Tirzepatide Dosage & Reconstitution Guide
Titration schedule, reconstitution math, and syringe draw reference — everything in one place.
What Is Tirzepatide?
Tirzepatide is a dual GIP and GLP-1 receptor agonist developed by Eli Lilly and approved by the FDA under the brand names Mounjaro (for type 2 diabetes) and Zepbound (for weight management). It is the first approved dual incretin receptor agonist, distinguishing it from GLP-1 only agonists like semaglutide. Compounded and research-grade tirzepatide exists in a separate market and is not FDA-approved. This guide covers reconstitution and dosing math for lyophilized research-grade tirzepatide only.
Important note: This guide is for research purposes only and does not apply to FDA-approved tirzepatide products (Mounjaro, Zepbound). Those products are available by prescription only and come pre-formulated — they do not require reconstitution.
Tirzepatide vs Semaglutide
Key Differences
Tirzepatide targets two receptors (GIP and GLP-1) compared to semaglutide's single GLP-1 target. Phase 3 clinical trial data (SURMOUNT program) showed tirzepatide achieving up to 22.5% mean body weight reduction at the 15 mg dose over 72 weeks, compared to approximately 15% for semaglutide at its maximum studied dose. Both compounds require similar titration approaches to manage gastrointestinal side effects.
| Parameter | Tirzepatide | Semaglutide |
|---|---|---|
| Receptor targets | GIP + GLP-1 | GLP-1 only |
| Starting dose | 2.5 mg | 0.25 mg |
| Maximum studied dose | 15 mg | 2.4 mg |
| Injection frequency | Once weekly | Once weekly |
| Brand names | Mounjaro, Zepbound | Ozempic, Wegovy |
Titration Schedule
Standard Tirzepatide Titration Protocol
Tirzepatide requires gradual dose titration. The titration schedule mirrors the FDA-approved protocol used in clinical trials.
| Week | Dose | Frequency | Notes |
|---|---|---|---|
| Weeks 1–4 | 2.5 mg | Once weekly | Starting dose. GI side effects most common here. |
| Weeks 5–8 | 5.0 mg | Once weekly | Advance only if 2.5 mg well tolerated. |
| Weeks 9–12 | 7.5 mg | Once weekly | Mid-range dose. Common stopping point for many protocols. |
| Weeks 13–16 | 10.0 mg | Once weekly | Higher range — advance cautiously. |
| Weeks 17–20 | 12.5 mg | Once weekly | Near maximum dose. |
| Weeks 21+ | 15.0 mg | Once weekly | Maximum studied dose. |
Do not advance the dose if nausea is persistent or food intake is severely reduced. Holding at the current dose for an additional 4 weeks is preferable to discontinuing.
Reconstitution Reference
How Much BAC Water to Add
Tirzepatide is typically used at higher doses than semaglutide. A concentration of 5.0–10.0 mg/mL keeps injection volumes manageable at mid to high doses.
| Vial size | BAC water | Concentration | Doses at 2.5 mg | Doses at 5.0 mg |
|---|---|---|---|---|
| 5 mg | 1.0 mL | 5.0 mg/mL | 2 | 1 |
| 10 mg | 1.0 mL | 10.0 mg/mL | 4 | 2 |
| 10 mg | 2.0 mL | 5.0 mg/mL | 4 | 2 |
| 15 mg | 1.5 mL | 10.0 mg/mL | 6 | 3 |
| 20 mg | 2.0 mL | 10.0 mg/mL | 8 | 4 |
Calculate your exact syringe draw
Open the Calculator →Syringe Draw Reference
| Dose | Draw to |
|---|---|
| 2.5 mg | 50 units |
| 5.0 mg | 100 units |
| 7.5 mg | 150 units * |
| 10.0 mg | 200 units * |
| 12.5 mg | 250 units * |
| 15.0 mg | 300 units * |
| Dose | Draw to |
|---|---|
| 2.5 mg | 25 units |
| 5.0 mg | 50 units |
| 7.5 mg | 75 units |
| 10.0 mg | 100 units |
| 12.5 mg | 125 units * |
| 15.0 mg | 150 units * |
* Volumes above 100 units (1 mL) require multiple injections. At 10.0 mg/mL, doses up to 10 mg fit in a single 1 mL syringe. This concentration is recommended for doses of 5 mg and above.
Supplies Required
| Item | Spec | Notes |
|---|---|---|
| Tirzepatide vial | Lyophilized powder | Keep at -20°C until use |
| Bacteriostatic water | USP, 0.9% benzyl alcohol | 30 mL multi-dose vial |
| Insulin syringes | U-100, 31g, 0.3–1 mL | Low dead-space preferred |
| Alcohol prep pads | 70% isopropyl, sterile | One per vial entry, one per site |
| Sharps container | Puncture-resistant | Required |
Sourcing
Recommended Research Supplier
PSPeptides carries third-party tested, research-grade tirzepatide with published COAs.
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