How to Lose Fat AND Build Muscle

It is impossible to lose fat while building muscle. Or so we thought. Is it possible to learn this power? But there's nothing inherent in our biology that prevents us from doing both, effectively at the same time. Now it's true, in any given second, the body is usually in build-up or break-down mode. However, even over short time frames, the body can supply building components to one system, say muscle, and break down another. Say fat. Take this patient in our own Stay Curious Metabolism community, coincidentally named Nicholas N. Really. Over the course of about a year and a half, he lost 50% of his body fat while gaining 25.6 pounds of muscle, no steroids or illicit compounds required, and I will tell you what he did later. But while this is an extreme example, it proves an important point. It's possible. Great Scott! And in this video, I'll show you how. How it's becoming easier and easier thanks to emerging tools, some of which you can access right now, and others that are coming down the pipeline faster than you think. And today, I'm going to show you. Fat loss, especially visceral fat loss, and if you push beyond that or try to, things start to break down. You can shove that ceiling upwards. With those tools, he dropped almost 50 pounds of pure fat will improve grip strength by 40% and exercise by 20% of massively muscled cattle like the Belgian Blue, and 100% of that weight loss came from fat mass. One injection, 8 weeks, roughly 7 pounds of muscle gained and 9 pounds of fat loss. That is remarkable. All right, a quick note before we begin. Here on the YouTube channel, I'm trying my best to respect your time by providing high-yield, engaging information and hopefully doing so in a way that accesses as many people as possible without sacrificing too much nuance. That said, it doesn't mean I don't have more for you. The insights I'm going to share in this video are drawn from dozens of research papers synthesized across many articles on topics we're going to cover today, so when you're done here, if you want to go deeper down the Russian nesting dolls of curiosity, you can check out those at the global best-selling newsletter Stay Curious Metabolism. In fact, to prove it to you, throughout this video you'll notice little thumbnails popping up in the corner. Each one corresponds to a dedicated 3,000 to 5,000-word deep dive on that specific topic, all of which are linked below. But with that, let's begin. I'm going to break this discussion up into 3 parts: Natty, Next Level, and New Frontier. In the Natty section, we're going to tackle the simple question: can you white-knuckle it with Without supplementing at all. Now, Natty is not a value judgment, because there are plenty of tools that just simply help you gain an edge, some of which are accessible today like I mentioned, and that's going to be the next level section. Then we'll discuss the new frontier, tools currently in development that may change the way that you, I, or perhaps our entire species looks tomorrow. But let's begin. Part 1, Natty. I'm going to make this section relatively quick because it's just laying the foundation. It is possible to lose fat while building muscle without any supplements or pharmaceuticals. Now, how effectively you're able to do so does depend on your starting point. Are you trained or untrained? How much body fat are you carrying? What does your nutrition look like at baseline? But the general approach can be abbreviated by what I call SLAP. Not sure I deserve that. Sleep, lifting, and adequate protein. As boring as those fundamentals may sound, they're worth reviewing because it's through amplifying the biology hidden within these natural activities that we're ultimately gonna gain our edge. So let's go through them quickly. First, sleep. Sleep isn't just important for merely recovery. It's during sleep, particularly deep sleep, stages 3 and 4, that growth hormone surges. Growth hormone obviously helps support muscle growth, but it also promotes fat loss, especially visceral fat loss, the inflammatory fat that accumulates around your internal organs. Okay, sleep fast fact: many muscle-building peptides, like this one we're going to talk about later, actually work through this mechanism, and because growth hormone and deep sleep have a bidirectional relationship, they often are used to improve deep sleep. More on that here. All right, lifting. As a general rule of thumb, I suggest at least 2 to 3 resistance training sessions per week. Now, whether you prefer bodyweight exercises or heavy lifts, There really is no definitive one approach. What matters is a concept called progressive overload. Each time, you want to ask your body to do a little bit more, a little bit more, so it adapts to become stronger. To keep things exceptionally simple, and this is honestly how I approach my workouts, use relative perceived exertion, or RPE, which runs from 0 to 10. It's totally subjective. 0 is no effort, 10 is maximal effort. where afterwards you're lying on the floor questioning your life choices. See this bucket? I'm gonna be using this any second now. Now, for most people, doing the majority of their working sets in the 7 to 9 range with perhaps an occasional set to failure is an effective way to stimulate adaptation. You do need to push yourself, and if you can, it's helpful to become comfortable with discomfort. Lifting fast fact: when you work out hard, you create microscopic damage in your muscles, and your muscles respond not just by repairing it but also activating These satellite stem cells around your muscles, which donate nuclei to the main muscle fiber, allowing it to grow by providing more command centers for muscle protein synthesis. That's one of the main mechanisms behind muscle hypertrophy. Okay, adequate protein. The sweet spot is generally considered between 1.6 and 2.2 grams per kilogram of body weight. Above that, you're looking at diminishing returns and just making expensive urine. But no judgment if you occasionally demolish a 24-ounce ribeye for pleasure. I certainly do. I'm not saying more protein will be harmful per se, I'm just saying you don't need more than that. Protein fast fact: whole eggs are better for muscle building than egg whites, even when you match protein gram for gram, because the egg yolk contains nutrients and fats that help with muscle enables and muscle growth. So eat the whole egg, yolk and all, not the white. Also because egg white omelets are depressing. Anyway, if you can consistently execute on those 3 things, remember SLAP, it's entirely possible to gain muscle while losing fat without counting a single calorie or taking any exogenous compounds. To a point. This approach can be maxed out. Because if you truly lock in, you're gonna eventually hit your natural ceiling where simply trying harder, trying to white-knuckle it more becomes counterproductive. At some point, your ability to recover becomes limiting, and if you push beyond that or try to, things start to break down. Overtraining is a very real phenomenon and can negatively impact Hormones such as testosterone, cortisol, your thyroid, and even have consequences on bone health and cardiovascular health. That's why I think it's important to recognize, while the fundamentals are absolutely essential, they are not infinitely scalable. Each of us has a natural ceiling, constrained by genetics. However, you can shove that ceiling upwards with the tools we're about to discuss. And as a transition to talking about the next level, let's actually take a moment to circle back to our friend, Not me, Nicholas N. He was diagnosed with hypogonadism and low testosterone. What he did was take combination testosterone replacement therapy only to restore normal male testosterone levels while taking the GLP-1-based drug tirzepatide along with a low-carb diet. He also engaged in regular resistance training and about 10,000 steps per day. With those tools, he dropped almost 50 pounds of pure fat while gaining 26 pounds of muscle If nothing else, let's just pause to give Nicholas N., not me, an applause because that is tremendous. But that brings us to part 2, next level. Everything in this section exists today. Some of these compounds are in clinical trials, others are available through compounding pharmacies or functional medicine clinics, and some are being experimented with by biohackers and bodybuilders, those with high risk tolerance who tend to be the first humans to road test emerging biology. But let's start deep with something advanced and esoteric that you won't have heard of, and don't get afraid of the name: 5-Amino-1MQ. I know, it's a terrible name. I feel like it's if we renamed Spider-Man Bipedal Arachnoid Homo Sapiens Sapiens. Nooooo! Whoever named 5-Amino-1MQ should be fired. However, it is a very cool molecule. In fact, I have some with me here. I'll show you how to get it in one moment if you want to try it. I'm not the only member of our Stay Curious community who loves it. For example, SB says he's hitting PRs, personal records on it, and stating it's definitively one of the best compounds he's ever tried. At a high level, here's how it works. There's an enzyme in your body called NNMT, which stands for Nick Norwitz is a Major Talker. Just kidding. I mean, I am, but back to NNMT. In a lot of ways, NNMT acts like a metabolic leak. It drains your NAD system, with NAD being one of the central molecules in cellular energy metabolism. Importantly, it is one that's depleted in various metabolic diseases, ranging from aging itself to Alzheimer's disease. It's also worth noting that that enzyme NNMT, this metabolic leak, is overactive in metabolic diseases and obesity. So unfortunately, the worse your metabolic health, the faster this metabolic leak is draining you. But that's where 5-Amino-1MQ comes in. It acts as an NNMT inhibitor. It shuts down the metabolic leak, and in doing so, it helps preserve the key energy molecule NAD that instead of being bled out, allows your cells to reallocate it towards energy production, repair, and growth. Well, that's the theory. It's the underlying biology. But let's go a step beyond biochemical speculation. Because when given to mice, 5-Amino-1MQ improves strength. In fact, It does so more than exercise alone. Now, I'm not saying it will translate to humans in such a direct way, but the fact is it had a potent effect, and the effects were actually additive with exercise. 5-Amino-1MQ improved grip strength by 40% and exercise by 20%, and they stacked when done together to improve strength by 60%. And animals treated with 5-Amino-1MQ also showed reduced fat infiltration into their muscle. So less fatty muscle, higher quality muscle. And 5-Amino-1MQ has also been shown to activate muscle stem cells to help with what is effectively the basis for muscle growth, and it's been shown to help with muscle growth and repair. What's more, 5-Amino-1MQ protects against obesity when animals are fed a high-fat, high-sugar diet. I think about it as the human equivalent to an immunization against a McDonald's diet. Object: the Hamburglar. Now. There aren't yet human double-blind randomized controlled trials to show you, which honestly brings us to an uncomfortable point where I have to pause and just be honest with you. When it comes to evaluating data, we should absolutely be skeptical when we don't have rigorous controlled human trial data. However, it's also a bit of a handicap to our personal advancement if we don't entertain interventions that haven't been randomized controlled trial tested because there are so many questions we haven't answered Not because they don't have merit, but simply because we haven't invested in answering them. Science we have exists within incentive structures and business models. And 5-Amino-1MQ is an example of a compound that actually exists right now and that can help people. Admittedly, it's expensive, which is honestly why I don't take it every day. That said, I will provide a link with the discount code StayCurious below for 10% off if you want to dabble with it. No pressure. It's just since this video is about tools, I think it'd be pretty crappy of me not to provide you with some access. That said, I would encourage you to read the deeper dive before investing. But let's keep trucking. ATX304— if 5-Amino-1MQ plugs a metabolic leak, ATX304 turns up the metabolic furnace. It's actually being investigated as a diabetes drug right now, but before we get onto how it works, for a moment, can we just ask the really important question— what is with all these robot droid names? ATX304, 5-Amino-1MQ, MK-677. Anyway, let's get back to ATX304. Most diabetes drugs work by increasing insulin release, improving insulin sensitivity, or by increasing glucose excretion in some way, so peeing out glucose. But ATX304 does something very different. It activates one of the body's master regulators of energy metabolism, AMPK. This is the same protein that gets activated during fasting or ketogenic diets or exercise. Basically, AMPK is a switch that tells the body to shift away from energy storage towards energy production. That's the theory behind why researchers are exploring ATX304 and AMPK activation for diabetes. Now let's get into what actually happens starting in animals and then in humans. In one experiment, researchers placed 2 groups of mice on obesogenic diets— high-fat, high-sugar diets. And the group initially given the ATX304 is represented by the black triangles here. And what you can see is for the 15 days they got ATX304, they gained essentially no weight despite eating lots of fat and sugar and mouse junk food. But then comes the fun part. The researchers flipped the groups, now giving the ATX304 to the mice represented by the white triangles, and you can see what happened. A complete weight inversion effect. The animals that started taking the ATX-304 rapidly lost weight, while the animals that were taken off of it and given the obesogenic diet gained weight. Then, around day 56, the groups were switched again. Like the ultimate weight yo-yo effect. But that's not even the best part. Calorie intake was higher in the groups losing weight at any given time point. In other words, ATX-304 caused weight loss despite no reduction and in some cases increases in food and calorie intake. And in another animal study, 32 days of ATX-304 treatment led to a 21% reduction in body weight and 100% of that weight loss came from fat mass. All of it. No loss of lean mass, not a gram. And while there are not yet human trials specifically targeting body composition, ATX-304 has successfully completed phase 2 human clinical trials and appears to be well tolerated with early documented benefits on blood sugar and vascular health. This is an exciting compound that's being actively investigated in human trials, and yeah, you can get your hands on it, more information below, but I want to move on to an entirely different category: the muscle peptides. This is also a different delivery system. Nothing we've talked about thus far requires injections. But these muscle peptides do, and they generally act on the body's growth hormone system. Now, as a quick primer and relevant background, the brain releases something called growth hormone-releasing hormone, which does what it says it does. It causes the pituitary gland to release growth hormone, and then growth hormone triggers a variety of downstream effects including muscle protein synthesis and visceral fat breakdown. In the deep dive, I go over many of the different muscle-building peptides including CJC-1295, ipamorelin, sermorelin, tesamorelin, MK-677, and the rest, Huh, huh, huh. Let me focus on what is probably the most popular combination in this space called CJC-1295 and ipamorelin. If you Google it, you're gonna see it everywhere. And the basic idea is the CJC-1295 component acts like pressing the gas pedal on the growth hormone system. It's a GHRH, growth hormone-releasing hormone analog, meaning it amplifies the body's natural growth hormone signaling. It does not replace growth hormone. It is not growth hormone. This is not the same as administering human growth hormone. Rather, it's encouraging your pituitary to release growth hormone in larger but still physiologic pulses. And the other component, ipamorelin, works through a complementary mechanism, in part by helping take the brakes off the system, a hormone called somatostatin, but I've already overloaded your brain with fancy words. You don't need to know that. The simple way to think about it is CJC-1295 presses the gas on muscle growth and ipamorelin takes the Again, more details regarding actual protocols in the deep dive below, but because this is a prescription compound and when obtained through the proper channels requires physician oversight, I'm not going to give you the exact dosing protocols here on YouTube. And as a quick aside, if you're interested, I've now disclosed who my personal peptide doctors are and how to access them. More information on that below. But you should know that these compounds do have profound biological effects. I've personally seen people gain 10 pounds of muscle while simultaneously losing fat over the course of a few months. I also thought I'd toss in, because I just got permission to share it, these are the before and after photos of NOHO Labs CEO and co-founder Matt Mazzzeo. Matt is a character, in the best way, he's an awesome guy, but his company grew out of a series of self-experiments with peptides that, by his account, transformed his life, and not just in the physical domain. Now, he's been following my work for a while and was a fan, which is why he reached out to me and how our clinical partnership really began, but I mean, come on, look at that transformation. And that is a year, 2025 to 2026. It is wild. But what excites me the most isn't Matt's result itself, but the possibility of using tools at our disposal today to make outcomes like that less the outlier than the norm. On a related note, I should mention Tessa Morellin. Tesamorelin acts similarly to CJC-1295 in that it stimulates the body's production of growth hormone, however in some ways it's even more potent, and more rigorously studied, particularly for reducing visceral fat. Interestingly, many of the original studies focused on patients with HIV. Weird, right? You didn't see that coming, did you? Well, in simple terms, some HIV medications can cause visceral fat accumulation, making this population relevant for studying therapeutics that target visceral fat. Anyway, in multiple double-blinded randomized placebo-controlled trials, including studies published in top journals like the New England Journal of Medicine, testosterone consistently reduces visceral fat relative to a placebo, often on the order of 20%, which is remarkable. That is not a subtle effect, it is a sledgehammer. And again, this compound is not one to use casually or flippantly, but it works, and it's an FDA-approved tool at least for specific populations. But let's get on to part 3, the new frontier, the most powerful set of tools which aren't available to you or me yet, but are currently in development in human clinical trials. Now, the foundational insight behind these class of molecules comes from the fact that biology actually places a brake on muscle growth. And evolutionarily this makes sense because muscle is energetically expensive. In an environment where food was scarce and energy was precious, you didn't want too much muscle, it would just waste away energy. Obviously the situation is different today, both in terms of our food environment and our body composition goals. Anyway, not only are those biological brakes on muscle growth still in place, but our bodies actually have redundant braking systems as backup, including pathways involving myostatin and activin-A. You don't need to know those terms, the idea is just they're complementary redundant systems for preventing too much muscle growth. Interestingly though, Some animals, and even a few humans, are born with deficiencies in these muscle brake systems, leading to what is known as a double muscle phenotype. Think about massively muscled cattle like the Belgian Blue, or extraordinarily built dogs like the Bully Whippets, and a handful of genetically blessed humans who carry remarkable amounts of muscle with little to no effort. I don't even exercise. So the logic Seems obvious, right? What happens if you release the brakes and let muscles grow? Well, things get pretty crazy. For example, in a recent study published in Nature Communications, researchers treated monkeys with molecules that blocked these myostatin and activin-A signaling pathways, and the result was a 30% reduction in fat mass while gaining 10% lean mass at the same time. And it gets more interesting because there's even substantial interest in combining these muscle-building therapies with modern weight loss drugs like GLP-1 receptor agonists, drugs like Ozempic and Wegovy, and at least in monkeys, when researchers combined these 2 approaches, fat mass decreased by 50% while lean mass still increased by 6%, which is, pardon the monkey pun, absolutely cuckoo bananas. And these therapies are already being explored in humans. In one randomized placebo-controlled human trial, a single dose of one such therapy produced 6.6 pounds of lean mass gain with 8.8 pounds of fat mass loss over 8 weeks. Think about that for a moment. One injection, 8 weeks, roughly 7 pounds of muscle gained and 9 pounds of fat loss. That is... Crazy. Remarkable. Now there were some side effects admittedly, including headaches, nausea, and urinary tract infections, so this isn't ready for prime time to be rolled out yet, but it is coming, it is already moving swiftly through human clinical trials. Now that's bringing us to the end, but before we wrap up, I need to ask the big question we haven't actually asked, maybe I should have started the video with this: is this desirable? Now objectively as a population, we tend to be undermuscled and overfat. So there's clearly a health need for improving body composition at a population scale. However, to what extreme? Personally, I don't think our cultural ideals for male or female physiques are necessarily ideal for health, and I think we need to keep that in mind. What does healthy actually look like? It's a much more nuanced question, and the reality is that everybody's version of healthy looks differently on their own bodies. So as much as I find tools like this exciting and I love exploring the science with you, This isn't the sort of video where I'm trying to advocate that you go out, run out, throw the entire kitchen sink at yourself whether by swallowing it or injecting it. I have experimented with and will continue to experiment with some of these compounds because I find it scientifically fascinating. My priority is just remaining healthy and functional, and right now my body can pretty much do everything I want it to do mostly with the fundamentals. For now, currently I have the advantage of youth, but in 10 to 20 years I will lean more heavily on these tools. as needed. And that is what this is about— tools and agency. Empowerment. Because at the end of the day, what I'm offering you is not a prescription for what you should do, but what you can do. And what you can do now, if you enjoyed this video, is please subscribe and hit like. It really helps this channel do like a muscle on a myostatin inhibitor and grow. Stay curious. Thanks, Thomas.