What tirzepatide is
Tirzepatide itself is an active ingredient, not a single product. Sold as Zepbound (weight loss, sleep apnea) and Mounjaro (type 2 diabetes). Compounded versions are not FDA-approved. See our compounded GLP-1 guide.
Dosing
Weekly injection. 2.5 mg to start, stepping up by 2.5 mg every 4+ weeks to as much as 15 mg. Your clinician sets the pace, and it is common to stay at a dose longer if side effects are hard to manage.
How well it works
Up to 20.9% average weight loss over 72 weeks with Zepbound 15 mg in SURMOUNT-1. These are averages from clinical trials; your results may be different.
Tirzepatide cost
Zepbound self-pay is $299 to $449 with on-time refills. For every price option, read How much does compounded tirzepatide cost per month?. For the steps, read How to get Zepbound online in 2026.
Common side effects
Stomach-related side effects are the most common, especially while the dose is going up. Percentages show people on the medication vs placebo in the label trials.
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| Side effect | Wegovy 2.4 mg | Zepbound 5–15 mg | Foundayo |
|---|---|---|---|
| Nausea | 44% vs 16% | 25–29% vs 8% | 26–35% vs 10% |
| Diarrhea | 30% vs 16% | 19–23% vs 8% | 21–25% vs 11% |
| Vomiting | 24% vs 6% | 8–13% vs 2% | 13–24% vs 4% |
| Constipation | 24% vs 11% | 11–17% vs 5% | 20–27% vs 9% |
| Abdominal pain | 20% vs 10% | 9–10% vs 5% | 13–14% vs 7% |
| Fatigue | 11% vs 5% | 5–7% vs 3% | 6–9% vs 4% |
| Hair loss | 3% vs 1% | 4–5% vs 1% | 4–5% vs 2% |
Source: Wegovy (rev. 06/2026), Zepbound (rev. 08/2026) and Foundayo (rev. 07/2026) prescribing information.
Safety: GLP-1 medications carry a boxed warning for thyroid C-cell tumors and are not for people with a personal or family history of medullary thyroid carcinoma or MEN 2. Labels also warn about pancreatitis, gallbladder problems, low blood sugar with some diabetes drugs, kidney problems from dehydration and severe stomach problems. Talk to a licensed clinician about your history.
Legal status: Prescription only; sold as FDA-approved brand-name drugs; compounded versions are not FDA-approved.