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Your Bones Are Alive

Most people picture the skeleton as a rigid frame — inert scaffolding that holds everything else up. It isn’t. Bone is living tissue, constantly broken down and rebuilt, and it responds to stress exactly the way muscle does: load it, and it grows stronger and denser. That one fact changes the whole question. Bone health isn’t something you’re stuck with — it’s something you build, and the same training that builds muscle is reinforcing the skeleton underneath it.

The rebuilding runs on a process called remodeling: specialized cells called osteoclasts clear away old, damaged bone while osteoblasts lay down new tissue. Peak bone mass arrives in the late twenties to early thirties, and from there it’s a slow decline — faster for anyone inactive, under-eating, or skipping resistance work. The most effective defense is loading bone on purpose. Strength training pulls on bone and signals it to densify, and it builds the balance and stability that prevent the falls that fracture weak bone in the first place. Plyometrics — jumping, hopping, the explosive movements most people skip — add the dynamic, high-impact load that bone responds to best, especially in the hips and lower body where osteoporotic fractures tend to happen. And these habits compound, so the work done in your twenties, thirties, and forties sets your fracture risk decades later.

Movement only pays off if the raw materials are there, and strong bone is a team effort. Calcium is the building mineral, but it needs vitamin D to be absorbed, magnesium to keep its balance, and vitamin K to direct it into bone rather than into blood vessels. Protein matters more than most people assume — bone isn’t pure mineral, it’s built on a protein matrix, largely collagen, that gives it flexibility and structure (and collagen isn’t just for women). Chronic under-eating and crash dieting starve that whole system. Sitting on top of all of it are the hormones: estrogen slows bone breakdown in both sexes, which is why loss accelerates after menopause; testosterone supports bone-building; and chronically elevated cortisol — from stress, poor sleep, or long-term steroids — tips the balance toward loss.

That interconnection is what makes the GLP–1 question more complicated than the marketing suggests. The medications aren’t villains — for the right person they’re a genuine tool. But rapid weight loss strips muscle along with fat, and appetite suppression can drop protein and nutrient intake too low to maintain bone. Push the first domino — the number on the scale — and muscle, bone, and recovery fall behind it. Current research ties the bone concern more to that muscle loss and reduced loading than to any direct effect of the drug, and it points back to the same protections that build bone in the first place: enough protein, calcium, and vitamin D, plus resistance training. Which is the reassuring part — bones are more in your control than they feel. Ask for bone-density and hormone markers at the next blood draw, train with load and impact, eat enough protein, and start early, because this is a skeleton you build over decades, not weeks. No adamantium required.

KEY TAKEAWAYS

  • Bones are living tissue, not a static frame. They constantly remodel — osteoclasts break down old bone, osteoblasts build new — and they respond to load just like muscle does.
  • Use it or lose it. Peak bone mass arrives in your late twenties to early thirties; after that it declines, faster if you’re inactive, under-eating, or skipping resistance training.
  • Muscle and bone are directly linked. Building muscle pulls on bone and helps maintain density — so strength training does double duty.
  • Plyometrics matter and get ignored. Jumping, hopping, and explosive movement load the hips and lower body where fractures happen. Start early; they get harder to begin later.
  • Bone nutrition is a team. Calcium needs vitamin D to absorb, magnesium and vitamin K to be directed properly, and protein/collagen to maintain the bone’s structural matrix. Collagen isn’t just for women.
  • Hormones set the balance. Estrogen (in both sexes), testosterone, and cortisol all influence whether you’re building bone or losing it — which is why bone loss accelerates after menopause and with chronically high stress.
  • GLP–1s deserve nuance. Useful for the right patient, but rapid weight loss can cost muscle and bone, especially if protein and training fall off. Current research links the concern to muscle loss and reduced loading more than to a direct drug effect — and resistance training plus adequate protein, calcium, and vitamin D are the recognized protections.
  • It’s a domino chain. People focus on the first domino (the number on the scale) and miss everything connected behind it. Looking skinnier isn’t the same as getting healthier.

Links & Notes

Pete Wright:
Hello everybody, and welcome to Build for Health, the show that redefines strength, because muscle isn’t just for looks. I’m Pete Wright, and I’m here with Coach Srdjan Injac, and today we’re building a body that’s built to last. Our topic: bones.

All right, man, we came out of last week and you were fired up. I haven’t seen you so prepared for a podcast like this yet. You are sending me notes and texts, and we are ready to go. We’re talking about bones. What is on your mind, and do you need some sort of an intervention?

Srdjan Injac:
No, it’s just somebody mentioned something, and that kind of triggered me, and I’m like, okay, I gotta talk about this. And you said bones, and I remember having a conversation with one of my clients about this. They didn’t really know much about bones — how important they are, how they get affected throughout the years, all of that. And I had another one asking me, because she’d like to lose some weight, if she could use some medication, that GLP-1 and all that stuff. And I’m like, all right, we gotta talk about this.

Pete Wright:
Okay, so bones. When I think of bones, I usually think of Scooby-Doo being chased by a skeleton. I know very little about bones. So I think we need to start at our most basic. What are bones, man? What’s going on with bones, and why are we concerned about our bones right now? It seems like such a dumb question, but I really need to start there.

Srdjan Injac:
Well, everyone, when they think of bones, they think they’re static — but they aren’t. They’re living tissue that responds to stress. When you lift weights, jump, sprint, anything like that, the bones get a signal to become stronger and denser.

Pete Wright:
Wait, wait — seriously, though? You’re telling me this? Why am I just learning this now? I come to you to build muscle, I thought. And now you’re telling me my bones are actually getting a signal to get stronger too?

Srdjan Injac:
Yeah, they’re directly related, the muscle and the bones. They’re directly linked. The stronger your muscles are, the more tension they place on bones, which helps maintain and build that bone density. So me building your muscle mass, building you stronger, bigger muscles — I’m also helping you with the bones themselves.

So it’s not that they’re just this rigid structure holding the body together. The bones are actual living tissue, and they’re constantly going through a process called remodeling, where old bone is broken down and new bone is rebuilt. These specialized cells called osteoclasts remove old and damaged bone, while osteoblasts build the new bone tissue. That whole process is influenced by nutrition, hormones, physical activity, age, and overall health. But peak bone mass is usually reached somewhere around your late twenties, early thirties. After that, most people gradually begin to lose bone density over time — especially if they’re not active, or they’re under-eating, or not doing resistance training.

Pete Wright:
All right, so as you can see here, I’m shocked. We need to talk about what I can do to actually impact my bones, because they feel pretty deep. Seems hard. What sorts of factors play into what I can control about my bone health? Before we start talking about supplements and things, let’s talk about movement first.

Srdjan Injac:
Yeah, there aren’t really that many supplements. It’s more the things that affect bone strength and density, and how you can actually repair those bones and get them stronger. Through resistance training, plyometrics — we can go into detail with that — and then nutrition, which plays a massive role in bone health, and then the hormones and how they affect bone health. So we can break it down.

Pete Wright:
All right, let’s start with resistance training. What is happening to my bones under resistance stress?

Srdjan Injac:
That’s probably one of the most effective tools to prevent and slow down what’s called osteoporosis — losing bone — because the bones adapt to stress just like muscles do. When you lift weights or perform any kind of strength exercise, the muscles pull on the bone they’re attached to. That mechanical tension sends a signal to the bone that it needs to become stronger and denser to handle that load. In response, the body stimulates bone remodeling and increases the activity of osteoblasts, the cells responsible for building new bone tissue. Over time, this can help maintain and improve bone density.

Another major benefit of resistance training is that it builds muscle, balance, coordination, and stability. That matters too, because one of the biggest risks of osteoporosis is falling and fracturing those weakened bones. And then you get plyometrics as well, which people kind of ignore.

Pete Wright:
Okay, what are plyometrics?

Srdjan Injac:
So plyometrics are jumps — putting more impact on the bone. Impact-based exercises can be really beneficial for bone health, because bones respond especially well to forces that are dynamic and high-impact. So jumping, hopping, skipping, those explosive movements — they create a brief but powerful loading force through the skeleton. That impact stimulates the bone tissue to adapt and get stronger, particularly in the hips and lower body, because that’s where osteoporosis fractures usually happen. So if you can do some plyometrics, do them. It’s important that you don’t wait until you’re older to do that stuff. Start early.

Pete Wright:
Yeah, I imagine any of those explosive movements get harder to start the later you start.

Srdjan Injac:
Yeah. In reality, the habits you build in your teens, twenties, thirties, and forties have a massive impact on your risk for osteoporosis and fractures later in life. So make sure you put that into your routine, along with resistance training.

Pete Wright:
All right. Next is nutrition. What are my bone foods?

Srdjan Injac:
Nutrition plays a massive role in bone health, because like we said, bones are living tissue that constantly need raw material to rebuild, repair, and maintain their structure. Most people think about calcium, but strong bones depend on a combination of nutrients working together. Calcium is important because it’s one of the main minerals stored in bone tissue. But without enough vitamin D, the body can’t absorb and use that calcium effectively — vitamin D helps with calcium absorption. Then magnesium helps regulate the calcium balance and supports bone structure, while vitamin K helps direct calcium into the bone instead of letting it accumulate in places like the blood vessels. So all these vitamins have to be taken together. They work well together.

And then protein. It’s not just for muscle — it’s another huge factor that gets overlooked. The bone isn’t made purely of minerals; it also contains a protein matrix, mainly collagen.

Pete Wright:
Mm-hmm.

Srdjan Injac:
And that gives the bone flexibility and structure.

Pete Wright:
Inside the bone.

Srdjan Injac:
So without adequate protein intake, the body has a harder time repairing and maintaining bone tissue. This is one reason chronic under-eating, crash dieting, and extreme restrictive diets can negatively affect bone density. So make sure you take collagen. Collagen is not just for females — usually when you mention collagen, it’s women who take it, and the guys don’t. It’s for males too. I drink my collagen every morning. I mix it with my water, take my multivitamins, and get my collagen in. That’s separate from the protein I take later in the day, after the workout. I focus on my protein intake, but collagen is separate — I take it every morning.

Pete Wright:
Well, I guess I’m in a stereotypical relationship, because I’ve never even considered collagen, and I know my wife takes it every day. All I hear is, “Whoa, it’s so disgusting. Oh my god, it’s just awful.” But she does it every day, and I’ve never once had it.

Srdjan Injac:
Yeah, you should try it.

Pete Wright:
Okay.

Srdjan Injac:
It’s really not bad. You have the ones that are tasteless, and then I just mix it with my electrolytes, with the LMNT, and I don’t really taste anything. It actually tastes pretty good.

Pete Wright:
Okay, I had never thought about mixing something with my LMNT.

Srdjan Injac:
Yeah, mix it. It tastes way better.

Pete Wright:
I love my — okay, I’m on board with this. All right. Next up is hormones. How is our hormone balance related to bone health?

Srdjan Injac:
Hormones are probably one of the biggest regulators of bone health, because they control the balance between bone breakdown and bone building. Since bone is constantly being remodeled — old bone being removed and new bone being created — hormones help determine whether that process stays balanced or starts shifting toward bone loss. When hormones are healthy and stable, the body is better able to maintain strong bone density. But when hormones become disrupted, or they decline with age, bone breakdown can start happening faster than new bone is rebuilt.

The most important hormone for bone health is estrogen. Although many people associate estrogen only with women, it plays a critical role in both men and women, and it helps slow down bone breakdown and preserve bone density. This is why women often experience rapid bone loss after menopause, because that’s when estrogen levels decline significantly.

Pete Wright:
Because estrogen declines.

Srdjan Injac:
But testosterone is also important, because it supports muscle mass, strength, and bone-building activity. Men with low testosterone levels also have lower bone density and an increased fracture risk over time. And then you have cortisol, the body’s stress hormone. Short-term cortisol is normal and necessary, but chronically elevated cortisol — from ongoing stress, poor sleep, or long-term steroid medications — can increase bone breakdown and interfere with the body’s ability to rebuild that tissue. Over time, that can contribute to weaker bones and the risk of osteoporosis. There are other hormones that matter too, like thyroid hormones.

Pete Wright:
The thyroid, yeah.

Srdjan Injac:
Yeah, they regulate metabolism and bone turnover.

Pete Wright:
Yeah.

Srdjan Injac:
So higher activity can accelerate bone loss. And insulin and growth hormone also support tissue growth.

Pete Wright:
So you are a month and a half, two months out from fracturing your arm. What were you doing with all of these bone considerations in mind? Anything different from your normal routine that you injected into your day-to-day over the last two months to help knit that bone back together? Or are you just always on top of it?

Srdjan Injac:
Well, I was taking my collagen — that was always there. But I also increased the vitamins and minerals. Instead of taking them through pills, I was going to the IV clinic and getting an extra boost of vitamin D, calcium, vitamin K, and vitamin B, to accelerate the repair. So I was doing a little bit more to help the bone heal. Plus, I kept trying to move my arm and work on the forearm muscles, trying to get them to start firing again. Pretty much everything else, I was already doing. There wasn’t really too much more.

Pete Wright:
Yeah, you’re kind of a hard specimen to talk about, because you’re already so attentive to all these systems. But I was curious, because our assumption is that your bone is knitting together ahead of schedule — how much of that is just because your routine includes a lot of these things already, versus things you did differently? I think that’s a very cool situation.

Srdjan Injac:
Yeah. Actually, earlier I was doing pull-ups. I was like, I gotta try it. I was able to hang, like, two days ago.

Pete Wright:
Jeez.

Srdjan Injac:
But I wasn’t able to do anything else. I’d hang for five seconds and my arm would start to shake, so I’d try not to push it too much. And then today I’m like, you know what, let me just jump on these Olympic rings and try to do some pull-ups.

Pete Wright:
On the Olympic rings, really?

Srdjan Injac:
Yeah, I’m like, just go for it. And I did five pull-ups, and then I started getting looks from the side, so I’m like, all right, I’ll go down, I’ll stop.

Pete Wright:
Okay. Yeah, it’s good that you live in an environment where a little shame can be thrown your way, just for your own safety.

So the last question — this came up because somebody asked you about GLP-1s and the relationship with bone health. What do we have to think about there?

Srdjan Injac:
Well, when they’re used as a medication, then I’m okay with it. But these days, most people use it just for weight loss — the Ozempic and all those. If you’re using a medication for blood sugar control, I get it.

Pete Wright:
Yeah, diabetes, yeah.

Srdjan Injac:
But one big concern that even researchers and clinicians have is how rapid weight loss from these drugs can impact bone health over time. One concern with GLP-1 medication is that it suppresses the appetite so much that some people end up eating far too little. They’re already not eating the right food, not getting enough protein as it is, and now, suppressing that appetite, they’re going to eat even less. So their calorie intake drops too low, especially protein. And because we get calcium, minerals, and nutrients through food, the body may struggle to maintain muscle tissue, bone remodeling, and that whole recovery process. Without food, you can’t expect the body to recover and function the right way.

During that weight loss, inadequate protein intake can increase the risk of losing muscle mass — which, like we said, is so directly connected to bone health. Muscle and bone are very closely connected, so you have to think about both. You can’t just think about the weight loss. The bones respond to mechanical loading, so you can work out, but if you’re not eating enough protein and rebuilding that muscle — and protein also helps the bone itself — it doesn’t work. So I’m not a big fan of that.

Pete Wright:
Yeah, they’re a pretty hardcore change to your system.

Srdjan Injac:
Yeah, it reduces the stimulus needed to maintain bone density. There are a lot of studies that show that concern, so you can see how it’s related. People are just focused on the weight loss itself. They don’t see how everything is connected — it’s like a domino. Seven, eight dominoes, and if you push one, they’re all going to go down. But people focus on the first two. They don’t see how those first ones affect everything else. It’s a big chain that’s all connected. So it’s not just that you look skinnier — you actually are not getting healthier. It’s getting worse.

Pete Wright:
I think that’s a really rational way to put it. I’ve had this conversation with my own physician about GLP-1s, and the entire discussion was around: look, we can try it, but one of the things you’ll notice is that you’ll have to work out more and take in more protein — and your behavior will change so that you will not want to do that. You won’t want to eat that much, you won’t want to eat enough, and what you do eat will be out of balance. It is totally possible to maintain a healthy lifestyle on a GLP-1 — absolutely possible, per my physician. But it’s so hard that most people don’t. They don’t have the rigorous training, they don’t have the routine, they don’t eat enough protein, they don’t keep the balance of their nutrients up — and that’s when they suffer. I haven’t read the research, but everything I’m hearing is that your behavior changes so dramatically, so quickly, that it can really harm all of these interconnected systems.

Srdjan Injac:
Exactly. Even for me — I’m so dedicated and disciplined when it comes to nutrition, I can flip a switch and be perfect with that. But it would probably be hard, if I were on that, to eat enough protein and enough food to get all the nutrients and minerals my body needs. It would be extremely difficult. And we’re talking about people who aren’t at my level, who aren’t used to this kind of lifestyle. They have a different lifestyle, so they’re not going to be able to maintain any of the muscle mass. Instead of teaching them how to do it the right way, how to eat right —

Pete Wright:
Yeah.

Srdjan Injac:
You know, it’s just —

Pete Wright:
But they also have a very different cognitive and emotional relationship with food. And that’s one of the things GLP-1s help to rewire.

Srdjan Injac:
Yes.

Pete Wright:
And that’s why it’s so emotionally fraught. We can sit here and say you just have to learn how to eat right. But for people for whom GLP-1s are perfect, it’s impossible to just say “go eat right.” They’re chemically wired not to be able to do that on their own. This is a support that is so eye-opening, but it’s super dangerous. I think that’s the trick — managing the risks.

Srdjan Injac:
I think they get addicted to it, because they start seeing the results, they start losing weight, they’re not hungry, and then they just stay on it. They love it, and they don’t want to get off it. It’s very addicting — but then it just gets worse and worse. If somebody’s two hundred fifty, three hundred pounds, really big people, and they get on it to suppress the appetite — because they’re probably eating five, six thousand calories of God knows what, processed food and things like that — I can see that helping them control the cravings. And then you slowly teach them how to eat right, wean them off it, and start exercising. But somebody who only has forty, fifty pounds to lose, or thirty pounds, I wouldn’t be giving them that. There are so many other ways you can go about it.

Pete Wright:
Yeah.

Srdjan Injac:
So, yeah.

Pete Wright:
Well, and the handoff is important, right? Because — I think you just said it — it’s addicting to get to that point. When you have 70 pounds to lose and you lose the first 40, you could probably start weaning yourself off the GLP-1s and start considering more rigorous training and building some new habits. But your body and brain are going to tell you you don’t want to do that.

Srdjan Injac:
Exactly. It’s addicting, just like steroids.

Pete Wright:
Yes, yeah.

Srdjan Injac:
Very addicting. But the feeling is amazing. It’s great, and they see the results, and they want more, and they just can’t stop. It’s hard to stop. It’s crazy.

Pete Wright:
And then their arms fall off at a competition.

Srdjan Injac:
Pretty much. And then they see all the negative effects, just like they’re going to see from the GLP-1. I know a few guys who destroyed their kidneys and livers and other organs because they just wouldn’t get off the steroids. It’s not worth it. So I was not for it when my client asked me, because she did not need it. She wasn’t really that overweight. She just wanted something fast, quick. Everyone’s looking for a shortcut, the magic pill. Nah, don’t do it.

Pete Wright:
Well, okay, so GLP-1s are complicated, but bones, it turns out, are less complicated, and you have some control. We’ve talked about resistance training, plyometrics, nutrition, and hormones, and these are all deeply interconnected systems. So — I’ve got a doctor’s appointment coming up. They’re going to do blood work.

Srdjan Injac:
Uh-huh.

Pete Wright:
I’m going to be asking for markers for these things, right? Are my hormones — am I getting the right balance of hormones, as a man of a certain age? Should I be looking at testosterone? How do we balance that out? Anything else?

Srdjan Injac:
You can ask them about that. Ask them about your bone health, bone density — they can test for that too. And then make sure all the hormones are perfectly balanced.

Pete Wright:
I’m a big fan of Wolverine, as a model character. Wolverine had the metal injected right into the bones. Are we there yet? Can we do that? I just don’t ever want to think about it again.

Srdjan Injac:
Oh, I wish.

Pete Wright:
I don’t ever want to think about it again.

Srdjan Injac:
I probably would try that. I like the idea of that.

Pete Wright:
All right. This has been great. Thank you, everybody, for hanging out and learning about bones today. We sure appreciate you and your time and your attention. Don’t forget, you can ask us a question — swipe up in your show notes, you’ll see the question link, and they’ll come right to us. We’ll answer them on an upcoming Q&A episode. And don’t forget to subscribe and share. If you’re listening to this on the website, sharing the show and subscribing is how we grow stronger together. Thanks for being here on Build for Health, and we’ll catch you in the gym next week.
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Hosted by Pete Wright and Srdjan Injac, Build for Health moves beyond gym culture to explore why muscle is critical for longevity, not just looks.