VentralinkGLP-1 Medications
How the new weight loss medications actually work
- GLP-1 medications work by slowing digestion, reducing appetite, and improving blood sugar— they address the biology that makes weight loss hard.
- Semaglutide (Wegovy/Ozempic) and tirzepatide (Zepbound/Mounjaro) are the main options — tirzepatide works on two receptors and produces greater weight loss.
- Doses start low and increase gradually over 4-16 weeks to minimize side effects.
- Weight loss typically begins in the first month and continues for 12-18 months before plateauing.
- These medications don't replace lifestyle changes — they make them more sustainable by reducing hunger and cravings.
If you've been following the news, you've heard of Ozempic, Wegovy, Mounjaro, and Zepbound. These medications have transformed obesity treatment — but how do they actually work?
This article explains the science in plain English: what these drugs do in your body, how they differ from each other, and what to expect if you take them.
What Are GLP-1 Medications?
GLP-1 stands for "glucagon-like peptide-1" — a hormone your body naturally produces after eating. This hormone tells your brain you're full, slows down digestion, and helps regulate blood sugar.
GLP-1 medications are synthetic versions of this hormone, designed to last much longer than the natural version (which breaks down in minutes). By mimicking and amplifying what your body already does, they help reduce appetite and improve metabolic health.
These drugs were originally developed for type 2 diabetes — that's why you might hear about Ozempic (for diabetes) and Wegovy (for weight loss). They're the same medication (semaglutide) at different doses and with different FDA approvals.
How They Work: Three Mechanisms
GLP-1 medications affect your body in three main ways:
Slow Stomach Emptying
Food stays in your stomach longer, so you feel full for hours after eating — not just minutes.
Reduce Appetite
They act on appetite centers in the brain, reducing hunger and — importantly — reducing cravings and "food noise."
Improve Blood Sugar
They enhance insulin release when blood sugar is high, improving metabolic health beyond just weight.
The appetite effect is what patients notice most. Many describe it as "food noise" finally going quiet — the constant thoughts about food, the cravings, the urge to keep eating even when full. For people who have struggled with these feelings their whole lives, this can feel transformative.
The Main Medications
Here's a quick overview of the GLP-1 and related medications currently available:
| Medication | Type | How Taken | FDA Approved For |
|---|---|---|---|
Semaglutide Wegovy, Ozempic | GLP-1 | Weekly injection | Wegovy: obesity Ozempic: diabetes |
Semaglutide Rybelsus | GLP-1 | Daily pill | Diabetes (lower dose) |
Tirzepatide Zepbound, Mounjaro | Dual GLP-1/GIP | Weekly injection | Zepbound: obesity Mounjaro: diabetes |
Liraglutide Saxenda, Victoza | GLP-1 | Daily injection | Saxenda: obesity Victoza: diabetes |
Semaglutide and tirzepatide are the most effective options currently available. Liraglutide (Saxenda) was the previous generation — it still works, but produces less weight loss and requires daily rather than weekly injections.
💡 What Makes Tirzepatide Different?
Tirzepatide (Zepbound/Mounjaro) isn't just a GLP-1 — it's a "dual agonist" that also activates GIP receptors. GIP is another gut hormone involved in appetite and metabolism.
This dual action may explain why tirzepatide produces more weight loss than semaglutide in head-to-head trials (20% vs 14% average weight loss). Whether this translates to better long-term health outcomes is still being studied.
What to Expect: The Timeline
If you start a GLP-1 medication, here's a typical progression:
You start at a low dose to let your body adjust. Some appetite reduction, possibly some nausea. Weight loss begins for most people.
Dose increases every 4 weeks until you reach the target dose. Appetite suppression strengthens. GI side effects typically improve as your body adapts.
Most weight loss occurs during this period. You're at or near your maintenance dose. Eating patterns have typically changed significantly.
Weight loss slows and plateaus. This is normal — it doesn't mean the medication stopped working. It's now helping you maintain your new weight.
The gradual dose escalation is important. Starting at full dose would cause significant nausea and GI symptoms for most people. The slow ramp-up lets your body adapt.
Injectable vs. Oral: What's Available
Most GLP-1 medications are weekly injections using a simple pen device (similar to insulin pens). The needle is very small and the injection is subcutaneous — under the skin, not into muscle.
Oral options exist but have limitations:
Rybelsus (oral semaglutide) is currently approved for diabetes at doses up to 14mg daily. It must be taken on an empty stomach with minimal water, then you wait 30 minutes before eating or drinking anything else. The obesity-dose oral semaglutide is newer and may expand options.
New oral medications are in development. Orforglipron, a daily pill that doesn't have the food/water restrictions, is expected in 2026. This may make GLP-1 therapy more accessible for people who prefer pills over injections.
🎯 This Is Not a Magic Pill
GLP-1 medications are powerful tools, but they're not magic. They make weight loss easier by reducing hunger and cravings — but you still need to make different choices about food and activity.
Think of it this way: these medications quiet the biological forces working against you. They don't do the work for you, but they make the work possible in a way it wasn't before.
All the major trials combined medication with lifestyle counseling. The best results come from combining both.
The Bottom Line
GLP-1 medications represent a genuine breakthrough in obesity treatment. They work by mimicking natural hormones that control appetite and metabolism — slowing digestion, reducing hunger, and improving blood sugar control.
Semaglutide (Wegovy/Ozempic) and tirzepatide (Zepbound/Mounjaro) are the most effective options. They're taken as weekly injections, with doses gradually increased over several weeks to minimize side effects.
But understanding how they work is just the beginning. The next question is: how well do they actually work in real patients? That's what the clinical trials show — and the results are impressive.
📊 Next: The Evidence
In the next article, we'll look at what the major clinical trials actually found: how much weight people lost, how long they kept it off, and — most importantly — whether these medications reduce heart attacks, strokes, and death.