Effects of Testosterone Replacement Therapy on Muscle Mass

Dr. Zach Long // #FitnessAthleteFriday // www.ptonice.com 

In today's episode of the PT on ICE Daily Show, Fitness Athlete faculty member Zach Long discusses Testosterone Replacement Therapy, including research supporting its use, side effects, understanding dosing, and common clinical presentations related to TRT use.

Take a listen to the episode or read the episode transcription below.

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EPISODE TRANSCRIPTION

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ZACH LONG Good morning, everybody. Welcome to the PT on Ice Daily Show. It is Fitness Athlete Friday, the best day of the week here on the podcast. I'm excited to be with you as your host, Dr. Zach Long. And today we're going to talk about a topic that's a little out there, like it's not something we talk about a whole lot in the profession, and that is testosterone replacement therapy. And we're going to discuss four or five things that I really believe that those of us in outpatient orthopedics need to understand about testosterone replacement therapy because you are for sure seeing these patients in your clinic with certain conditions and being aware of a few things will help you out clinically. Before we jump into that topic, upcoming courses that we have inside the fitness athlete division. Our live course is, we have one more for the end of the year. That's Colorado Springs, Colorado this weekend. Mitch will be teaching that. If you can't make it to that in quarter one, we will be in Portland, Oregon, Richmond, Virginia, Charlotte, North Carolina, and Boise, Idaho. So check out those courses, pglnice.com. We also have our advanced concepts course. We'll be going live at the beginning of the year. That course always sells out. If you've already taken level one, you can jump into the online level two, but that sells out. So you want to look at jumping in and booking your spot as quickly as possible.

TESTOSTERONE REPLACEMENT THERAPY Let's jump into testosterone replacement therapy and what physical therapists need to know about that. Testosterone replacement therapy is injecting testosterone into your body, which is the male sex hormone, prescribed by doctors at times to treat hypogonadism. We've seen a giant increase in the number of people and the acceptance of people being on TRT in the past few years and I think that's why it's so important for us to understand that because so many individuals are now when they you know get into that 35 40 50 year old age range where their libido goes down a little bit. They stop improving quite as much in the gym as they used to. They start to have a little bit more general fatigue, anxiety, et cetera. We're seeing more and more men jump on TRT. I found a research study from 2017 looking at the rates in the US population of people being on TRT. And in 2017, they estimated that between 1% to 3% of men were on testosterone replacement therapy. which that number was a threefold increase in the number of prescriptions of TRT from 2007 to 2017. So threefold increase in those 10 years. And I would even say since then, in my opinion, it has become more popular or at the very least more accepted. Back in 2017, you wouldn't hear a whole lot of people talk about being on TRT. And now I feel like I see it all the time. I see big time influencers talking about being on TRT. all the time on social media, when I'm talking to people at the gym, they're regularly talking about their doctor just put them on TRT, whatever. So there's a lot less stigma around it and there's a lot more people getting on it. And I think that's really important for us to understand because there are gonna be a few things that we see in the clinic in people that are on TRT. And so asking this question more frequently to your male patients, especially that are between the ages of say 30 and 50 years old, is going to change a few things that you might be thinking of clinically. So three-fold increase in those 10 years and probably a little bit more than that. Another really interesting study that I found with testosterone replacement therapy was this study called Testosterone Dose Response Relationships in Healthy Young Men. So this was a really cool study where they took individuals that had previous resistance training experience and they told them that they weren't allowed to exercise during this six-month study. So If they've done previous resistance training, we kind of know that they're going to be through their beginner gains, their newbie gains in the gym where they would have really easily put on several pounds of muscle. So these aren't people that you're going to expect to see drastic increases in muscle mass in a short period of time. especially when they're not working out. But what they did in this study was for six months, they put these men on testosterone replacement therapy at different dosages. So the dosages were 25, 50, 125, 300, and 600 milligrams of testosterone for 20 weeks. So a wide range of doses from 25 milligrams a week to 600 milligrams a week. And they looked at a number of different things, such as their fat-free mass and their leg press strength, and then a number of other different physiological factors. But I'm gonna focus on those two, mostly muscle mass here. So again, we wouldn't expect these individuals when they're not resistance training, but having had previous resistance training experience to gain a lot of muscle mass in this time period. But what they found was that the group on 125 milligrams a week during those six months gained six pounds of muscle on average. The group at 300 a week gained 12 pounds of muscle mass on average and the group at 600 milligrams a week gained on average 19.5 pounds. So a lot of increase in muscle mass during that time period, especially when people aren't doing any resistance training.

UNDERSTANDING TRT DOSAGE And so I bring those dosages up because I think that's one really important thing when you have a patient on testosterone replacement therapy, I want to know what that dosage is. So when you're treating hypogonadism, less of this like people getting on TRT to try to improve their sports performance, their aesthetics, their strength, et cetera. What you tend to see is much lower doses in terms of testosterone replacement therapy. Like getting on those low doses under typically 200 milligrams a week is what you'll see a lot of doctors prescribe here. And that's going to do a lot to help improve libido and anxiety and other symptoms like that of hypogonadism. But when you get to that 125 milligrams a week, that's when we start to see a large increase in muscle mass. And what you'll often hear referenced by doctors prescribing TRT is sports TRT dosages versus hypogonadism dosages. And the cutoff there that you'll hear most people discuss will be 200 milligrams a week. So when you're taking 200 milligrams or more, that's when you're getting into a bit more of the sports performance arena than just purely addressing hypogonadism. And I think that's important because of the next studies that we'll talk about in a second here. But 200 milligrams a week, when people are on that, I'm thinking, all right, we're on a pretty good dosage. And if we go back to that study where the milligrams per week range from 25 to 600. It's important to note that testosterone is obviously a performance-enhancing drug. It can be used for medical reasons. It can be used for recreational and sports performance reasons. And when people typically do like a steroid cycle, not TRT, like trying to put on as much strength, muscle mass, sports performance as possible, the dosages that people will typically be at will be at 300 or more. Typical dosage that you'll hear a lot of people talk about doing a starter steroid cycle is like 500 milligrams a week So this study was really aggressive in the dosages that they did there like especially the group that was doing 600 milligrams a week for six months like they were doing a full-blown steroid cycle, but remember 200 milligrams a week is kind of your cutoff there in terms of sports TRT versus just standard TRT.

THE RELATIONSHIP BETWEEN TRT DOSAGE AND TENDINOPATHY Why that's important and why I want to know the dosage that my patients are on if they're on TRT is because One thing that I clinically see quite a bit is that those individuals on TRT, I'm frequently finding them showing up to the clinic with tendinopathies more than any other injury out there. In fact, when I see a male between the ages of 30 and 50 years old that's coming to me with a tendinopathy and I know that they're exercising and they look relatively fit, this is a question that I will just straight up ask them. because I think it's valuable information to know. And the reason why it's valuable is that there are actually two research studies out there that have found, one of them found an increased risk of rotator cuff tears in men on testosterone replacement therapy, and another one found an increased risk of distal bicep tendon tears and increased risk of needing surgical intervention to repair that distal bicep tendon tear. And so if we know from these two research studies that these men on TRT are at increased risk of a tendon tear, that would suggest that there's likely some degeneration already happening to some tendons in men that are on TRT. Now, why that is? Can't for sure say though. One theory could be here when we go back to that dose-response relationship study where men taking 125 milligrams or more per week are putting on significant amounts of muscle mass in a six-month period. It could be. those muscles are responding really fast, and those tendons are responding a little bit lower. It could be that maybe these men had low energy, anxiety, depression, they get on TRT, now they're feeling better, and they go from a low amount of activity to getting more aggressive in the gym, so they see training load spikes that challenges those tendons more than they're able to recover from. Whatever reason that is, it happens. We're probably seeing degenerative changes in tendons of men on TRT.

TENDON HEALTH ON TRT And we need to be aware of that because that might lead us to want to have more discussions with individuals. on taking care of their tendons if they're on TRT. Like maybe they need to spend a period of time every few months doing heavy, slow tempo work on their spots. Like if you're in CrossFit, maybe not always bouncing out of the bottom of the hole as aggressively as possible. Maybe they have to spend a period of one month every six months where that tempo's going really slow. Maybe we need to be prescribing some extra rotator cuff loading, tendon work, or maybe even different supplements that might have a positive effect on their tendons, such as taking Collagen and vitamin C. There's some research by Keith Barr on that potentially having some positive effects on our tendon health. But that's definitely something worth discussing and having in the back of your mind when you see men taking testosterone replacement therapy is what can you do to help improve their tendon health?

INJECTION SITE MATTERS WITH TRT And then the final thing that I think is important for us to understand with TRT, I would have never thought of this unless Jordan Berry, my business partner at Onward Charlotte, also a faculty member for ice in our spine division, hadn't treated somebody that was on TRT and came into the clinic with incredibly debilitating neural tension. So this guy had previously been a bodybuilder that had abused performance enhancing drugs and now was on TRT, but the guy could barely walk, couldn't pick anything up off the ground, had a 10 degree straight leg raise. As Jordan evaluated the guy's lumbar spine, the lumbar spine was completely clear. And Jordan kind of recognizing in this guy's body type that he looked like somebody that may have previously or currently was on performance-enhancing drugs, Jordan went ahead and kind of broke out that with the individual, started talking to him about his previous performance-enhancing drug history. It turns out the guy was still injecting testosterone regularly. He was on TRT after years of being on more performance-enhancing drug dosages of that. And Jordan asked him where he was injecting. And the guy was injecting his TRT dead center in the middle of his… to inject TRT or the place that's safest to inject it is actually going to be glute med. So if I'm looking at your butt from behind, if I drew a line straight down the middle of your glute, both horizontally and vertically, we want to be in that upper outer quadrant or in the vastus lateralis. Those tend to be the safest areas to needle. When he was going dead center in the glute, he was constantly hitting his sciatic with his injections. And so hitting his sciatic nerve as he was giving himself TRT injections resulted in some scarring on that nerve. And that was what was leading to his intense sciatic and neural tension. So I hope that gives you some ideas and things to think of clinically when you see guys on TRT, or at least makes you more aware of the prevalence of this, and that when you see people with it, you might want to be thinking of some different strategies and different questions if they're coming in with things like tendinopathy or weird neural tension. Hope that helps. Hope we see you on the road at a future Fitness Athlete Live course. Have a great day, everybody.

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