Calculate compounded tirzepatide (Mounjaro/Zepbound) reconstitution and weekly injection dose. The most effective GLP-1 for weight loss — up to 22.5% body weight reduction.
Tirzepatide follows a 5-step titration schedule. Each dose level is maintained for at least 4 weeks before increasing. Slower titration reduces side effects.
| Step | Weeks | Weekly Dose | Units (5mg/1mL, 100u) | Avg Weight Loss |
|---|---|---|---|---|
| Step 1 | 1-4 | 2,500 mcg (2.5mg) | 50 units | Starting dose |
| Step 2 | 5-8 | 5,000 mcg (5mg) | 100 units (full vial) | ~5% body weight |
| Step 3 | 9-12 | 7,500 mcg (7.5mg) | Use 10mg vial | ~10% body weight |
| Step 4 | 13-16 | 10,000 mcg (10mg) | Use 10mg vial | ~15% body weight |
| Step 5 | 17+ | 15,000 mcg (15mg) | Use 15mg vial | Up to 22.5% |
| Weekly Dose | Units (100u syringe) | mL to Draw | Weeks/Vial |
|---|---|---|---|
| 2,500 mcg (2.5mg) | 50 units | 0.50 mL | 2 weeks |
| 5,000 mcg (5mg) | 100 units | 1.00 mL | 1 week |
| Weekly Dose | Units (100u syringe) | mL to Draw | Weeks/Vial |
|---|---|---|---|
| 2,500 mcg | 50 units | 0.50 mL | 4 weeks |
| 5,000 mcg | 100 units | 1.00 mL | 2 weeks |
| 7,500 mcg | 75 units (use 1mL water) | 0.75 mL | ~1.3 weeks |
| 10,000 mcg | 100 units (use 1mL water) | 1.00 mL | 1 week |
Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. It was first approved as Mounjaro for type 2 diabetes and later as Zepbound for chronic weight management.
Inject subcutaneously once weekly on the same day each week. Recommended sites: abdomen, front of thighs, or upper arms. Rotate injection sites. Can be taken at any time, with or without meals.
Tirzepatide and semaglutide are both injectable GLP-1 receptor agonists used for weight management, but they differ in mechanism, efficacy, and side effect profile. Understanding these differences helps inform treatment decisions.
| Factor | Tirzepatide (Mounjaro/Zepbound) | Semaglutide (Ozempic/Wegovy) |
|---|---|---|
| Mechanism | Dual agonist — activates both GIP and GLP-1 receptors | Single agonist — GLP-1 receptor only |
| Average weight loss | 20-26% of body weight (SURMOUNT trials) | 12-17% of body weight (STEP trials) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Titration steps | 6 steps (2.5→5→7.5→10→12.5→15 mg) | 5 steps (0.25→0.5→1→1.7→2.4 mg) |
| Time to maintenance | 20+ weeks | 16+ weeks |
| Nausea rate | ~29% (SURMOUNT-1) | ~44% (STEP 1) |
| A1C reduction | Up to 2.3% | Up to 1.8% |
| FDA approval (obesity) | 2023 (Zepbound) | 2021 (Wegovy) |
| Compounded availability | Available (lyophilized powder) | Available (lyophilized powder) |
| Cost (compounded, monthly) | $200-500 | $150-400 |
The dual GIP+GLP-1 mechanism of tirzepatide appears to provide additional metabolic benefits beyond appetite suppression alone. GIP receptor activation enhances insulin secretion, improves fat metabolism, and may contribute to the greater weight loss observed in clinical trials. For detailed semaglutide dosing with week-by-week titration schedules, see our semaglutide dosage calculator.
Tirzepatide uses a 6-step titration protocol with dose increases every 4 weeks. Each step allows the body to adapt before moving to a higher dose, reducing the severity of gastrointestinal side effects.
| Step | Weeks | Weekly Dose | Purpose | Expected Effects |
|---|---|---|---|---|
| 1 (Starting) | 1-4 | 2.5 mg | Initial adjustment — not a therapeutic dose for weight loss | Mild appetite reduction, possible light nausea |
| 2 | 5-8 | 5 mg | First therapeutic dose. Appetite suppression becomes noticeable | Reduced hunger, early weight loss begins (1-3 lbs/week) |
| 3 | 9-12 | 7.5 mg | Intermediate dose. Many users see significant results here | Steady weight loss, improved blood sugar levels |
| 4 | 13-16 | 10 mg | Standard maintenance dose for most users | Substantial weight loss, GI side effects typically resolved |
| 5 | 17-20 | 12.5 mg | Enhanced dose if weight loss plateau at 10 mg | Continued weight loss, possible brief return of nausea |
| 6 (Maximum) | 21+ | 15 mg | Maximum approved dose | Peak weight loss effect (average 22-26% body weight) |
Use our calculator at the top of this page to determine exact syringe units for any tirzepatide dose based on your vial concentration and water volume.
Tirzepatide's efficacy is supported by the SURMOUNT clinical trial program, one of the largest obesity treatment trial series ever conducted.
| Trial | Participants | Duration | Key Results |
|---|---|---|---|
| SURMOUNT-1 | 2,539 adults with obesity (no diabetes) | 72 weeks | Average weight loss: 15 mg dose = 22.5% body weight. 5 mg = 15%, 10 mg = 19.5%. 96% of participants on 15 mg lost ≥5% body weight. |
| SURMOUNT-2 | 938 adults with obesity + type 2 diabetes | 72 weeks | Average weight loss: 15 mg = 14.7%, 10 mg = 12.8%. A1C reduction: 2.1-2.3%. Superior to semaglutide 1 mg comparator. |
| SURMOUNT-3 | 579 adults (intensive lifestyle + tirzepatide) | 72 weeks | Combined with intensive behavioral therapy: average 26.6% weight loss at 15 mg dose. The highest weight loss observed in any GLP-1 trial to date. |
| SURMOUNT-4 | 670 adults (weight regain prevention) | 88 weeks | After initial weight loss, continuing tirzepatide maintained weight loss vs. 14% regain in placebo group. Demonstrates need for ongoing treatment. |
The most common adverse events were gastrointestinal: nausea (29%), diarrhea (23%), and constipation (11%). Most GI side effects were mild to moderate and decreased over time. Discontinuation due to adverse events occurred in 4.3-7.1% of participants across dose groups. Serious adverse events were rare and comparable to placebo rates.
For general peptide dosing and reconstitution, see our peptide calculator or read the complete reconstitution guide. For the healing peptide BPC-157, visit our BPC-157 dosage calculator.