Tirzepatide Calculator
Built for compounded tirzepatide (Mounjaro/Zepbound). Select your vial, water volume, and titration dose to get exact syringe units. Full 6-step dosing chart included.
Vial size
BAC water added
Your concentration
5.00 mg/ml
Select your weekly dose
Select your weekly dose above to see how many units to draw.
Tirzepatide dosing chart
Pre-calculated syringe units for every titration dose at common vial/water setups. Higher doses require higher-concentration setups to stay within syringe capacity.
| Dose | Phase | 10mg + 1ml10 mg/ml | 10mg + 2ml5 mg/ml | 30mg + 2ml15 mg/ml | 30mg + 3ml10 mg/ml |
|---|---|---|---|---|---|
| 2.5 mg | Starting dose | 25 u | 50 u | 16.7 u | 25 u |
| 5 mg | Step 2 | 50 u | 100 u | 33.3 u | 50 u |
| 7.5 mg | Step 3 | 75 u | — | 50 u | 75 u |
| 10 mg | Step 4 | 100 u | — | 66.7 u | 100 u |
| 12.5 mg | Step 5 | — | — | 83.3 u | — |
| 15 mg | Maintenance | — | — | 100 u | — |
All values in syringe units (U-100). A dash means the dose exceeds syringe capacity at that concentration. Higher-dose phases need more concentrated solutions.
Worked reconstitution examples
Reconstitution math across the titration ladder, including how the compounded vial workflow compares to the Mounjaro or Zepbound pen.
10 mg compounded vial, 2.5 mg starting dose
Reconstitute with 2 mL of bacteriostatic water for 5 mg/mL concentration. A 2.5 mg weekly dose draws 0.5 mL, which is 50 units on a standard U-100 insulin syringe. The 10 mg vial yields four weekly starting doses, comfortably within the 28 day puncture window. Most compounded tirzepatide programs use this exact setup for the first month before stepping up.
10 mg compounded vial, 5 mg dose at week 5
Same vial reconstituted with 2 mL of water gives 5 mg/mL. The 5 mg dose now draws 1 mL, which fills a 1 mL syringe completely. Two weekly doses per vial, so one 10 mg vial covers half of the 4 week step. If your pharmacy ships 5 mg vials at this stage, reconstitute with 1 mL for the same 5 mg/mL concentration and a 100 unit draw.
20 mg compounded vial, 10 mg dose at week 13
Reconstitute the 20 mg vial with 2 mL for 10 mg/mL. A 10 mg dose is 1 mL or 100 units. Two doses per vial, used over two weeks. A higher-volume reconstitution (e.g., 4 mL for 5 mg/mL) is technically possible but the draw becomes 2 mL, which exceeds a single syringe. Stick with 2 mL of water per 20 mg vial at this dose level.
Mounjaro pen 7.5 mg single-use auto-injector
Pre-filled, no reconstitution required. The pen delivers a fixed 7.5 mg dose subcutaneously when the activation button is pressed against the skin. Use this calculator only for the compounded vial route; for branded Mounjaro or Zepbound pens, the dose is fixed by the device and no math is needed. The titration ladder is the same across both delivery formats.
Common compounded-tirzepatide mistakes
The four patterns most likely to cost a vial, a dose, or an entire titration step.
Over-diluting because the syringe fits more
Reconstituting a 10 mg vial with 4 mL or 5 mL gives a lower concentration that requires drawing 2 to 2.5 mL per 5 mg dose. That exceeds a single 1 mL syringe barrel and means splitting the dose across two injections. Use 2 mL of bacteriostatic water for 10 mg vials and 2 mL for 20 mg vials as the default; the draw stays inside one syringe at every titration step.
Confusing the compounded mg with the branded pen mg
Mounjaro 5 mg pen and a compounded 5 mg vial dose are pharmacologically identical (same molecule, same dose), but the compounded form requires reconstitution and a manual draw. Some users assume the 5 mg vial contains 5 mg per mL when it actually contains 5 mg total. Always read the vial label carefully and convert via concentration before drawing.
Skipping the 4 week hold to chase faster weight loss
Tirzepatide's titration is calibrated to gastric emptying adaptation, not to weight loss rate. Jumping from 2.5 mg to 7.5 mg after two weeks does not double the loss; it typically triggers severe nausea, vomiting, and a forced 1 to 2 week pause that loses momentum overall. Hold the full 4 weeks at each step even when side effects feel mild.
Discarding the vial before the 28 day window closes
Reconstituted tirzepatide is stable for at least 28 days refrigerated at 2 to 8 degrees C. Some users discard at two weeks out of caution and waste roughly half the vial. The benzyl alcohol preservative in BAC water keeps the solution safe across the full 28 day window provided sterile technique is used at every draw.
Standard titration schedule
Tirzepatide uses a 6-step escalation with 2.5 mg increases every 4 weeks. This is the schedule used in Klarovel protocols, matching the FDA-approved Mounjaro/Zepbound titration.
Starting dose. GI side effects typically appear in the first 1-2 weeks and then ease.
First noticeable appetite suppression. Some patients see early weight changes.
Dual GIP/GLP-1 effect is fully engaged. Cravings reduce significantly.
Strong therapeutic dose. Many patients maintain here long-term.
Near-maximum. Only increase if 10 mg was well tolerated with room for more effect.
Maximum dose. Not all patients need to reach this level. Stay where efficacy and side effects balance.
10 mg is often enough. Clinical data shows strong efficacy at 10 mg for most patients. Escalating to 12.5 or 15 mg adds incremental benefit but also increases side effect risk. Find your balance.
How tirzepatide works
Tirzepatide is a dual GIP/GLP-1 receptor agonist. Unlike semaglutide (GLP-1 only), it activates both the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors simultaneously.
This dual mechanism produces stronger appetite suppression and greater weight loss than single-target GLP-1 agonists. Clinical trials show 20-26% average body weight loss, compared to 15-17% with semaglutide. The trade-off is larger dose jumps (2.5 mg per step vs. fractional mg increases) and a longer total titration period (24+ weeks to reach maximum dose).
vs. Semaglutide
- Higher average weight loss (20-26% vs 15-17%)
- Dual receptor mechanism (GIP + GLP-1)
- Larger dose range (2.5-15 mg vs 0.25-2.4 mg)
- 6 titration steps vs 5
vs. Retatrutide
- FDA-approved (retatrutide is experimental)
- Dual agonist vs triple agonist (GIP + GLP-1 + glucagon)
- More clinical safety data available
- Steadier dose escalation (2.5 mg steps vs doubling)
Reconstituting tirzepatide
Same process as any peptide reconstitution. Clean workspace, room-temperature vials, inject BAC water against the glass wall, swirl gently. The key consideration for tirzepatide is concentration: higher doses (10-15 mg) need a more concentrated solution to keep the draw volume within syringe capacity.
Storage: Refrigerate at 2-8 degrees C. Stable for approximately 28 days with BAC water. Do not freeze. Label with date, concentration, and discard date.
Compounded vs. brand-name: The tirzepatide molecule is identical. Brand-name Mounjaro and Zepbound use pre-filled pens. Compounded tirzepatide comes as lyophilized powder in vials. This calculator is for the vial-based compounded form.
Common questions
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