What are GLP-1 drugs?
GLP-1 receptor agonists are a class of medications that mimic gut hormones your body releases after eating — lowering blood sugar and reducing appetite. They were developed for type 2 diabetes, and their strong effect on weight led to a second wave of approvals for obesity. Most are once-weekly injections; a few are daily, and one (Rybelsus) is a pill.
What separates them is how many hormone receptors each one activates. The original drugs hit a single receptor (GLP-1). Newer ones add a second (GIP) or a third (glucagon) — and more receptors have generally meant more weight loss.
Every GLP-1 drug, side by side
Here's the comparison no one else puts in one place — effectiveness, dosing, price, and mechanism for each drug, in a single table. Each drug links to its full guide.
| Drug | Sold as | Receptors | Avg. weight loss | Dosing | List price | Status |
|---|---|---|---|---|---|---|
| Tirzepatide | Mounjaro · Zepbound | Dual (GIP/GLP-1) | ~21% | Weekly injection | ~$1,060–$1,070/mo | FDA approved |
| Retatrutide | – | Triple (GIP/GLP-1/glucagon) | ~24% | – | – | Investigational |
| Semaglutide | Ozempic · Wegovy · Rybelsus | Single (GLP-1) | ~15% | Weekly injection · Daily pill | ~$935–$1,349/mo | FDA approved |
| Liraglutide | Victoza · Saxenda | Single (GLP-1) | ~7% | Daily injection | – | FDA approved |
| Dulaglutide | Trulicity | Single (GLP-1) | – | Weekly injection | – | FDA approved |
Weight-loss figures are average total body-weight loss in each drug's pivotal trials, at the top dose, over different durations and populations, so they are directional, not head-to-head. ⚠ Draft figures pending verification.
How GLP-1 drugs work
All of them mimic GLP-1, a hormone that curbs appetite and prompts insulin release after meals. The difference is how many receptors they hit — the single clearest way to understand why some produce more weight loss than others.
Single-agonist — semaglutide, liraglutide, dulaglutide. Hits GLP-1 only.
Receptors it activates
Single agonist · GLP-1
- GLP-1
Curbs appetite and triggers insulin after meals
- GIP
Not activated
- glucagon
Not activated
Dual-agonist — tirzepatide (Mounjaro, Zepbound). Adds the GIP receptor.
Receptors it activates
Dual agonist · GLP-1 + GIP
- GLP-1
Curbs appetite and triggers insulin after meals
- GIP
Amplifies the insulin response and how the body handles fat
- glucagon
Not activated
Triple-agonist — retatrutide (investigational). Adds glucagon on top of GIP and GLP-1.
Receptors it activates
Triple agonist · GLP-1 + GIP + glucagon
- GLP-1
Curbs appetite and triggers insulin after meals
- GIP
Amplifies the insulin response and how the body handles fat
- glucagon
Lifts energy expenditure, so the body burns more
The GLP-1 drugs, one by one
Each profile links to a full guide with dosing, cost, side effects, and how to get it.
- 1. Tirzepatide
- Sold as
- Mounjaro, Zepbound
- Used to treat
- Type 2 diabetes · Weight management & sleep apnea
- Class
- GIP/GLP-1 receptor agonist
- Avg. weight loss
- ~21%
-
- Sold as
- —
- Used to treat
- —
- Class
- GIP/GLP-1/glucagon receptor agonist
- Avg. weight loss
- ~24%
- 3. Semaglutide
- Sold as
- Ozempic, Wegovy, Rybelsus
- Used to treat
- Type 2 diabetes · Weight management
- Class
- GLP-1 receptor agonist
- Avg. weight loss
- ~15%
- 4. Liraglutide
- Sold as
- Victoza, Saxenda
- Used to treat
- Type 2 diabetes · Weight loss
- Class
- GLP-1 receptor agonist
- Avg. weight loss
- ~7%
- 5. Dulaglutide
- Sold as
- Trulicity
- Used to treat
- Type 2 diabetes
- Class
- GLP-1 receptor agonist
- Avg. weight loss
- —
Side effects and safety across the class
The GLP-1 drugs share a side-effect profile: mostly digestive, mostly early, and mostly temporary. Nausea, diarrhea, constipation, and vomiting are the common ones, worst after a dose increase and easing as the body adjusts. Rare but serious risks include pancreatitis, gallbladder problems, kidney injury from dehydration, and serious allergic reactions.
Which GLP-1 is right for you?
The strongest option isn't automatically the right one. Tirzepatide leads on weight loss, but semaglutide has a longer record and the only pill; liraglutide is the cheapest (and the only one with a generic); and the best real-world choice usually comes down to what your insurance covers, how you tolerate it, and whether you want an injection or a tablet.
What GLP-1 drugs cost
Brand-name GLP-1s list around $1,000 a month or more before insurance, though what people actually pay ranges widely with coverage, savings cards, and self-pay vial programs. Generic liraglutide is the cheapest legitimate option; retatrutide has no price because it isn't approved. See each drug's guide for its full cost breakdown, and our blog roundups on the cheapest ways to get a GLP-1.