5 Peptides You’ve Probably Heard Of, Explained
Semaglutide, NAD+, GHK-Cu, and a few other names keep showing up in your feed. Here's what each one actually is, in plain language, and what Rex currently offers if you're curious.
By The Astute Poodle · Published 2026-08-19T18:52:00.000Z
Semaglutide. NAD+. GHK-Cu. If you've spent any time on social media or just scrolling news headlines about weight loss and wellness, you've probably run into at least one of these names, whether or not you knew exactly what it does. Here are five names you've probably already heard of, explained in plain language, including one that isn't technically a peptide but gets grouped in anyway, plus what Rex currently offers if you're curious about any of them.
A quick-reference summary of the five peptides covered in this article, including which treatment category each one falls under. NAD+ is included for context, though it's technically a coenzyme rather than a peptide.
1. Semaglutide
You've probably heard of semaglutide because it's the active ingredient behind brand-name medications like Ozempic and Wegovy, two of the most talked-about weight-loss drugs of the past few years.
Semaglutide is a GLP-1 receptor agonist. In plain terms, it mimics a hormone your body already makes after eating, which plays a role in appetite, blood sugar, and how full you feel after a meal.
Rex, once we are live, will offer compounded semaglutide, prepared by a licensed pharmacy partner using the same active ingredient, after a licensed provider determines it's appropriate for you. Compounded semaglutide isn't the same as an FDA-approved product like Ozempic or Wegovy, since it isn't reviewed and approved by the FDA as a finished medication, but it's built on the same active ingredient under a provider's care.
2. Tirzepatide
Tirzepatide is semaglutide's newer, dual-action relative. It's the active ingredient behind Mounjaro and Zepbound, and it targets two hormone pathways, GLP-1 and GIP, instead of one.
That dual mechanism is part of why tirzepatide comes up as a stronger option for some people, though whether it's the better fit depends on your own health history and goals, which is exactly what a provider evaluation is for.
Rex will offer compounded tirzepatide the same way we offer compounded semaglutide: prepared by our pharmacy partner, prescribed only after a licensed provider reviews your intake.
3. NAD+
NAD+ isn't technically a peptide. It's a coenzyme, a different kind of molecule your cells rely on for basic energy production. We're including it here because it's commonly offered alongside peptide-focused care, and it's one of the names people ask about most.
NAD+ levels naturally decline with age, which is a big part of why it comes up so often in energy and longevity conversations. Rex will offer NAD+ via an injection or as tablets, depending on what a provider recommends.
4. GHK-Cu
GHK-Cu is a copper peptide your body produces naturally, and it's one of the more established names in skin and hair health circles.
It's been studied for its role in supporting skin structure, collagen, and wound healing, which is why you'll see it in topical treatments and skin-focused formulations. Rex will offer a GHK-Cu anti-aging cream or tablets
5. Selank
Selank is a synthetic peptide, developed in Russia, that comes up most often in conversations about anxiety and mental focus.
Research on Selank includes both animal studies and smaller human trials, most conducted outside the United States, and it hasn't gone through the kind of large, placebo-controlled trials that FDA-approved anxiety medications have. It's also not FDA-approved. If you're curious about it, that's exactly the kind of thing to bring up with a licensed provider rather than deciding on your own based on what you've read online.
These five names get thrown around a lot, sometimes accurately, sometimes not. If you want the fuller picture of how peptides work in general, What Are Peptides? is a good place to start.
For more on Rex's planned programs and launch updates, visit the Rex homepage.
