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What Are Peptides? GLP-1s, Peptide Therapy, and What You Should Know in 2026

Ryan · February 26, 2026

*This article is general education only. Nothing here is medical advice, a treatment recommendation, or a dosing plan. Peptides include prescription medications — always consult a licensed clinician before starting any peptide therapy.*

The science: Liposomal encapsulation, explained

Manna Editorial Team

Peptides are having a moment. Here's what's actually going on.

You’ve almost certainly heard the word. Ozempic is on the news. Mounjaro is the subject of half the podcasts in your feed. Your gym buddy is talking about BPC-157. Your doctor’s office just added a “peptide therapy” section to its website. And somewhere in between, you’re trying to figure out what a peptide actually is — and whether any of this applies to you.
The honest answer is that “peptide” is a broad term that covers a wide range of molecules, from blockbuster GLP-1 drugs prescribed to millions to research-focused compounds that clinicians are using in wellness and longevity contexts. Not all peptides are the same. Not all of them are prescription drugs. And the process of accessing and using them varies significantly depending on which category you’re talking about.
This guide is a straightforward orientation: what peptides are, the main categories people are using right now, how they’re typically prescribed and accessed, and what the practical preparation process looks like. If you’re already past this point and want the step-by-step reconstitution walkthrough, go straight to Peptide Injections: What Happens After You Get a Prescription.

What is a peptide, exactly?

At a chemical level, a peptide is a short chain of amino acids — the same building blocks that make up proteins. The technical distinction is length: fewer than 50 amino acids and it’s generally called a peptide; more than that and it’s a protein. In practice, the line is blurry and doesn’t matter much for understanding why they’re used therapeutically.

What matters is that many of the body’s own signaling molecules are peptides. Insulin is a peptide. So are many hormones and growth factors. The reason researchers and clinicians are interested in synthetic peptides is the same reason the body uses them naturally: they can act as precise signals, telling specific cells or systems to do specific things.

Different peptides target different pathways. Some are designed to mimic a hormone. Some amplify a signal the body already sends. Some are engineered to slow an existing process — like appetite. The specificity is the point.

The GLP-1 class: semaglutide, tirzepatide, and the weight loss wave

The peptides most people have heard of belong to a class called **GLP-1 receptor agonists** (glucagon-like peptide-1). These are the ones behind Ozempic, Wegovy, Mounjaro, and Zepbound — drugs that became famous for their weight loss effects but were originally developed for type 2 diabetes management.

**Semaglutide** (the active ingredient in Ozempic and Wegovy) works by mimicking a naturally occurring hormone that signals satiety — the feeling of fullness. It slows gastric emptying and reduces appetite, leading to significant weight loss in clinical trials. It’s a once-weekly subcutaneous injection.

**Tirzepatide** (Mounjaro, Zepbound) is a newer dual-agonist that targets both GLP-1 and GIP receptors. It has shown even stronger weight loss results in trials than semaglutide and is increasingly prescribed for weight management in addition to diabetes.

Both are **FDA-approved prescription medications**, and the version you get from a licensed physician is the commercial brand. The explosion in demand, combined with drug shortages, also created a large market for compounded versions — manufactured by compounding pharmacies under physician supervision. These are not FDA-approved in the same way commercial drugs are, which is an important distinction that any clinician prescribing them should explain clearly.

**For anyone considering GLP-1 therapy:** this is a category where a licensed prescriber matters enormously. The clinical landscape changes quickly. Dosing protocols vary. The difference between a well-run telehealth clinic and a provider cutting corners is not always visible from the outside. Ask questions.

Beyond GLP-1s: other peptide categories in use

**Repair and recovery peptides**

Compounds like BPC-157 (Body Protection Compound) and TB-500 are studied for their potential roles in tissue repair, inflammation, and recovery. Neither is FDA-approved for human use as a drug, but both are used in clinical and research contexts. They’re typically sourced through compounding pharmacies under a clinician’s order.

**Growth hormone secretagogues**

Peptides like Sermorelin, Ipamorelin, and CJC-1295 stimulate the pituitary gland to release growth hormone. They’re used in anti-aging and longevity medicine contexts. These are prescription compounds requiring physician oversight.

**Skin and collagen peptides**

A separate, much more mainstream category includes topical or oral peptides — like GHK-Cu (copper peptide), which appears in skincare for its potential role in collagen synthesis. These are generally not injected and are available in cosmetic and supplement form.

**Metabolic peptides**

AOD-9604 is a fragment of the growth hormone molecule that’s been studied for fat metabolism effects. MOTS-c is a mitochondria-derived peptide being researched for metabolic benefits. These are largely in earlier research stages for human therapeutic use.

The common thread across the injectable categories: most are obtained through a **clinician + compounding pharmacy** pipeline, and most arrive as a **lyophilized (freeze-dried) powder** that the patient reconstitutes at home. This is the practical process that the rest of this cluster covers.

How people actually access peptides today

Many of the same clinics that prescribe GLP-1s also offer other peptides — sermorelin, BPC-157, and others — through a similar model: evaluation → prescription → compounded product → patient self-administration.

**Medical spas and wellness clinics**

A growing number of medical spas and longevity clinics offer peptide therapy as part of broader wellness programs. The regulatory and quality standards vary significantly by location and operator. The physician oversight model still applies — a prescriber must be involved — but the degree of individualized care varies.

**What arrives from a compounding pharmacy**

For most injectable peptides (outside of commercial GLP-1 brand products), what you receive is typically:

– A small vial of white, freeze-dried powder (the peptide itself)

– A vial of bacteriostatic water (BAC water) as the diluent

– Syringes and needles for reconstitution and injection

This is where the practical preparation work begins. The powder needs to be mixed with a precise amount of BAC water to create a solution. Then the dose needs to be calculated and drawn accurately. If you’re new to this process, the next article in this series covers it step by step: <a href=”/peptide-injections-reconstitution-guide/”>Peptide Injections: What Happens After You Get a Prescription (Reconstitution Guide)</a>.

What "reconstitution" means and why it matters

Lyophilization — freeze-drying — is how manufacturers preserve peptides for storage and shipping. The powder form is stable for longer and at higher temperatures than a liquid solution. The trade-off is that you have to mix it yourself, correctly, before it’s usable.

Reconstitution is the process of adding a precise volume of BAC water to the vial and creating a stable solution. The math matters here: how much water you add determines the concentration (how much peptide is in each milliliter), which then determines how many units to draw in your syringe for a given dose.

Getting that math wrong — even by small amounts — means your dose is wrong. This is why dosing calculators exist. If you’re working with a compounding pharmacy and reconstituting your own doses, verifying the numbers with a free peptide dosing calculator before you draw your syringe is a basic sanity check worth making a habit.

For the full explanation of how that math works, see: <a href=”/peptide-dosage-calculator-guide/”>Peptide Dosage Calculator: What It Does and How to Check Your Math</a>.

The realistic picture for 2026

The peptide landscape is moving fast, and not always in a clean direction. The GLP-1 shortage created a compounding gray area that has since been legally contested. The FDA’s position on compounded GLP-1s has shifted. Some clinics are rigorous; others are not. The research on non-GLP-1 peptides ranges from decades old to genuinely preliminary.

What this means practically:

– **For GLP-1 therapy (semaglutide, tirzepatide):** work with a licensed provider who is transparent about whether they’re prescribing brand or compounded, and what the regulatory situation is in your state.

– **For other injectable peptides (BPC-157, sermorelin, etc.):** understand that these are not FDA-approved drugs in most contexts. The clinical rationale may be well-established in some cases; in others, you’re in earlier-stage territory. Ask your prescriber to be specific.

– **For topical/oral peptides in skincare or supplements:** a different (generally more accessible) regulatory category — but the marketing claims vary widely in their evidence base.

This blog will cover the practical education side of each of these. We’re not here to recommend a specific therapy or dose — that’s a conversation for your clinician. We’re here to make sure the preparation, math, and technique side doesn’t trip you up once you’ve made that decision.

Continue reading

*MANNA Editorial Team. This content is general education only and does not constitute medical advice, a treatment recommendation, or a dosing plan. Consult a licensed clinician before starting any peptide therapy.*

This article is for educational purposes only and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Manna products are not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any new supplement, especially if you are pregnant, nursing, taking medication, or managing a medical condition.

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