Josh Duhamel is opening up about his use of testosterone replacement therapy − an increasingly popular supplement option among men that some may take without understanding the potential risks.
On Dave Asprey's "The Human Upgrade" podcast on Sept. 16, Duhamel, 53, said he learned he had low levels in his early 40s.
"I feel better now than I did in my early to mid-30s," the actor said, adding he injects testosterone three times per week. "I'm not even kidding you. My joints, my back, my knees. I just feel stronger."
Other public figures like Joe Rogan and Dax Shepard have also spoken about their use of the hormone therapy. And it's made headlines with Defense Secretary Pete Hegseth announcing the U.S. military will begin testing troops' testosterone
levels.
Here's what to know, according to experts, including potential risks.
What is testosterone replacement therapy?
Testosterone, which is a hormone produced in both men and women, plays an important role in maintaining muscle mass, bone density, red blood cell production, energy levels, mood and sexual function.
"For men with clinically confirmed testosterone deficiency, testosterone replacement therapy can help restore normal libido, improve erectile function, increase energy and improve overall well-being," Dr. Arthur Burnett, professor of urology and oncology at the Johns Hopkins University School of Medicine, recently told USA TODAY.
When it comes to treatment, it should be aimed at restoring a true deficiency back to normal, not "enhancing performance or redefining masculinity," Burnett added.
Plus, testosterone naturally decreases over time. "That's part of normal biology − not every lower value represents a medical deficiency," Burnett added, noting a lab test showing a low testosterone level is not typically enough to justify treatment.
Instead, testosterone deficiency should be diagnosed through both appropriate laboratory testing and symptom evaluation. Other potential causes of symptoms, such as thyroid disease, sleep apnea, obesity, medication effects or depression, should also be considered and addressed, he said.
Are there risks to testosterone supplements?
From 2016 to 2019, prescriptions for testosterone replacement therapy (TRT, or “T”) have increased by 20%, as more men are reaching for the supplements in the hopes of enhancing their physical performance. But, many are unaware of the drug’s impact on their fertility.
"If someone has a normal production of testosterone and is given exogenous (or, external) testosterone, we can shut down the normal endogenous (or, internal) production of testosterone, meaning the patient becomes 'dependent' of external testosterone. This can cause infertility in men," Dr. Rocio Salas-Whalen, endocrinologist and obesity specialist, previously told USA TODAY.
Other risks of TRT can include worsening sleep apnea, acne or other skin reactions, stimulating the growth of existing prostate cancer, enlarging breasts, limiting sperm production and causing the testicles to shrink, and stimulating too much red blood cell production, which contributes to the increased risk of forming a blood clot.
Celebs are getting real about TRT: 'Make sure you're doing it the right way'
On his podcast in 2018, Rogansaid he started TRT when he turned 40 to "feel way better" and make his body “work way better." But he also cautioned against going overboard with testosterone.
"Get to a point where you have the hormone levels of a healthy young man," he said. "You don't want to be higher than that. That's when you run into problems."
Duhamel said he "probably got some bad batches here and there" when he started taking testosterone, explaining he didn't have a quality source.
His own experience is what inspired him to cofound Gatlan, a men's health company that offers physician-guided testosterone replacement therapy and other treatments.
"We don't want people to be going all willy nilly with this," Duhamel said. "This is your body, this is your health. Make sure you're doing it the right way."
This article originally appeared on USA TODAY: Josh Duhamel feels 'stronger' with testosterone. What to know about the therapy
