Branded tirzepatide (Mounjaro, Zepbound) ships in pre-filled pens with doses already measured — no math needed. Compounded tirzepatide (where still legally available via 503A pharmacies for documented clinical need) ships as a lyophilised powder in multi-dose vials, and users have to reconstitute and draw each dose themselves. This page covers the exact vial sizes, reconstitution volumes, and syringe-unit targets for the standard SURMOUNT titration schedule — plus a free calculator pre-filled with a typical compounded protocol.
Key Takeaways
- —Compounded tirzepatide typically ships in 30 mg, 40 mg, or 60 mg vials. 2 mL of BAC water is the most common reconstitution volume.
- —At 30 mg + 2 mL, the concentration is 15 mg/mL (15,000 mcg/mL). A 2.5 mg starting dose = 0.167 mL = 17 units on a U-100 insulin syringe.
- —FDA-approved titration: 2.5 mg weekly × 4 wk → 5 mg × 4 wk → 7.5 mg × 4 wk → 10 mg × 4 wk → 12.5 mg × 4 wk → 15 mg. Never skip a 4-week step.
- —A single 30 mg vial gives you 12 doses at 2.5 mg, 6 doses at 5 mg, 4 doses at 7.5 mg, or 3 doses at 10 mg.
- —Compounded tirzepatide access is restricted following the FDA shortage-list removal (tirzepatide vs semaglutide guide).
| Vial Size | BAC Water | Concentration | Typical Use |
|---|---|---|---|
| 10 mg | 1 mL | 10 mg/mL | Small starter vials (rare) |
| 30 mg | 2 mL | 15 mg/mL | Most common for titration weeks 1–16 |
| 40 mg | 2 mL | 20 mg/mL | Higher-concentration option |
| 60 mg | 3 mL | 20 mg/mL | High-volume protocols; reduces refill frequency |
The 30 mg / 2 mL reconstitution is the practical default: concentration is high enough that even a 2.5 mg dose stays above the 0.1 mL small-volume threshold where insulin-syringe measurement becomes imprecise.
Using the standard 30 mg vial + 2 mL BAC water = 15,000 mcg/mL concentration:
| Titration Week | Weekly Dose | Draw Volume | U-100 Units |
|---|---|---|---|
| 1–4 | 2.5 mg | 0.167 mL | 17 units |
| 5–8 | 5 mg | 0.333 mL | 33 units |
| 9–12 | 7.5 mg | 0.500 mL | 50 units |
| 13–16 | 10 mg | 0.667 mL | 67 units |
| 17–20 | 12.5 mg | 0.833 mL | 83 units |
| 21+ | 15 mg | 1.000 mL | 100 units (full syringe) |
At doses above ~50 units, an insulin syringe (typical capacity 100 units / 1 mL) is still usable but many practitioners switch to a 1 mL tuberculin syringe for the 12.5 mg and 15 mg doses to reduce the risk of an incomplete draw.
Reaching maintenance dose via the full 20-week titration schedule takes the following vial counts:
| Target Maintenance | Total mg Through Week 20 | 30 mg Vials | 60 mg Vials |
|---|---|---|---|
| 5 mg maintenance | 30 mg titration + 10 mg × remaining = 30 + 520 = varies | ~18 | ~9 |
| 10 mg maintenance | 50 mg titration + 10 mg × remaining | ~35 | ~18 |
| 15 mg maintenance | 90 mg titration + 15 mg × remaining | ~50+ | ~25+ |
For year-one planning: a 10 mg maintenance patient uses ~520 mg of tirzepatide over 52 weeks (10 mg × 52), equivalent to 18 × 30 mg vials or 9 × 60 mg vials beyond the titration phase.
Cost math for compounded access at ~$229–349/month vs branded Zepbound at $1,060/month is covered in the tirzepatide vs semaglutide guide.
The Next Pep calculator opens pre-filled with tirzepatide's first titration step.
Other common presets:
Tirzepatide (like other peptides) stores 28 days at 2–8 °C after reconstitution. Do not freeze. Branded pen vials (Zepbound, Mounjaro) have specific manufacturer stability data — consult the prescribing information. Compounded tirzepatide follows standard peptide reconstitution stability rules.
For a compounded 30 mg vial reconstituted with 2 mL of BAC water (15 mg/mL concentration): the 2.5 mg FDA starting dose is approximately 17 units on a U-100 insulin syringe. This increases to 33 / 50 / 67 / 83 / 100 units as the titration progresses through 5 / 7.5 / 10 / 12.5 / 15 mg doses.
No. The titration schedule exists specifically to minimise gastrointestinal side effects (nausea, vomiting, diarrhea), which scale with dose. Skipping steps substantially increases dropout risk without providing any efficacy benefit. Follow the same 4-week-per-step schedule used in the SURPASS and SURMOUNT trials.
2 mL is the most common reconstitution volume, yielding 15 mg/mL. Some protocols use 1.5 mL for 20 mg/mL concentration to reduce injection volume at high doses. The calculator supports both.
Mostly restricted. The FDA declared the tirzepatide shortage over in late 2024, ending broad 503A compounding. Limited exceptions remain for documented clinical needs. For most cash-pay patients, Lilly's direct-from-manufacturer program offers tirzepatide at ~$499/month — the cheapest legal access currently. Details in the tirzepatide vs semaglutide guide.
At the standard 30 mg / 2 mL (15,000 mcg/mL) concentration: 10 mg = 0.667 mL = 67 units on a U-100 insulin syringe. The calculator shows this directly.
This article is for research and informational purposes only. Tirzepatide is an FDA-regulated prescription medication. Compounded tirzepatide access is restricted following the FDA's February 2026 shortage-list decision. Consult a licensed healthcare professional for any tirzepatide protocol.
Research Disclaimer. All content on Next Pep is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. Consult a licensed healthcare professional before considering any peptide protocol.
Peptide reconstitution errors are the most common dosing mistake. Free calculator covering insulin syringe units, BAC water volumes, and vial concentration math.
Most peptide comparison content is vendor marketing. A mechanism-first framework for comparing any two peptides on data that actually predicts outcomes — plus a free tool.