Water volume for a 5 mg or 10 mg semaglutide vial, the concentration each volume gives and the U-100 units for the Wegovy label amounts from 0.25 mg to 7.2 mg.
Semaglutide is a GLP-1 receptor agonist, approved in the United States as Ozempic and Wegovy (injections) and Rybelsus and Wegovy tablets (oral). Every approved injectable is a solution in a pen or syringe; none is a powder, and no semaglutide label describes reconstitution. The lyophilized semaglutide vial that this page is about is a research-market presentation, sold in 5 mg and 10 mg sizes on the calculator preset for this site, and its only sourced figures are the amounts on the approved label and in the trials. This page reports the arithmetic for those vials and sets the label amounts beside it. It recommends nothing.
The semaglutide calculator runs the same sums for any vial and any volume; the semaglutide dosage page reports the figures and their sources in depth; the reconstitution hub indexes every compound.
The arithmetic in one line
Concentration in mg/mL is the vial amount divided by the water volume. Units on a U-100 syringe are the amount in milligrams divided by the concentration, times 100, because a U-100 syringe holds 100 units in 1 mL and each small notch on a standard 1 mL insulin syringe is 1 unit (MedlinePlus, "Giving an insulin injection", reviewed 2024-07-21).
Water volume per vial size
| Vial |
1 mL of water |
2 mL of water |
3 mL of water |
| 5 mg |
5 mg/mL |
2.5 mg/mL |
1.67 mg/mL |
| 10 mg |
10 mg/mL |
5 mg/mL |
3.33 mg/mL |
Units for the label amounts
The amounts are the Wegovy label's: 0.25 mg once weekly for weeks 1 to 4, then 0.5 mg, 1 mg and 1.7 mg in four-week steps, then a maintenance dosage of 1.7 or 2.4 mg once weekly, with an option to escalate to 7.2 mg for weight reduction (DailyMed, label revised 06/2026, read 2026-09-18). They appear here as the figures a reader meets in the sources, not as a plan.
| Concentration |
0.25 mg |
0.5 mg |
1 mg |
1.7 mg |
2.4 mg |
7.2 mg |
| 1.67 mg/mL |
15 units |
30 |
60 |
102 |
144 |
432 |
| 2.5 mg/mL |
10 |
20 |
40 |
68 |
96 |
288 |
| 3.33 mg/mL |
7.5 |
15 |
30 |
51 |
72 |
216 |
| 5 mg/mL |
5 |
10 |
20 |
34 |
48 |
144 |
| 10 mg/mL |
2.5 |
5 |
10 |
17 |
24 |
72 |
Anything over 100 units exceeds one U-100 syringe; a fraction of a unit falls between the marks of a 1-unit syringe. Semaglutide sits in an awkward middle: its label amounts run from a quarter of a milligram to more than seven, a 29-fold range, and no single concentration reads every one of them well. At 10 mg/mL the 0.25 mg step is 2.5 units and the 7.2 mg amount a comfortable 72; at 2.5 mg/mL the 0.25 mg step is a plain 10 units and 7.2 mg is 288, three syringes. That is a property of the label's range, not of any vial.
The 5 mg vial
The most searched question is what volume goes into a 5 mg vial. Any volume that dissolves the powder gives a valid solution; the volume sets only the concentration. At 1 mL the vial is 5 mg/mL and 0.25 mg is 5 units; at 2 mL it is 2.5 mg/mL and 0.25 mg is 10 units; at 3 mL it is 1.67 mg/mL and 0.25 mg is 15 units. Whatever the volume, a 5 mg vial holds twenty 0.25 mg amounts, ten 0.5 mg amounts, five 1 mg amounts or two 2.4 mg amounts with 0.2 mg left over, and it cannot hold a single 7.2 mg amount. A 10 mg vial doubles every count.
What the approved product's own numbers show
The approved pens are a check on any calculation because their volumes are printed on the label. Wegovy single-dose pens deliver 0.25, 0.5 and 1 mg in 0.5 mL, which is 0.5, 1 and 2 mg/mL, and 1.7, 2.4 and 7.2 mg in 0.75 mL, which is 2.27, 3.2 and 9.6 mg/mL; the FlexTouch pen holds 9.6 mg in 3 mL at 3.2 mg/mL and delivers four 2.4 mg doses (DailyMed, read 2026-09-18). The approved products therefore span 0.5 to 9.6 mg/mL, and the research-vial band in the tables above, 1.67 to 10 mg/mL, sits inside the upper part of it. The 2.4 mg pen's 0.75 mL would read as 75 units on a U-100 syringe; a 10 mg vial in 3 mL puts the same 2.4 mg at 72 units, which is the kind of agreement that tells a reader the arithmetic is right.
Mixing steps, as labels describe them
No semaglutide label describes mixing, because the approved injectables arrive dissolved. The steps that approved lyophilized peptide labels describe are consistent: the diluent is added to the vial, the vial is rolled gently rather than shaken, and the solution is inspected and used only if clear and free of particles (Egrifta SV label, DailyMed, revised 03/2024, read 2026-09-18). The general procedure, with supplies and order of operations, is Medibact's how to reconstitute peptides; this page does not repeat it.
Storage after mixing
The only labelled statements are for the approved solution: the Wegovy label keeps pens at 2 to 8 °C, allows 8 to 30 °C for up to 28 days before the cap is removed, and allows the FlexTouch pen 56 days at 15 to 30 °C after first use (DailyMed, read 2026-09-18); a mixed research vial has no label, and storage is covered by Medibact's how to store peptides.
Every label amount carries a route (subcutaneous), a frequency (once weekly), an escalation interval (four weeks) and a population (adults meeting the label's indications, and for the tablets a separate schedule that starts at 1.5 mg daily). STEP 1, the trial behind the 2.4 mg weight-reduction dose, ran 68 weeks against placebo (New England Journal of Medicine, 2021-03-18, PMID 33567185). The compounded-vial market that made "5 mg vial" a search term rested on FDA's shortage-period discretion, which ended on 2025-04-22 for 503A pharmacies and 2025-05-22 for 503B facilities after FDA declared the shortage resolved in February 2025 (Alston & Bird, 2025-03-12; National Community Pharmacists Association, 2025-03-13; both read 2026-09-18). The tables convert milligrams to units and do nothing else; the mechanism, evidence and sourcing belong to Medibact's semaglutide guide.
Sources and dates
Opened 2026-09-18: DailyMed, semaglutide search (nine records) and the Wegovy label (revised 06/2026); MedlinePlus, "Giving an insulin injection" (reviewed 2024-07-21); PubMed record 33567185 (STEP 1); the Egrifta SV label on DailyMed for the mixing description; the Alston & Bird advisory of 2025-03-12 and the National Community Pharmacists Association report of 2025-03-13; ClinicalTrials.gov v2 API (755 interventional registrations). Vial sizes are the ones the calculator preset uses.
This page does not recommend a dose, a water volume, a syringe or a schedule, and it does not say what any figure means for a particular person. It reports what the label and the trial state, and converts milligrams into millilitres and units.
