism.
In men, testosterone is made mostly in the testicles, and it plays an important role in the development of male sex characteristics, such as:
- Growth of the penis, testes and prostate
- Libido or sex drive
- Growth of facial and pubic hair
- Growth of muscles and bones
- Sperm production
“It also affects our mood, our sense of wellbeing and our thinking process and ability to concentrate,” said Musi.
Nicolas Musi Gomez, MD
Around age 40, men’s testosterone levels start to drop about 1% to 2% per year. Low testosterone, when the testes don’t produce enough, is called hypogonadism. Symptoms include:
- Reduced libido, erectile dysfunction and infertility
- Low energy, poor concentration and depression
- Loss of muscle, increased fat
- Poor bone strength
- Loss of body and facial hair
As the name suggests, testosterone replacement therapy is a way of replacing the missing testosterone and bringing it back to a “normal” level.
“There’s a lack of consensus over exactly where the cutoff should be,” said Howard Kim, MD, director of male reproductive medicine in the Department of Urology at Cedars-Sinai. “But low testosterone is generally considered to be between 200-300.”
That’s nanograms per deciliter of blood.
TRT comes in a few different forms: creams, patches, injections and pills.
Howard H. Kim, MD
How Do I Know if TRT Is Right for Me?
Low libido and erectile dysfunction are the best indicators that you should have your testosterone level tested. But testing it can be tricky.
“Testosterone levels have been shown to be very difficult to pin down,” said Kim. “First of all, you have to use a reputable lab. And you have to check multiple times to make sure you have the correct value, because it can fluctuate within the same person.”
Kim says if the test shows a low testosterone level and you have any of the symptoms, then you’re a candidate for replacement therapy. And studies show you’re likely to feel some benefits.
But what if your level isn’t that low? What if you just want to feel like all those young guys on social media who say they’re building muscle and losing fat, feeling energetic, mentally sharp, and lustful?
Musi and Kim both have words of caution.
“For testosterone to build muscle, we have to give high doses,” said Musi. “Bringing you to a low-normal level or a little higher won’t do it.”
And high doses have more potential adverse side effects:
- Sleep apnea
- Breast swelling
- Enlarged prostate
- Shrinking testes and infertility
- Increased risk of blood clots
- Acne
“Most importantly, your own testosterone levels will go to almost zero,” said Musi. “Your body says, ‘Oh, I'm getting all this testosterone from outside. Let’s shut down production.’”
“It’s not this magic elixir that’s going to solve all your problems.”
He says he sees a lot of young male patients who have been paying to get high doses of testosterone from a low-T clinic.
“They ask me to prescribe it,” Musi said. “They’ve stopped taking it because they don’t want to keep paying for it, but they can’t make their own anymore, and their levels are very low—and they feel awful.”
He says these men either have to ride it out, waiting six to 12 months for the body’s own production to start up again, or he will prescribe a low dose to help them feel better.
For men whose testosterone level is in the low-normal range, there’s not much clinical evidence that going on TRT to boost it a little will have any effect.
“We don’t want to discourage anyone from talking to their doctor and having their levels checked,” said Musi. “But if you’re just feeling a bit low-energy, fatigued or depressed, so many things could be responsible. It probably won’t be caused by low testosterone.”
“As far back as a century ago, it was thought to be a fountain of youth,” said Kim. “But it’s not this magic elixir that’s going to solve all your problems. Testosterone therapy may not be as dangerous as we think it is. But it may not be as helpful as we think it is, either.”
