What is Tirzepatide?
Tirzepatide is the first dual-action incretin drug: it activates both the GLP-1 receptor and the GIP receptor. Eli Lilly sells it as Mounjaro (type 2 diabetes, approved 2022) and Zepbound (weight management, approved 2023; obstructive sleep apnea added 2024).
That second mechanism matters. Head-to-head and cross-trial data consistently show tirzepatide producing greater average weight loss than semaglutide — it currently posts the strongest results of any FDA-approved weight loss medication.
Like all GLP-1 class drugs, it is prescription-only and works alongside diet and activity changes, not instead of them.
How it works
GLP-1 and GIP are both incretin hormones your gut releases after meals. Tirzepatide mimics both at once: the GLP-1 side suppresses appetite, slows stomach emptying, and boosts insulin; the GIP side appears to improve how your body handles fat and may reduce the nausea that GLP-1 alone can cause.
One weekly injection covers both pathways. In practice, patients report the same appetite quieting as semaglutide, often with stronger overall weight loss at the higher doses.
Dosing schedule
Tirzepatide titrates in 2.5 mg steps, moving up no faster than every 4 weeks. Not everyone needs the top dose — many maintain at 10 or 12.5 mg:
| Dose | When |
|---|---|
| 2.5 mg / week | Weeks 1–4 — starter dose, not therapeutic |
| 5 mg / week | Weeks 5–8 — first maintenance option |
| 7.5 mg / week | Step up if needed |
| 10 mg / week | Common maintenance dose |
| 12.5 mg / week | Step up if needed |
| 15 mg / week | Maximum dose |
Results in clinical trials
In SURMOUNT-1 (Jastreboff et al., NEJM 2022), the 15 mg dose produced 22.5% average weight loss over 72 weeks; even the 5 mg dose delivered 16%. Over half of participants on the top dose lost 20% or more of their body weight — results approaching bariatric surgery territory.
Side effects
Common
- Nausea
- Diarrhea
- Decreased appetite
- Vomiting
- Constipation
- Indigestion
- Injection site reactions
Serious (rare)
- Pancreatitis
- Gallbladder disease
- Kidney injury from dehydration
- Hypoglycemia (with insulin or sulfonylureas)
How much does Tirzepatide cost?
Tirzepatide pricing mirrors semaglutide: expensive branded list prices, meaningful cash-pay programs, and a shrinking compounded market.
| Route | Typical cost |
|---|---|
| Zepbound (list price) | ~$1,060 / month |
| Zepbound vials (LillyDirect cash-pay) | $349–$499 / month |
| Mounjaro (list price) | ~$1,070 / month |
| Compounded tirzepatide (when legal) | $200–$500 / month |
| With insurance coverage | $25–$100 / month copay (plan-dependent) |
Prices vary by clinic, dose, and location — always confirm directly. See real local pricing on our clinic listings.
Frequently asked questions
Is tirzepatide better than semaglutide?
For average weight loss, yes — trial data shows roughly 20–22% for tirzepatide versus about 15% for semaglutide, and the head-to-head SURMOUNT-5 trial confirmed the gap. Individual response varies though, and semaglutide has longer real-world history plus a cardiovascular outcomes approval. Cost and insurance coverage often end up deciding.
What is the difference between Mounjaro and Zepbound?
Same drug, different FDA approvals. Mounjaro is labeled for type 2 diabetes; Zepbound is labeled for chronic weight management and obstructive sleep apnea. Doses are identical (2.5–15 mg weekly). Which one you are prescribed mostly determines what insurance will cover.
How much weight can I lose on tirzepatide?
Trial averages: 16% of body weight at 5 mg, 21.4% at 10 mg, and 22.5% at 15 mg over 72 weeks (SURMOUNT-1). For a 250 lb person, that is roughly 40–56 lbs. Real-world results vary with dose, adherence, and lifestyle changes.
Do I need a prescription for tirzepatide?
Yes, always. Tirzepatide is prescription-only. Unregulated vials sold online without a prescription are illegal and carry real risks — wrong doses, contamination, no sterility testing. Get evaluated by a licensed provider, in person or via telehealth.
Related medications
This page is for educational purposes only and is not medical advice. Tirzepatide is a prescription medication — talk to a licensed healthcare provider about whether it is right for you. GLPFinders is a directory service and does not prescribe, sell, or dispense medications.