GLP-1 Library

GLP-1 weight-loss medications, explained

A straight, physician-written guide to the drugs everyone is talking about — semaglutide, tirzepatide, the compounded-versus-brand question, oral options, and what's still in the pipeline.

JV
John Venzor, DO · Board-certified Internal Medicine
Medically reviewed · Last updated Jun 2026
The basics

What these medications actually do

GLP-1 medications started as diabetes drugs and turned into the most effective weight-loss treatment most people have ever had access to. The class is named for the gut hormone it copies, glucagon-like peptide-1. You almost certainly know the brand names: Ozempic and Wegovy (both semaglutide), Mounjaro and Zepbound (both tirzepatide).

They work by mimicking hormones your gut releases after a meal. That slows how fast your stomach empties, steadies blood sugar, and quiets the appetite signals in the brain that drive hunger and food noise. The result shows up on the scale. In the large semaglutide trials, people lost about 15% of their body weight on average; with tirzepatide, the highest dose pushed average loss past 20%. Those are numbers older weight-loss drugs never came close to.

The catch is that the details matter, and the market moved faster than most people could follow. There's compounded versus brand-name, injectable versus a new wave of pills, and a pipeline of next-generation drugs like retatrutide that may go further still. This library walks through all of it in plain language, so you can tell the marketing from the medicine before you decide anything.

The GLP-1 Library

Eight reads. Start anywhere.

A full walk-through of GLP-1 weight-loss medication, from how the drugs work to what's coming next. Each piece stands on its own. Read them in order, or jump to the one question you came here with.

01
How GLP-1s work
What the drugs are and how they drive weight loss.
02
Semaglutide
Ozempic, Wegovy, Rybelsus, and the results to expect.
03
Tirzepatide
Mounjaro, Zepbound, and why the dual action matters.
04
Semaglutide vs. tirzepatide
A head-to-head on results, dosing, and side effects.
05
Compounded vs. brand
The real difference, and where availability stands now.
06
Oral GLP-1s
Pills vs. injections, and how the efficacy compares.
07
Side effects
What's common, what's serious, and how to manage them.
08
What's coming next
Retatrutide, orforglipron, and the next generation.
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Common questions

Quick answers, before you dig in

The questions people ask first when they start looking into GLP-1 medications.

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They're a class of drugs that copy a natural gut hormone, glucagon-like peptide-1. That hormone tells your body you've eaten: it slows digestion, helps control blood sugar, and turns down appetite. Semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) are the two used most for weight loss.
Our how-it-works guide breaks down the biology in plain terms.
More than with any earlier weight-loss medication. In the main trials, semaglutide produced about 15% average body-weight loss over roughly 16 months, and tirzepatide's top dose pushed past 20%. Results vary a lot person to person, and they depend on staying on the medication and pairing it with diet and activity.
Yes — both, and we're upfront about the trade-offs. Compounded semaglutide and tirzepatide are the lower-cost path; brand-name Wegovy and Zepbound are the FDA-approved versions with monitoring. A clinician helps you weigh cost, access, and what fits your situation.
The compounded-vs-brand guide lays out the real differences.
For most adults who qualify, they have a well-studied safety record built over years of use in diabetes and weight management. The common side effects are digestive — nausea, especially early on. There are real reasons some people shouldn't take them, which is why a clinician reviews your history first.
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