Build Muscle After 50 — Stunning Science You Need to See

Aging is not for the weak. Slow aging. Muscle repairs. Anti-aging. Aging in mice. The muscular system— Accelerate aging. Now maybe you've heard this, but I don't just mean it metaphorically, I mean it literally as well. The weak, those lacking in healthy functional muscle tissue, tend to die early. They fall and break a hip. They miss out on the brain-supporting hormones secreted by muscle. So I repeat, aging is not for the weak. The point I'm getting towards here is that muscle is your insurance in the longevity game. You need your muscle, you need to build it, and you need to protect it. But here's the positive twist: while a lot of us think of age-related muscle loss as an inevitable tax we pay for the time on this earth, it's not. Age-related muscle loss, or sarcopenia, is a result of specific molecular changes that happen with time, but these are identifiable and reversible. So in this video, we're going to pull back the curtain on one of those changes identified in a new paper. A new paper that had me giddy with excitement, so giddy that I, on the eve of my 30th birthday, was running to my 60-year-old mother saying, "Mom, let's do some push-ups together." 7, 14, 20. I think by the end of this video you're going to have the same energy, the same intellectual energy. But before we get to building up your body, let's work your mind and get into this paper. They performed deep molecular profiling on 1,013 individuals. Some new science. It's actually a modified version of another amino acid. So the next logical question to ask is, amino acid, but maybe not one you've heard of before. Well, the researchers found part of the answer lies in a phenomenon known as dramatically reduced liver fat. This reduces inflammation, thereby protecting muscles. And I want to look at some new science that was just published in Nature Aging on this exact topic: the loss of muscle mass with age. The medical term and clinical condition associated with this is called sarcopenia. Now, what did the researchers do? Well, the researchers set out to identify the metabolic signature of age-related muscle loss and sarcopenia. So to do this, they performed deep molecular profiling on 1,013 individuals aged 50 to 103. Yes, they did have a 103-year-old in this study. Now, among the molecules that stood out, one was called sarcosine. Sarcosine is an amino acid, but maybe not one you've heard of before. It's not the kind you'll find in your whey protein powder or ribeye steak or salmon. It's actually a modified version of another amino acid called glycine and goes by the alternative name of N-methylglycine. Science, where you can't be important unless you have at least two names. Ugh, I know. Anyway, the researchers found that sarcosine levels decline with age, not just in humans but in other species as well, like mice and monkeys, and to a similar extent. This is important because it suggests a conservation of physiology across species, and we'll get back to that in a moment. But anyway, more interesting, sarcosine levels were positively correlated with muscle mass and were depleted in individuals with sarcopenia. Of course, correlation doesn't prove causation. If you're listening to me, I'm guessing you already know that. So the next logical question to ask is, is this decline in sarcosine just a biomarker of aging, or is it actually contributing to age-related muscle loss? So to answer that question, the researchers turned to animal models. And here's where we come to Conservation of Physiology, because as much as I'd love to see a human randomized control trial on sarcosine supplementation over the decades, it will cost many millions of dollars and take years. So rather than keeping my fingers crossed for that trial that may— probably won't— drop in the year 2035, I'm going to talk about the animal models and hope the biology is conserved across species as we've suggested it might. So that said, you can take this research with a grain of salt, but the animal models are right now the best we have in terms of causal mechanism. Anyway, back on point, the researchers supplemented the aging mice with sarcosine and compared them to control mice. The results were really impressive. Sarcosine supplementation effectively prevented age-related muscle loss. And even more compelling, sarcosine didn't just preserve muscle, it also decreased overall fat mass, yielding leaner, more muscular animals. And what's more, sarcosine supplementation also activated fat tissue thermogenesis. That's the process of producing heat by burning calories, primarily through metabolically active brown and beige fat. So, put simply, in aging animals, Sarkisian increased muscle, decreased fat, and increased metabolism. Now, those findings alone should have you jumping for joy, both due to the sheer intellectual excitement of these data, and because, well, box jumps are a great leg exercise if you haven't done them. But do them safely, don't want to fall on your face. Anyway, the researchers then asked raises a deeper question: why do muscles decline with age in the first place, and how does sarcosine intersect in that pathway? Before we get to answering those questions, I want to take a little respite from our intellectual workout. I'll keep it short, but I want to thank the sponsor of this video, Chapter. In talking about healthspan and longevity hacks, I should mention, even if it's not sexy, the right health insurance can literally improve all-cause mortality. And that's not just a correlation, there's actually causal evidence for this. If you want more detail on that, see this letter. But that's why Chapter exists. It exists to help older Americans find the right health insurance for them, to save them both money and potentially life years. Chapter was founded by people whose parents themselves were scammed by sleazy Medicare brokers, so they became impassioned and they vowed to fix the system and built a model that does just that. Chapter searches every Medicare plan to match you or a parent or loved one with the right fit. And Shapr is fully independent and searches every Medicare plan available to find the one that truly fits your needs and priorities. The average user saves $1,100 per year. So if this could help you or a loved one, call the helpline we've set up: 815-STAY-CURE, as in stay curious. That's 815-782-9287. Metabolic health is life insurance, but you also need real health insurance. Now, back to our main narrative. Like I said, why do muscles decline with age? And what is the role of sarcosine in alleviating this process? Well, the researchers found part of the answer lies in a phenomenon known as inflammaging. It's a play on words, a spoonerism of aging and inflammation. Inflammaging is a chronic low-grade inflammatory state that develops with age and accelerates tissue breakdown. And in this study, immune cells called macrophages that are found in both muscle and fat were key players. Now, macrophages, they get to like this developmental fork in the road, and they can take on different fates—a pro-inflammatory fate or an anti-inflammatory fate, depending on their environment and their epigenetic programming. And in general—here's the catch—with aging, macrophages tend to shift towards the more pro-inflammatory fate, and that shift contributes to muscle degradation, fat gain, and sarcopenia. So enter sarcosine. The researchers found that sarcosine targets a pathway in these macrophages known as the GCN2 signaling pathway. And by acting on this pathway, sarcosine starves macrophage of specific amino acids. Yeah, you heard me right. Sarcosine itself, which is an amino acid, creates amino acid deprivation within the immune cells. And this nudges the macrophages towards more of an anti-inflammatory state, more of a youthful state. This reduces inflammation, thereby protecting muscles and activating fat thermogenesis and burning off total fat mass. And as just a quick aside, now that we're talking about fat burning, another striking dollop of data was that sarcosine dramatically reduced liver fat in the animals, which also tends to increase with age. So take a look at this figure here. It shows a clear reduction in liver fat. This is measured by something called Oil Red O staining, or ORO staining. In the stain, more blue tones suggest less liver fat, and that's quantified in the bar graph, so you can see the sarcosine dramatically drops liver fat. This all of course sounds like great news. So what should you do with it? Can you just eat more steak and eggs to boost sarcosine? Unfortunately no. Overall dietary protein intake doesn't meaningfully raise sarcosine levels. Like I said, this isn't something you can just get from a ribeye steak. So the next question is, Should you supplement sarcosine? Well, here's some things we know. First, human trials have not yet been conducted to test sarcosine's effect on muscles in aging humans. So we don't know yet if long-term supplementation of sarcosine in humans could carry great metabolic benefits or potential downsides. We just don't know. But I will admit sarcosine is widely available online, and the dosing used in mice has been translated to human dosing in the paper. So I can just quote from the paper: quoting, "The dose used was equivalent to 450 mg per day for a 60 kg human." That's the dose. You can go buy it online if you want. I have no affiliations. This is not medical advice. You just can. That said, there are certainly other steps you can take to offset age-related muscle loss. And if you want to learn more about particular nutrients and supplements that may help protect against sarcopenia based on human literature, Please check out the newsletter associated with this video. You can find it at staycuriousmetabolism.com and it's linked below. Those newsletters are usually where you can find even more in-depth content that doesn't make it into the video, including checklists, protocols, and additional practical lifestyle tips and takeaways. So check out the newsletter, it's linked below. And of course, make sure to continue resistance training, or start if you're not already. Nothing really replaces exercise and that will go a long way. A lot of age-related functional decline is caused by behavioral change. Yes, of course, there are metabolic changes too, some of which you can prevent, some of which you can't, or some of which you can't yet. But don't sleep on the behavioral components. Actually, wait, do sleep. Sleep is important. Just keep in mind there's a behavioral component. That's what I meant. Anyway, wrapping up, if there's one takeaway from this new research, it's this: age-related muscle loss isn't just a physical problem, it's a metabolic one. And while physical decline with aging has long been treated as inevitable, science is beginning to reveal otherwise. There may be options for you to avoid the metabolic tax of time. I think that's pretty exciting. The research is evolving, and I hope you stay with me here to see it evolve. Stay curious. Thanks. Now go do some push-ups. We're playing. Ready? One. Two. 3, 4, 5. Wow, you really can do this. 7, 8, 9, 10. You really go to 25? Yeah. Jesus. Okay, was that 13? Yeah. 14. Wow, I'm impressed. I think that's 18. Yep. 19, 20, 21, 22, 23, 24. Ugh. You can do it.