Tirzepatide
Mounjaro · Zepbound · GIP/GLP-1 · LY3298176
−20.9% body weight at 72 weeks, 15 mg (SURMOUNT-1)
Overview
Tirzepatide is a single peptide that activates two incretin receptors at once: the glucose-dependent insulinotropic polypeptide (GIP) receptor and the GLP-1 receptor. This dual agonism appears to produce larger reductions in appetite and body weight than GLP-1 agonism alone, while a fatty-acid modification supports once-weekly dosing.
In SURMOUNT-1, adults with obesity (without diabetes) lost roughly 15%, 19.5%, and 20.9% of body weight at the 5, 10, and 15 mg doses over 72 weeks. In the head-to-head SURPASS-2 diabetes trial, tirzepatide produced greater weight and HbA1c reductions than 1 mg semaglutide.
As with other incretins, tolerability is managed with a slow monthly titration. All figures here are summarized from published trials and labels for research reference only.
Key parameters
- Dose range
- 2.5–15 mg weekly
- Frequency
- Once weekly
- Half-life
- ~5 days (≈117 h)
- Route
- Subcutaneous
- Vial sizes
- 10 mg · 15 mg · 30 mg · 60 mg
- Regulatory status
- FDA-approved as Mounjaro (2022, type 2 diabetes) and Zepbound (2023, chronic weight management). Research-vial material is labeled for laboratory use only.
Mechanism of action
GLP-1 receptor agonism
Drives satiety, glucose-dependent insulin release, and slowed gastric emptying, as with single-agonist GLP-1 drugs.
GIP receptor agonism
Adds a second incretin signal thought to enhance insulin sensitivity and lipid handling and may blunt nausea relative to GLP-1 alone.
Glucose-dependent insulin secretion
Combined incretin signaling amplifies insulin release when glucose is elevated.
Dosing protocol & phases
| Phase | Weeks | Dose | Notes |
|---|---|---|---|
| Initiation | Weeks 1–4 | 2.5 mg once weekly | Starting dose for tolerability, not intended as a therapeutic dose. |
| Titration step 1 | Weeks 5–8 | 5 mg once weekly | — |
| Titration (as needed) | Every 4 weeks | Increase by 2.5 mg toward target | Available maintenance doses: 5, 10, and 15 mg. |
| Maintenance | Ongoing | 5, 10, or 15 mg once weekly | Hold at the lowest dose that maintains the response. |
Reconstitution guide
For educational and research reference only. Not intended for human consumption, not medical advice. Compounds discussed are sold and used for laboratory research purposes only.
30 mg vial + 2 mL bacteriostatic water
Concentration15,000 mcg/mL · 15 mg/mL
| Target dose | Draw volume | U-100 units |
|---|---|---|
| 2,500 mcg | 0.167 mL | 16.7 |
| 5,000 mcg | 0.333 mL | 33.3 |
| 7,500 mcg | 0.5 mL | 50 |
| 10,000 mcg | 0.667 mL | 66.7 |
Keeps mid-range maintenance draws comfortably inside a 50-unit syringe.
60 mg vial + 3 mL bacteriostatic water
Concentration20,000 mcg/mL · 20 mg/mL
| Target dose | Draw volume | U-100 units |
|---|---|---|
| 5,000 mcg | 0.25 mL | 25 |
| 10,000 mcg | 0.5 mL | 50 |
| 15,000 mcg | 0.75 mL | 75 |
Higher-strength mix suited to 10–15 mg maintenance.
Reconstitution calculator
Pre-filled with Tirzepatide's vial sizes. Adjust the water volume and target dose to see the exact draw, with warnings for doses that are hard to measure or won't fit a syringe.
At 5,000 micrograms per millilitre, a 2,500 microgram dose is 0.5 millilitres, or 50 units on a U-100 syringe, giving 4 doses per vial.
Supplies needed
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Recommended supply
Tirzepatide — research vial
From our verified partner Dynotides, with a third-party certificate of analysis per batch.
Injection supplies
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Bacteriostatic water
Diluent for reconstituting lyophilized vials.
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Insulin syringes (U-100)
0.3–0.5 mL, 29–31 G for accurate small draws.
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Alcohol prep pads
Sterile swabs for the vial stopper and site.
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Sharps container
Safe disposal of used needles.
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Storage fridge
Keeps reconstituted vials at 2–8 °C.
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Insulated travel case
Cooled, TSA-friendly case for travel.
Missed-dose guidance
Per the label: a missed weekly dose can be taken within 4 days (96 hours) of the scheduled time; if more than 4 days have passed, skip it and resume the regular weekly schedule. Do not double up.
Side effects & safety
| Category | Effect | Trial incidence |
|---|---|---|
| Gastrointestinal | NauseaSURMOUNT-1, pooled across doses; mostly mild–moderate during titration. | 28% |
| Gastrointestinal | Diarrhea | 23% |
| Gastrointestinal | Constipation | 17% |
| Gastrointestinal | Vomiting | 13% |
| General | Decreased appetite | — |
| Injection site | Local reactions | — |
Clinical trials & evidence
SURMOUNT-1
Phase 372 weeks · 2,539 adults with obesity, without diabetes
−15.0% / −19.5% / −20.9% at 5 / 10 / 15 mg vs −3.1% placebo.
NCT04184622 ↗SURPASS-2
Phase 340 weeks · 1,879 adults with type 2 diabetes
Greater HbA1c and weight reduction than semaglutide 1 mg.
NCT03987919 ↗SURMOUNT-2
Phase 372 weeks · Adults with obesity and type 2 diabetes
Significant weight reduction in a diabetic population.
NCT04657003 ↗
Storage & handling
- Lyophilized
- Store lyophilized powder refrigerated at 2–8 °C, protected from light.
- Reconstituted
- Refrigerate reconstituted solution at 2–8 °C and use within ~28–56 days. Do not freeze.
Comparisons
| Vs. | Target | Half-life | Dosing | Efficacy | Status |
|---|---|---|---|---|---|
| Semaglutide | GIP + GLP-1 vs GLP-1 | ~5 d vs ~7 d | 2.5–15 mg weekly vs 0.25–2.4 mg weekly | Greater weight/HbA1c reduction head-to-head (SURPASS-2) | Both approved |
| Retatrutide | GIP + GLP-1 vs GIP + GLP-1 + glucagon | ~5 d vs ~6 d | Weekly (both) | −20.9% vs −24.2% (different trials) | Approved vs investigational |
Featured in these stacks
Cagrilintide + Tirzepatide
This combination layers three appetite mechanisms by pairing the long-acting amylin analog cagrilintide with the dual-incretin agonist tirzepatide (GIP + GLP-1). The logic directly mirrors CagriSema — which combines amylin with GLP-1 — but substitutes tirzepatide, whose added GIP activity already produces some of the largest weight-loss figures of any approved single molecule (up to roughly 21% in SURMOUNT-1). Stacking amylin-mediated satiety on top is intended to push appetite suppression further still.
Sources & references
Frequently asked questions
How is tirzepatide different from semaglutide?
Tirzepatide activates both the GIP and GLP-1 receptors, whereas semaglutide targets only GLP-1. In the SURPASS-2 head-to-head trial, tirzepatide produced larger reductions in weight and HbA1c.
What are the maintenance doses?
The approved maintenance doses are 5, 10, and 15 mg once weekly, reached by stepping up 2.5 mg roughly every four weeks as tolerated.
Related protocols
Semaglutide
Ozempic
−14.9% mean body weight at 68 weeks (STEP 1)
Retatrutide
LY3437943
−24.2% body weight at 48 weeks, 12 mg (Phase 2, NEJM 2023)
Cagrilintide
AM833
−10.8% body weight at 26 weeks (monotherapy, Lancet 2021)
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For educational and research reference only. Not intended for human consumption, not medical advice. Compounds discussed are sold and used for laboratory research purposes only.