Compounded GLP-1 dosage calculator
Compounded semaglutide and tirzepatide are prescribed in milligrams but drawn by volume from a vial, and the strength varies between pharmacies. Enter your dose and your vial's concentration to get the exact units to draw on a U-100 insulin syringe.
= 2.5 mg/ml concentration
Draw
10
units on a U-100 insulin syringe
0.1 ml at 2.5 mg/ml
Always confirm the concentration printed on your own vial — compounded strengths are not standardized, and a wrong concentration is the most common cause of GLP-1 overdose. This is an educational tool, not medical advice.
How the math works
On a U-100 insulin syringe, one unit is 0.01 ml. To find your units, divide the dose in mg by the concentration in mg/ml to get the volume, then multiply by 100. A 5 mg tirzepatide dose from a 20 mg/ml vial is 0.25 ml, or 25 units. The dose stays fixed while the volume changes with concentration, which is why reading the strength off your own vial is the step that matters most.7
Semaglutide titration schedule
Compounded semaglutide dosing generally follows the Wegovy label, stepping up every 4 weeks so the gut adjusts before each increase.1
| Weeks | Weekly dose | Note |
|---|---|---|
| 1–4 | 0.25 mg | Initiation |
| 5–8 | 0.5 mg | |
| 9–12 | 1 mg | |
| 13–16 | 1.7 mg | |
| 17+ | 2.4 mg | Maintenance (or 1.7 mg) |
Maximum labeled dose for weight management is 2.4 mg/week.1 The STEP 1 trial reported a mean 14.9% weight reduction at 2.4 mg over 68 weeks.5
Tirzepatide titration schedule
Compounded tirzepatide dosing generally follows the Zepbound label: start at 2.5 mg, move to 5 mg after 4 weeks, then increase in 2.5 mg steps no sooner than every 4 weeks up to a maximum of 15 mg.3
| Weeks | Weekly dose | Note |
|---|---|---|
| 1–4 | 2.5 mg | Initiation |
| 5–8 | 5 mg | |
| 9–12 | 7.5 mg | |
| 13–16 | 10 mg | |
| 17–20 | 12.5 mg | |
| 21+ | 15 mg | Maximum |
Common maintenance doses are 5, 10, and 15 mg/week.3 SURMOUNT-1 reported a mean 22.5% weight reduction at 15 mg over 72 weeks.6
Units per dose by concentration
Pre-calculated U-100 units for each labeled dose at the concentrations compounding pharmacies most often use. These strengths are common but not standardized, so confirm the mg/ml on your own vial before drawing.
Semaglutide
| Dose | 2.5 mg/ml | 5 mg/ml | 10 mg/ml |
|---|---|---|---|
| 0.25 mg | 10 u | 5 u | 2.5 u |
| 0.5 mg | 20 u | 10 u | 5 u |
| 1 mg | 40 u | 20 u | 10 u |
| 1.7 mg | 68 u | 34 u | 17 u |
| 2.4 mg | 96 u | 48 u | 24 u |
Tirzepatide
| Dose | 10 mg/ml | 20 mg/ml |
|---|---|---|
| 2.5 mg | 25 u | 12.5 u |
| 5 mg | 50 u | 25 u |
| 7.5 mg | 75 u | 37.5 u |
| 10 mg | 100 u | 50 u |
| 12.5 mg | 125* u | 62.5 u |
| 15 mg | 150* u | 75 u |
* Exceeds a 1 ml (100-unit) syringe — use a 20 mg/ml vial or split the dose.
Is compounded GLP-1 legal in 2026?
Both drugs were on the FDA shortage list, which let pharmacies compound copies. Those shortages have since been resolved: enforcement discretion for tirzepatide ended in early 2025, and for semaglutide by May 2025.9 Outside a shortage, a 503A pharmacy may only compound these for an individual patient when the prescriber documents a clinically significant difference from the approved product. A standing preference, lower cost, or generic "personalization" does not meet that bar.
Safety notes
Confirm the concentration first
The FDA has reported overdoses, some needing hospitalization, traced to people measuring the wrong volume from a vial and confusing milligrams, milliliters, and syringe units.7 Read the mg/ml off your vial every time and have your prescriber check your calculation before the first injection.
mcg vs mg
A 2.5 mg dose is 2,500 mcg. Mixing the two units is a 1,000-fold error. This page and calculator work in mg, which is how GLP-1 doses are prescribed.
Salt forms are not equivalent
Some compounded semaglutide uses semaglutide sodium or acetate, which the FDA has flagged as different active ingredients from the base drug in Wegovy and Ozempic, and which have not been shown to be safe or effective.8 A milligram of a salt form is not necessarily a milligram of the same drug.
Frequently asked questions
How do I calculate units for compounded semaglutide or tirzepatide?
Divide your dose in mg by your vial concentration in mg/ml, then multiply by 100 for units on a U-100 insulin syringe. Example: a 2.5 mg tirzepatide dose from a 10 mg/ml vial is 0.25 ml, which is 25 units. The concentration is set by how the vial was mixed, so always read it off your own label.
Why does the concentration matter so much?
Compounded GLP-1 strengths are not standardized. The same 50 units delivers 5 mg from a 10 mg/ml vial but 10 mg from a 20 mg/ml vial. Using the wrong concentration is the most common cause of compounded GLP-1 overdose, so the first step is always confirming the mg/ml printed on your vial.
Is the dose the same as Ozempic, Wegovy, Mounjaro, or Zepbound?
The mg amounts usually mirror the branded titration schedules, but compounded products are not FDA-approved and have not been evaluated for potency, purity, or safety. Some compounded semaglutide also uses salt forms (semaglutide sodium or acetate) that the FDA has flagged as different active ingredients from the base drug in the approved products.
What is the standard semaglutide titration schedule?
Per the Wegovy label: 0.25 mg weekly for weeks 1 to 4, 0.5 mg for weeks 5 to 8, 1 mg for weeks 9 to 12, 1.7 mg for weeks 13 to 16, then 2.4 mg from week 17 onward. Each step lasts at least 4 weeks, and 1.7 mg is an accepted maintenance dose if 2.4 mg is not tolerated.
What is the standard tirzepatide titration schedule?
Per the Zepbound label: start at 2.5 mg weekly for 4 weeks, increase to 5 mg, then increase in 2.5 mg steps no sooner than every 4 weeks as needed, up to a maximum of 15 mg weekly. Common maintenance doses are 5, 10, and 15 mg.
Is it legal to get compounded semaglutide or tirzepatide in 2026?
The FDA shortages that allowed wide compounding have ended (tirzepatide enforcement wound down in early 2025, semaglutide by May 2025). Outside a shortage, a 503A pharmacy can only compound them for an individual patient when a prescriber documents a clinically significant difference from the approved product. Personalization and cost are not, by themselves, a qualifying reason.
Calculator
Semaglutide calculator
Calculator
Tirzepatide calculator
References
- Wegovy (semaglutide) injection — FDA Prescribing Information, §2.2 (titration) and §12.3 (pharmacokinetics). accessdata.fda.gov
- Ozempic (semaglutide) injection — FDA Prescribing Information, §2.2 and §12.3. accessdata.fda.gov
- Zepbound (tirzepatide) injection — FDA Prescribing Information, §2.1 (dosing) and §3 (strengths). accessdata.fda.gov
- Mounjaro (tirzepatide) injection — FDA Prescribing Information, §2.1 and §12.3. accessdata.fda.gov
- Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384(11):989–1002. doi:10.1056/NEJMoa2032183.
- Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med. 2022;387(3):205–216. doi:10.1056/NEJMoa2206038.
- FDA. Dosing errors associated with compounded injectable semaglutide products (Jul 2024). fda.gov
- FDA. Medications Containing Semaglutide Marketed for Type 2 Diabetes or Weight Loss (semaglutide sodium/acetate warning). fda.gov
- FDA. FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize (shortage resolution dates). fda.gov
This calculator is educational and is not medical advice. Compounded semaglutide and tirzepatide are not FDA-approved and have not been evaluated by the FDA for safety, effectiveness, or quality; concentrations and formulations vary by pharmacy. Always confirm your vial's concentration and your exact dose against the label, and have your prescriber verify your calculation before injecting. Read the full disclaimer.