In this 2025 YouTube monologue, board‑certified primary‑care physician Dr. Ashley Frazee ("Ashley F") explains what peptides are, how they function as short amino‑acid chains that act like keys fitting into cellular receptors, and why she believes they can "reboot" human physiology. After a disclaimer that she is not providing medical advice, she categorizes a wide array of peptide classes, describing their molecular targets, reported pre‑clinical or clinical effects, and how they might be combined with lifestyle interventions (fasting, cold exposure, exercise). The video covers: (1) metabolic/weight‑loss peptides that mimic gut hormones (semaglutide, tirzepatide, cagrilintide, retatrutide) and a non‑peptide insulin‑sensitizer (5‑Amino‑1MQ); (2) mitochondrial‑supporting agents (MOTS‑c, SS31) and an exercise‑mimetic (SLUPP‑332); (3) tissue‑repair peptides (BPC‑157, TB‑500); (4) growth‑hormone‑related peptides (CJC‑1295, Sermorelin, Tesamorelin, ipamorelin, GHRPs, IGF‑LR3, follistatin, AOD‑9604); (5) neuroactive/nootropic agents (tesofensine, Semax, Selank, Dihexa, cerebrolysin); (6) cosmetic peptides (collagen‑derived fragments, GHK‑Cu, SNAP‑8); (7) longevity/immune‑modulating peptides (Epithelin, KPV, thymosin α‑1, FOXO4‑DRI). She frames each class as a signaling tool that can restore insulin sensitivity, mitochondrial function, tissue repair, cognition, or skin health, emphasizing that peptides are not merely performance‑enhancing drugs but potential “software updates” for the body. The video ends with a brief promotion of her direct‑primary‑care clinic and a call to like/subscribe.
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I'm a board-certified primary care doctor, and I work directly for my patients, which means that I have time to focus on things like actually fixing people versus putting Band-Aids on things. Improving the way that your body works is something that I'm really on board with, and the more research I do on peptides, the more amazing things I see. Watch this video and you'll see why peptides aren't just about muscle gain and fat loss. They're about repairing the body at its core, and that's what makes them so powerful. That being said, do not take anything I say on here as medical advice. I'm just a on YouTube talking about research and experimental things here only. I am not your doctor. So if you don't already know what peptides are, they are literally chains of amino acids, the same stuff that proteins are made out of. And most of them are designed to fit right into receptors in the body to create some sort of message or signal. Plain and simple, it's like fitting a key into a lock. They usually come as a white powder like this, and most of the time they're reconstituted with something like bacteriostatic water, and the water mixes with the powder like this. Swirl it around, you've got yourself an injectable peptide. Now that's not actually how it's done in a sterile environment, but now you know what they look like. You can also think of peptides like text messages between cells. Short, specific, powerful messages. You see, you don't always need to override your biology with medications. Rather, sometimes you can just send the right signals. Signals that teach the body to repair itself, to sleep better, to get stronger, or shut down the noise that makes you hungry all the time. And speaking of, there are some peptides that do that. Let me start by describing the most popular weight loss peptides: semaglutide, tirzepatide, cagrilintide, and retatrutide. These peptides basically mimic your own gut hormones: GLP-1, GIP, glucagon, and amylin. They basically talk directly to the brain and the pancreas to restore metabolic rhythms, basically allowing for insulin resistance to die down. And you may have heard me say this before, but I think that insulin resistance Insulin is the root of the majority of obesity and disease. Fix insulin resistance, fix obesity, fix a lot of the world's health problems. And beyond peptides, there are other molecules being researched that work deeper than insulin signaling. Take 5-Amino-1MQ, for example, which increases NAD and insulin sensitivity by blocking an enzyme that slows down metabolism. I have another video on non-peptides if you wanna learn more about that. I mean, this is not just appetite suppression with pills. This is a total system reboot. You're not just muting down a symptom. that causes obesity and overeating. With peptides, you're actually rewriting the software that manages appetite and insulin signaling. All right, I'm going to switch gears on you and talk about my favorite thing lately, mitochondria, the source of energy and endurance. I'm a softie for this stuff because I like to stay active. So energy and endurance are a big deal to me. So your mitochondria, they're like the batteries in all of your cells. They're what produces energy. And when they go bad, which they tend to do with aging and inflammation, oxidative stress, Everything slows down and you get things like chronic fatigue, inability to sleep, inability to lose weight, all of the above. Okay, but there are 2 peptides that basically boost your mitochondrial health. You can either get your body to make more mitochondria with MOTS-c or stabilize the mitochondria that you already have with SS31. SS31 has been studied in heart failure, kidney disease. It's even FDA approved for a mitochondrial disease called Barth syndrome. MOTS-c is a mitochondrial peptide that already exists in our bodies that turns on the signaling that allows you to make more mitochondria and burn more fatty acids. At least that's what the research in mice shows. These are amazing peptides. And a non-peptide that has less research behind it but is very promising is SLUPP-332, which is basically being called exercise in a bottle, and rightfully so. I have a video comparing all 3 of those if you want to learn more. Guys, when you combine things like this with things like fasting, cold exposure, exercise, you're basically signaling your body to create More energy from the inside out, to be more efficient, to be better. All right, let's talk about the peptides that get the most hype about being peptides. Like when a bro comes to me and says, let's talk about peptides, what can you tell me? They're mainly talking about these ones. When it comes to recovery, tissue repair, injury repair, nothing gets more hype than BPC-157 and TB-500. BPC-157, it's a fragment of a peptide that's made in your stomach naturally that's thought to protect the lining of the gut due to high cellular turnover in the stomach and the gut. It basically accelerates healing by promoting angiogenesis, or blood flow, and collagen rebuilding. TB-500 is found in animal studies in tissues that are trying to repair themselves. Basically, it's thought to help cells migrate and reorganize after injury. And when you combine them together, it's like sending a construction crew to an injury. There's lots of animal research on these 2 compounds, not a lot of human data, but there are a lot of human stories out there claiming that these compounds have been pretty life-changing. Moving on to body composition. Okay, in the body composition space, these are also very popular peptides that mainly bros in the weightlifting world want to talk about with me. When you hear people talk about CJC-1295 or Sermorelin or Tesamorelin, these are designed to boost natural growth hormone. Boosting growth hormone, especially combined with weight training and good sleep, allows bodies to gain more strength and muscle, burn more fat, and get better sleep and skin quality. What's the difference between all of these? Basically, CJC-1295 works longer and is a really popular combination with something called ipamorelin, which I'll talk about. Sermorelin is more short-acting and considered a gentler, more physiologic peptide. Tesamorelin also is longer acting but has incredible fat-burning potential. It's actually FDA approved for something called HIV lipodystrophy. Basically, if somebody with HIV was taking a medication that put fat around their organs, they use tesamorelin to burn that fat back off. Ipamorelin GHRP-2, GHRP-6, hexarelin. These all also boost up growth hormone, though through the ghrelin pathway. Ghrelin is a hormone that makes you hungry. Ipamorelin is the most commonly used by people who are basically doing research on their own bodies because it tends to not boost hunger or cortisol as much as the others do. Now, physiologically downstream in the hormone pathway of ghrelin and growth hormone is IGF-1. And if you want to jump straight to boosting IGF-1, there's a peptide called IGF-LR3, which is a long-acting form of IGF-1. And if you want to know the research on just muscular hypertrophy, look into something called follistatin. Follistatin basically takes the brakes off of muscular growth. And if you want to look into the fat loss benefits of growth hormone, you could look into the research on AOD-9604. Okay, that was a lot. Let's take a pause. Okay, good to go. All right, peptides don't just rebuild muscles. According to the research, they can potentially rebuild neurochemistry. Tesofensine, for example, is a norepinephrine-serotonin-dopamine reuptake inhibitor that's been shown in research to reduce appetite while boosting mood and satisfaction. It's kind of like combining the metabolic effects of the GLP-1s— semaglutide, tirzepatide, retatrutide— with the mental energy of a stimulant like phentermine, except it works through your brain's reward circuitry. There's also Semax. Research shows that Semax, or Semax, I don't know how you say this one actually. Basically, this is a fragment of ACTH, and research shows that it works with BDNF, or brain-derived neurotrophic factor, neurotrophic factor, and dopamine and serotonin systems, contributing to improved memory and focus. And Selank, there's really great research showing that Selank can be used to lessen anxiety. Dihexa is a nootropic peptide that, according to research in animals, helps form new neural connections. It's very popular for its ability to potentially improve focus and clarity. It's also considered a highly promising peptide for cognitive decline. There's cerebrolysin. This is a blend of peptides that is being researched for recovery from things like stroke and dementia. It's literally designed to help neurons regrow and reconnect. Imagine medicine helping repair your body's communication signaling pathways versus just muting things. That's where we're headed. All right, let's talk about skin, hair, and nails. Everybody knows about collagen as a beauty supplement, right? When you digest collagen, you're actually releasing short peptides that tell your body to make more collagen. It's basically primitive peptide therapy. GHK-Copper is a peptide that works with the same idea, just magnified and targeted. It's a copper-binding tripeptide found naturally in your plasma that safely delivers copper to cells. Which tells them to rebuild and even stimulate new hair follicle growth. Then there's SNAP-8. This is an octapeptide that relaxes facial muscle tension by blocking neurotransmitter release. Think of it as like the over-the-counter cousin to Botox. It's been shown to soften expression lines over time. This is a perfect example of how even cosmetic peptides use the same signaling pathways as therapeutic ones. And these aren't just cosmetics, they're cellular tune-ups. Lastly, let's just talk about some cellular longevity here. Epithelin. This is a peptide that supports circadian rhythm and melatonin release, helping you sleep like your younger self used to. According to research, it can actually lengthen telomeres, basically an anti-aging peptide. KPV. As we age, basically damaged cells can pile up and cause dysfunction in the body, oxidative stress and whatnot. And basically the immune system can start to misfire. KPV, which is a naturally occurring tripeptide fragment of the hormone alpha MSH, helps suppress inflammation at the cellular and gut level. It's basically being researched to help flip the body back into repair and recovery mode instead of defense mode. Thymosin alpha-1 basically strengthens immune coordination. FOXO4 DRI basically helps clear out old damaged cells that are supposed to die off, but they don't. You know, that's not just anti-aging, that's like Cellular housekeeping. So yeah, peptides are popular for helping you get stronger, leaner, smarter, but at their core, they basically help your body remember how to heal itself. And that's the future of medicine. I'm Dr. Ashley Frazee. I run a direct primary care clinic in Mesa, Arizona. It's basically where I don't take insurance. My patients just pay me directly, so we have the freedom to talk about things like this. I appreciate you watching. If you like this video, please hit like for me, subscribe to my channel, and I'll try to keep making videos that are relevant to you. I hope you have the best day.
