In this educational YouTube video, Dr. Ashley Frazee, a direct primary‑care physician, provides a non‑prescriptive, science‑focused overview of injectable peptides that are popularly used to enhance muscle growth and fat loss. She begins by framing her responsibility to understand these compounds beyond the hype found online, then explains the underlying physiology of growth hormone (GH) and insulin‑like growth factor‑1 (IGF‑1) and how they drive muscle hypertrophy. The video systematically reviews the main classes of peptides: growth‑hormone‑releasing‑hormone (GHRH) analogues (sermorelin, ModGRF/CJC‑1295 without DAC, CJC‑1295 with DAC, tesamorelin), describing their molecular basis, half‑life, FDA status, and typical user profiles. Next, she discusses growth‑hormone‑releasing peptides (GHRPs) such as ipamorelin, GHRP‑2, GHRP‑6, and hexarelin, emphasizing how they amplify GH pulse amplitude and why ipamorelin is preferred for its cleaner hormonal profile. The latter part covers higher‑risk, research‑only compounds—IGF‑LR3 and follistatin—detailing their mechanisms (direct IGF‑1 activity, myostatin inhibition), potential performance benefits, and notable safety concerns (insulin resistance, organ growth, limited human data). Throughout, Dr. Frazee highlights known adverse effects (water retention, joint pain, insulin resistance, possible tumor promotion) and stresses the paucity of robust clinical data for many peptides. She concludes with a clear disclaimer that she is not providing medical advice or protocols, urging viewers to weigh risks, understand the science, and consider safety before any self‑administration.
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Injectable peptides are basically the new trend that nobody ever told your doctor about. And honestly, I get it. If you could jab yourself with 5 magical research chemicals and wake up with muscles, that's an easy sell, isn't it? Listen, I'm a real-life doctor, and despite the gray zone that peptides can be in, I still like understanding the research on them because I feel a responsibility to know more about them than the gym bros on the internet. And a lot of my patients want to feel strong, lean, capable, and you probably do too. So in this video, I'm going to walk you through the actual science behind the most popular peptides, the ones that people use for muscle building. And I'm going to talk about the research here for the sake of science, not for medical advice. This is not that. I'm just a random doctor on the internet talking about things that are being researched. By the end of this video, you'll understand how growth hormone and the hormone IGF-1 actually build muscle. Simply explained. The kind of good, better, and advanced peptide stacks. Why certain peptides are stacked together like CJC-1295 and ipamorelin. What some of the more advanced peptides like IGF-LR3 and follistatin do. And the actual risks of using peptides that get really glossed over online. So all of these peptides look and sound almost identical on paper. Sermorelin, ipamorelin, hexarelin, tesamorelin. And then there's ModGRF and IGF-LR3, CJC-1295. It sounds like somebody named them during a power outage. So let me explain this as simply as I can. To understand how peptides can theoretically or actually amplify muscle growth, you have to understand the science between growth hormone and IGF-1. You can think of the pituitary, the little gland that lives at the base of your brain, as like the DJ at a party. Every growth hormone pulse that it puts out is kind of like a track that the DJ DJ is playing. And each time growth hormone surges, it sends a message to the liver to produce something called IGF-1. And that's the hormone that actually works to build muscle, repair tissue, and increase strength. When you're young, the DJ is on fire. Growth hormone pulses all night long. And then every decade after 30, the DJ gets kind of tired, the songs get a little bit softer and fade away. Now peptides do not replace growth hormone. That's not what they are. They just wake the DJ back up and the party gets thumping again. Now let's go through the peptides that actually do that. The growth hormone-releasing hormone peptides: Sermorelin, ModGFR, or CJC-1295, CJC-1295 without a DAC, or a drug affinity complex, and Tesamorelin. These are peptides that basically walk into the DJ booth and say, Hey DJ, play that song. The pituitary then wakes up and starts playing those bopping songs again. It releases those pulses of growth hormone. And I'm going to walk you through this from shortest to longest half-life of these peptides. That's why they differ. Let's start with serramorelin, the OG of growth hormone-releasing hormone peptides. It has the shortest half-life out of all the, the GHRH peptides, and it's a modified version of the first 29 amino acids of growth hormone releasing hormone. A good analogy is to think of it as like a bright sparkler at a party. It's got a really bright spark and then it fades away pretty quickly. And in the body, it's broken down by something called DPP-4. It's an enzyme that gets rid of it. Sermorelin is able to mimic your natural growth hormone pulses. It's really great for sleep. It's mild, it's safe, and it's actually prescribable. Number 2, ModGRF. This is what people call CJC- $1,295 with no drug affinity complex, and I'll get to that in a minute. The half-life of this peptide is about 30 minutes, so it stays in the body a little bit longer. It's like a mega sparkler that you can buy that just burns for a little bit longer. Researchers made it and swapped around some of the amino acids in order for it to be able to resist that enzyme, that DPP-4, that breaks it down. And then there's CJC-1295 with the drug affinity complex. This drug affinity complex binds to albumin, which is an abundant protein in the bloodstream. And allows it to hang around much, much longer, creating a non-pulsatile release of growth hormone. And we call this a growth hormone bleed, meaning it's just constantly letting it out. It's got extremely long activity from like 6 to 8 days. It's like if you took that sparkler and glued it to a candle to allow it to just keep burning for a week. And then there's Tesamorelin. It's really stable. Tesamorelin hangs around in the body for about 30 minutes, but its effects last for almost 24 hours. Meaning the growth hormone elevation that it produces lasts about that long. Something that's interesting to me is that sermorelin and CJC-1295 are made up of the first 29 amino acids of growth hormone-releasing hormone. That's why you'll see the numbers 1 through 29 if you read the research on these compounds. Tesamorelin is actually the full 44 amino acid sequence of growth hormone-releasing hormone, but it's modified with a fatty acid in order to keep it Stable in the body. The FDA approved this peptide for use in HIV-associated lipodystrophy, meaning that they used to give HIV patients certain medications that could build up visceral fat on their bodies. And so they used tesamorelin as daily injections to get that fat to burn off. And so tesamorelin has become very popular as a visceral fat burner. And so in the real world, what you'll see is a lot of people trying to put on muscle are choosing to inject CJC-1295. A lot of people who want a cleaner, more physiologic effect are using something like Sermorelin, or they'll step into the peptide world using Sermorelin first. And then serious people who really want gains and leaning out at the same time, if you can even do that, use Tesamorelin. And there is a downside to that because Tesamorelin, we have a lot of human data on it and using it consistently can lead to more side effects than the others theoretically can. Okay. So those are peptides that give you that solo growth hormone signal. But you didn't come to this video to talk about one kind of peptide, did you? You came to learn about stat. So let's go there. All right. The big question is, why does everyone combine CJC-1295 with ipamorelin or tesamorelin with ipamorelin? Well, the logic here is actually pretty simple. So growth hormone releasing hormone allows that pulsatile release of growth hormone. And then there's growth hormone releasing peptides like ipamorelin that amplify the message. They increase the Amplitude of those growth hormone pulses. And increased frequency plus amplitude equals a lot of synergy. So let's get into the science of ipamorelin, the growth hormone-releasing peptides. If growth hormone-releasing hormone peptides wake up the DJ in the booth, ipamorelin says, turn up the sound. Kind of like the hype man, it runs to the DJ and says, turn it up, man. And so the DJ will drop like a more potent, more bumping song. So basically it triggers the pituitary to release more of that growth hormone that it was prompted to do with the growth hormone releasing hormone peptides. And all of this also quiets another hormone called somatostatin, which basically reduces the noise and makes the signal a lot cleaner. And ipamorelin in particular is able to increase the volume on the track without increasing cortisol and prolactin, which some of the other growth hormone releasing peptides Actually do. So that's why ipamorelin is kind of the preferred one out of the bunch. So again, this is why you'll see bodybuilders pairing CJC-1295 or tesamorelin with ipamorelin. And then the other growth hormone releasing peptides like GHRP-2, GHRP-6, hexarelin, they all do the same thing as well, just to varying degrees. And they're also bumping up cortisol, prolactin, and hunger. So you can see how ipamorelin is just a cleaner amplifier. But wait, there's more. And the following are not beginner peptides, as if I'm talking like the others were. But these next ones I'm talking about, they're more high-risk, high-reward. And this is where people get in trouble chasing really rapid gains with limited safety data to back it up. Let's hit the 2 big ones out there: IGF-LR3 and Follistatin. IGF-LR3 is a synthetic version of the hormone IGF-1 that's designed to be more stable or long-acting and more potent. Now researchers actually made this peptide in order to be able to research the effects of IGF-1 because IGF-1 is not very stable. It doesn't stick around long and it's bound up to certain proteins, which made it difficult to study. Hence came along IGF-LR3 and somewhere in there people started using it on their own bodies. So IGF-LR3 is designed to just skip the whole growth hormone pathway and goes straight to the tissues and sticks around and does it in a very potent way. So the pros are increased strength, increased muscle mass, Muscle mass, increased recovery, more fat loss, but it comes with risks of lowering your blood sugar, increasing insulin resistance, causing a little bit of anxiety, potentially increasing visceral organ growth and causing that kind of like turtle shell look to very muscular people. Then there's follistatin. This is a myostatin brake releaser. So you can think of this peptide as having the ability to cut the brakes on muscle growth. You see, we all have something called myostatin that puts a limiter on your muscle growth. And when you take that brake off, your muscles just get huge. And that's what follistatin is designed to do. But you have to keep in mind that even though you have really big muscles, they don't always necessarily come with strength gains. It reminds me of like Jersey Shore where they kind of looked all big and muscly, but you weren't even sure if they actually had the strength behind it. I'm sure that's not true, but it's a good analogy. And it sounds amazing, but in reality it's kind of hard to dose. You get really inconsistent results. You got big old muscles, but you can only lift like I don't know, a chicken or something. I don't know why chicken. I'm just gonna stick with it. So I'm not sharing all of these things for you to run to the nearest peptide website, load up your cart, and then Google a discount code. You need to know the potential risk of putting these things into your body, especially since they're not made for you to put into your body. But if you're gonna do it anyway, if you push a growth hormone pathway too much and too consistently, just know that there are downsides to that. And we don't have a lot of human data on most peptides, but these ones actually do come with a lot of human data. Sermorelin was actually FDA approved for a long time, but the company that made it didn't make any profit. And so that's why I'm still able to prescribe it if a compounding pharmacy will make it for you. Then there's CJC-1295, also has a lot of human data. Why it's not allowed on the bulk drug list is another story. Tesamorelin has a lot of human data because it's FDA approved for that one specific reason. Ipamorelin and most of the GHRP peptides also have a lot of human data behind them as well. Things like IGF-LR3 and follistatin, they do not have much human data at all, and that's why they're riskier and considered way less safe— strictly research chemicals. And out of all of those, the one that we have the most research on side effects, or the one that has the most side effects that we know of for sure, is tesamorelin, which shows some documented side effects of water retention, joint stiffness and pain, and insulin resistance at really high doses, and things like carpal tunnel. And I have a whole video on the risk of these particular peptides and cancer. Please watch that if you haven't. But I'll just say this: if you have an active cancer or tumor, or you are very prone to them, please do not stimulate your growth hormone pathways, full stop. So I hope that was fun for you. You know, peptides aren't magic, but they're very cool. They're amplifiers of biology. I'm not giving protocols here. I'm not encouraging use. But I think it's my responsibility as a physician to understand what these things are doing, because a lot of people are just Putting them in their bodies anyway. And maybe if you understand it better, you'll be able to think twice about it. Or if you're going to do it anyway, you'll at least be safe about it. I'm Dr. Ashley Frazee. I run a direct primary care clinic in Mesa, Arizona. I'm just a doctor on the internet with a camera, and I drive to know more about things that interest you. If you like this video, please hit like for me, subscribe to my channel, and, and you have the best day.
