Patient Education Guide
Some Things You Should Know About GLP-1 Medications
How a hormone discovered in lizard venom became the most important weight loss breakthrough in decades, explained in plain English.
From Gut Hormones to a Medical Revolution
The story of GLP-1 drugs starts over 100 years ago with a simple question: why does eating food cause more insulin release than injecting sugar directly into the blood? That question led scientists across decades to discover a tiny hormone in your gut, and a protein in lizard venom, that would change medicine forever.
The Gut-Pancreas Connection
Scientists in England discovered that something in the intestines could lower blood sugar. They called it a chemical messenger, but it would take decades to find it.
The Incretin Effect Proven
Three research teams independently showed that eating sugar causes MUCH more insulin release than injecting the same sugar into the blood. The gut was sending a signal to the pancreas, and they called this the 'incretin effect.'
GLP-1 Is Discovered
Scientists including Joel Habener, Svetlana Mojsov, and Jens Juul Holst identified GLP-1 (glucagon-like peptide-1), a hormone made by cells in your intestines after you eat. It powerfully stimulates insulin release, but it breaks down in less than 2 minutes in your blood.
The Gila Monster Breakthrough
Dr. John Eng discovered a protein called exendin-4 in Gila monster saliva that works like GLP-1 but lasts MUCH longer. The lizard uses it to regulate metabolism between rare meals. This discovery made GLP-1 drugs possible.
First GLP-1 Drug Approved
Exenatide (Byetta), a synthetic version of the Gila monster protein, became the first GLP-1 drug. It required two shots per day.
Once-Daily Injection
Liraglutide (Victoza) used a clever fatty acid attachment to last longer in the body: one shot per day instead of two.
Once-Weekly Injection
Semaglutide (Ozempic) used an even more advanced fatty acid chain to last a full week. One tiny injection every 7 days.
The First GLP-1 Pill
Oral semaglutide (Rybelsus) became the first GLP-1 you could take by mouth, a huge engineering challenge solved by a special absorption-enhancing molecule called SNAC.
The Dual Agonist Era
Tirzepatide (Mounjaro/Zepbound) combined GLP-1 with a second hormone (GIP), producing up to 22.5% weight loss, the most ever seen from a medication.
What's Happening Now
Oral Wegovy pill approved (Dec 2025). Foundayo (orforglipron), the first true small-molecule GLP-1 pill, FDA approved (Apr 2026) with no food or water restrictions. Triple-agonist retatrutide showing up to 28% weight loss in trials. Monthly injections in development.
How GLP-1 Medications Work in Your Body
GLP-1 medications work on receptors (think of them as locks that the drug is the key to) in several different parts of your body. This is why they do more than just help with weight — they can improve blood sugar, heart health, and more.
Current GLP-1 and Related Medications
Here's a guide to the medications available today and how they differ, including compounded options with customizable additives.
Semaglutide
OzempicThe most well-known GLP-1 drug. A once-weekly injection that has been shown to improve blood sugar and cause significant weight loss. Available in 0.25mg, 0.5mg, 1mg, and 2mg doses.
Semaglutide
WegovyThe same molecule as Ozempic but FDA-approved specifically for weight loss at the higher 2.4mg dose. Also proven to reduce heart attack and stroke risk by 20%.
Semaglutide
Wegovy Pill / RybelsusSemaglutide in pill form. The original Rybelsus (up to 14mg) was for diabetes. The new oral Wegovy (25mg and 50mg) was approved in December 2025 for weight loss.
Liraglutide
SaxendaAn older GLP-1 drug requiring daily injection. Still used but being replaced by once-weekly options. Produces about 5-8% weight loss.
Tirzepatide
MounjaroThe first dual-action drug targeting both GLP-1 AND GIP receptors. Produces the largest weight loss of any currently approved drug, up to 22.5% in clinical trials.
Tirzepatide
ZepboundSame molecule as Mounjaro, approved specifically for weight management. Also approved for obstructive sleep apnea.
Semaglutide Compounded
Compounded SemaglutideCompounded semaglutide sourced from accredited pharmacies (PCAB, URAC certified). Compounded formulations may include additional ingredients tailored to patient needs. Common additives include vitamin B12 (supports energy, metabolism, and nervous system health during calorie restriction), glycine (supports muscle preservation, sleep quality, and has anti-inflammatory properties), L-carnitine (aids fat metabolism and energy production), and vitamin B6 (supports protein metabolism and immune function). Every batch is third-party tested for potency, sterility, and purity. Delivered in multi-dose vials for dosing flexibility.
Tirzepatide Compounded
Compounded TirzepatideCompounded tirzepatide from accredited pharmacies, combining the dual GLP-1/GIP mechanism with optional additives tailored to patient needs. Common additives include vitamin B12 (supports energy and metabolism), glycine (supports muscle preservation and has anti-inflammatory benefits), L-carnitine (aids fat metabolism and energy production), and vitamin B6 (supports protein metabolism and immune function). Sourced from FDA-registered facilities with third-party batch testing for potency, sterility, and purity. Delivered in multi-dose vials for dosing flexibility.
Orforglipron
FoundayoThe first non-peptide (small molecule) oral GLP-1 approved for weight loss. Unlike oral semaglutide, it can be taken any time of day with no food or water restrictions, just like any other pill. In trials, patients on the highest dose lost an average of 12% body weight over 72 weeks. FDA approved April 2026.
Dulaglutide
TrulicityA once-weekly GLP-1 drug primarily used for diabetes. Less weight loss than semaglutide or tirzepatide.
Exenatide
Byetta/BydureonThe original GLP-1 drug, derived from Gila monster venom. Less commonly used today but historically important.
How Much Weight Loss Can You Expect?
Every person responds differently, but here's what the large clinical trials showed on average. These numbers represent the average weight loss after about 1–1.5 years of treatment.
Note: Individual results vary. These are averages from clinical trials. Your results may be higher or lower depending on diet, exercise, starting weight, and other factors.
For reference, bariatric surgery (gastric sleeve or bypass) typically produces 25–35% weight loss. The newest medications are approaching these numbers without surgery.
What's Coming Next
The next wave of GLP-1-related drugs is already in late-stage clinical trials. Here's what to watch for.
Retatrutide
Eli LillyWhat it is
The first "triple agonist": it activates GLP-1, GIP, AND glucagon receptors.
Why it matters
The glucagon receptor activation increases your body’s energy expenditure (calorie burning), especially fat burning in the liver. Phase 2 showed ~24% weight loss at 48 weeks with the curve still going down. Phase 3 showed up to ~29%.
Weight loss
Up to ~29% in Phase 3 trials
CagriSema
Novo NordiskWhat it is
A combination of semaglutide (the Wegovy drug) plus cagrilintide (a long-acting version of amylin, another hormone your pancreas makes).
Why it matters
Amylin adds extra appetite suppression through different brain pathways than GLP-1 alone.
Weight loss
About 22% in the REDEFINE 1 trial. However, it did NOT beat tirzepatide head-to-head in the REDEFINE 4 trial.
MariTide
AmgenWhat it is
A once-MONTHLY injection combining GLP-1 activation with GIP blocking (the opposite approach from tirzepatide).
Why it matters
Monthly dosing would be a major convenience improvement.
Weight loss
Up to ~20% in Phase 2 data at 52 weeks.
Amycretin
Novo NordiskWhat it is
A single molecule that activates both GLP-1 and amylin receptors. Available as both injection and pill.
Why it matters
Showed ~24% weight loss in early trials at just 36 weeks.
Weight loss
~24% at 36 weeks in early trials.
Bimagrumab + GLP-1
Eli LillyWhat it is
An antibody that blocks muscle-wasting signals (myostatin), combined with a GLP-1 drug.
Why it matters
Solves the "muscle loss" problem. In trials, 93% of weight lost was fat (vs ~70% with GLP-1 alone). Patients actually gained muscle while losing fat.
Weight loss
93% of weight lost was fat; patients gained muscle.
Beyond GLP-1: Why Newer Drugs Target Multiple Hormones
You've probably heard terms like ‘dual agonist’ and ‘triple agonist.’ Here's what those extra hormones do.
GIP (Glucose-dependent Insulinotropic Polypeptide)
GIP is the other major ‘incretin’ hormone, discovered even before GLP-1.
Like GLP-1, it helps your pancreas release insulin after meals.
In the brain, GIP activates different appetite-regulating neurons than GLP-1, which may be why combining them (as in tirzepatide/Mounjaro) produces more weight loss.
Interestingly, GIP may also reduce the nausea caused by GLP-1, helping people tolerate higher doses.
The ‘GIP paradox’: Both activating AND blocking GIP seem to help with weight loss when combined with GLP-1. Scientists are still debating exactly why.
Glucagon
Glucagon is the ‘opposite’ of insulin: it raises blood sugar by telling your liver to release stored sugar.
So why would you WANT glucagon activity in a weight loss drug? Because glucagon also increases energy expenditure (calorie burning), stimulates fat breakdown (especially liver fat), and promotes thermogenesis (heat production from burning calories).
In retatrutide (the triple agonist), the GLP-1 and GIP components counterbalance glucagon’s blood sugar-raising effect, while you get the metabolic benefits.
This is why retatrutide showed an 82% reduction in liver fat, far more than GLP-1 drugs alone.
Safety and Side Effects
Like all medications, GLP-1 drugs have side effects. The good news: most are mild, temporary, and manageable. Here's what to know.
Always tell your healthcare provider about all medications you take. GLP-1 drugs can affect how quickly other oral medications are absorbed.