GLP-1 Calculators
Last updated: June 2026
1mg Semaglutide: How Many Units After Reconstitution
The number of syringe units in a 1mg semaglutide dose depends entirely on how your vial was reconstituted, not on the dose alone. This guide shows the exact mg-to-units math for the 1mg step at the concentrations compounded vials are most often mixed to.
1mg semaglutide: how many units depends on concentration
There is no single answer to "1mg semaglutide, how many units" until you know the concentration of your vial in milligrams per millilitre (mg/mL). The dose is fixed at 1mg, but units measure volume on the syringe, and the volume that carries 1mg changes with concentration.
On a standard U-100 insulin syringe, 1 unit = 0.01 mL (100 units per mL). So the number of units for any dose is just the volume in mL multiplied by 100. To get the volume, divide your dose in mg by the concentration in mg/mL. This is the same arithmetic explained in mg, mcg, mL and units explained.
The 1mg step is a common maintenance dose reached partway through a standard semaglutide titration. For context on where 1mg sits in the schedule, see the semaglutide titration schedule.
The formula for 1mg in units
Two steps convert any milligram dose into U-100 syringe units:
- Volume (mL) = dose (mg) ÷ concentration (mg/mL)
- Units = volume (mL) × 100
Combined into one line for a U-100 syringe:
Units = (dose in mg ÷ concentration in mg/mL) × 100
Example
A vial reconstituted to 5 mg/mL, dosing 1mg:
Volume = 1 mg ÷ 5 mg/mL = 0.2 mL
Units = 0.2 mL × 100 = 20 units
So 1mg of semaglutide is drawn to the 20-unit mark on a U-100 syringe at this concentration.
Because units track volume and not the drug itself, the same 20-unit mark would hold a completely different milligram amount if the vial were mixed to a different strength. That is why 10 units does not always mean the same dose.
1mg semaglutide units at common concentrations
The table below applies the formula to the concentrations compounded semaglutide vials are most often reconstituted to. All values are for a 1mg dose on a U-100 syringe.
| Concentration (mg/mL) | Volume for 1mg (mL) | Units (U-100) |
|---|---|---|
| 2 mg/mL | 0.50 mL | 50 units |
| 2.5 mg/mL | 0.40 mL | 40 units |
| 4 mg/mL | 0.25 mL | 25 units |
| 5 mg/mL | 0.20 mL | 20 units |
| 10 mg/mL | 0.10 mL | 10 units |
Notice the pattern: doubling the concentration halves the units. A more concentrated vial means a smaller, harder-to-read volume on the syringe for the same 1mg.
Working out your concentration from the vial and BAC water
If you do not already know your concentration, calculate it from the total milligrams in the vial and the volume of bacteriostatic water you added:
Concentration (mg/mL) = total mg in vial ÷ mL of BAC water added
For more detail on this step, see why the water amount changes syringe units and what reconstitution means.
Example
A 5mg vial reconstituted with 1 mL of BAC water:
Concentration = 5 mg ÷ 1 mL = 5 mg/mL
1mg dose = (1 ÷ 5) × 100 = 20 units
Example
A 5mg vial reconstituted with 2.5 mL of BAC water:
Concentration = 5 mg ÷ 2.5 mL = 2 mg/mL
1mg dose = (1 ÷ 2) × 100 = 50 units
Same vial, same 1mg dose, but 50 units instead of 20 because more water was added.
1mg units for typical 5mg and 10mg vials
Compounded semaglutide is commonly supplied as 5mg or 10mg vials. The units for a 1mg dose depend on how much BAC water was added to each.
| Vial | BAC water added | Concentration | 1mg dose (units) |
|---|---|---|---|
| 5 mg | 1.0 mL | 5 mg/mL | 20 units |
| 5 mg | 2.0 mL | 2.5 mg/mL | 40 units |
| 5 mg | 2.5 mL | 2 mg/mL | 50 units |
| 10 mg | 1.0 mL | 10 mg/mL | 10 units |
| 10 mg | 2.0 mL | 5 mg/mL | 20 units |
Always confirm the milligram strength printed on your own vial and the exact water volume you measured. If either is uncertain, do not estimate the dose. The semaglutide product label and your prescriber define the correct dose; this page only converts a known mg dose into units.
Check your number against the calculator
Manual arithmetic is easy to get right for round numbers like 1mg, but a second check is worth doing before you draw. Enter your vial strength, BAC water volume and a 1mg dose into the Semaglutide Units Calculator and confirm it matches the unit value you calculated by hand.
If your titration moves off the 1mg step later, the same calculator handles other doses such as 1.7mg or 2.4mg. For the smaller starting dose, see how many units is 0.25mg semaglutide.
FAQs
How many units is 1mg of semaglutide?
It depends on the concentration. At 5 mg/mL it is 20 units; at 2 mg/mL it is 50 units; at 10 mg/mL it is 10 units, all on a U-100 syringe. Use the formula (1 ÷ concentration in mg/mL) × 100 to get your exact number.
Why do different sources give different units for 1mg semaglutide?
Because they assume different reconstitution concentrations. Units measure volume on the syringe, not the milligrams of drug. A vial mixed to a higher mg/mL needs fewer units for the same 1mg dose. Always calculate from your own vial's concentration.
What is 1mg semaglutide in units at 2.5 mg/mL?
At 2.5 mg/mL, 1mg occupies 0.4 mL, which is 40 units on a U-100 syringe. The math is 1 mg ÷ 2.5 mg/mL = 0.4 mL, then 0.4 × 100 = 40 units.
Does this work for a 0.5 mL or U-40 syringe?
The units shown here assume a U-100 syringe, where 1 unit = 0.01 mL. A 0.5 mL U-100 syringe uses the same unit markings, just with a shorter barrel. A U-40 syringe has different markings and is not interchangeable; do not use the U-100 values with it.
Is 1mg the right semaglutide dose for me?
This page does not recommend a dose. 1mg is a fixed maintenance step in the standard semaglutide titration, but the dose appropriate for you is decided by your prescriber and the product label. This guide only converts a known mg dose into syringe units.
Read next
Semaglutide Units Calculator GuideSources
- U.S. Food and Drug Administration. WEGOVY (semaglutide) injection, prescribing information. DailyMed, National Library of Medicine. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ee06186f-2aa3-4990-a760-757579d8f77b.
- U.S. Food and Drug Administration. OZEMPIC (semaglutide) injection, prescribing information. DailyMed, National Library of Medicine. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=adec4fd2-6858-4c99-91d4-531f5f2a2d79.
- Pettus J, et al. Novel Concentrated Insulin Delivery Devices: Developments for Safe and Simple Dose Conversions. J Diabetes Sci Technol. 2016. PMC5505430. pmc.ncbi.nlm.nih.gov/articles/PMC5505430.
- Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384(11):989-1002. PMID 33567185. pubmed.ncbi.nlm.nih.gov/33567185.
This guide is for general educational purposes only and does not constitute medical advice. Always follow your prescriber's specific instructions.