Semaglutide reconstitution calculator and reference
Sometimes searched as GLP-3 (a common misspelling of GLP-1) and known by the brand names Ozempic and Wegovy.
Short answer: add 1 mL of bac water to a 3 mg Semaglutide vial. A 250 mcg amount then measures about 8.3 units on a 1 mL (U-100) insulin syringe.
To mix a 3 mg vial of Semaglutide, add about 1 mL of BAC water. Now each 1 mL of liquid holds 3 mg of peptide. So a 250 mcg dose is about 8.3 units on a 1 mL insulin syringe. Want a rounder number? Add a little more or a little less water.
What nobody knows
Semaglutide is an approved molecule, so its approved product has official labeling. That labeling, not this site, is the reference for amounts. But an unapproved research powder sold under the same name is a different thing. There is no assurance it is actually Semaglutide, that it is pure, or that the amount matches the label.
Semaglutide bac water calculator
= 0.25 mg
This is general reconstitution math for research and educational use only. BACwater.ai is not a medical company, and this is not medical advice. Always check your product's own paperwork and talk to your doctor before making any health decision. Read the full disclaimer.
What you cannot know about your vial
- You cannot see what is really inside. Independent testing in this market has found research powders that were mislabeled, weaker or stronger than the label, or contaminated. An unlabeled vial tells you nothing you can verify.
- “Research-grade” is not a standard. It is not a grade anyone checks. It does not promise that the powder is Semaglutide, that it is pure, or that the amount matches the label.
- No calculation fixes this. The math here is exact for the numbers you type. It cannot tell you whether the powder in your vial matches what is printed on it.
What is Semaglutide?
Semaglutide is a lab-made peptide. It is one of the most studied peptides for how the body handles food and weight. It works on a body signal called GLP-1 (a GLP-1 receptor agonist).
It is frequently reconstituted for research into metabolic and appetite pathways. Studied amounts start very low and increase slowly.
Metabolic peptides include the GLP-1 class (they act on a body signal called GLP-1, which is studied in research for its role in appetite and blood sugar pathways). They are often reconstituted for research. The amounts studied vary a lot, so working out the BAC water for your exact vial matters more here than almost anywhere.
What published research looked at
FDA-approved with large human clinical trials. FDA-approved (Ozempic, semaglutide injection).
The approved product's labeling: the reference for amounts, not this site.
- Tested on
- Human (FDA-approved labeling)
- Amount
- 0.25 mg to 2 mg (approved range)
- How often
- Once weekly
- How long
- Ongoing chronic use
- Route
- Subcutaneous
These are study details, not instructions. An amount given to animals cannot be turned into a safe amount for a person.
How much bac water for Semaglutide?
The chart below is a Semaglutide reconstitution chart: each common vial size, the bac water to add, and where a 250 mcgmeasurement lands on a 1 mL insulin syringe. Use the calculator above for your exact vial and the amount you want to measure.
| Vial amount | Bac water to add | Concentration | Amount to measure | Syringe units |
|---|---|---|---|---|
| 3 mg | 1 mL | 3 mg/mL | 250 mcg | 8.3 units |
| 5 mg | 2 mL | 2.5 mg/mL | 250 mcg | 10 units |
| 10 mg | 3 mL | 3.33 mg/mL | 250 mcg | 7.5 units |
The amount in the “Amount to measure” column is an example chosen so the math is easy to follow. It is not a recommended amount, and this site does not recommend how much to use. Units assume a U-100 insulin syringe (100 units = 1 mL). Always confirm the amount printed on your own vial.
How to reconstitute Semaglutide
- 1Gather your supplies
Wash your hands and lay out your Semaglutide vial, a vial of bacteriostatic water, an insulin syringe, and alcohol prep pads on a clean surface.
- 2Swab both vial tops
Wipe the rubber stopper of both the peptide vial and the bacteriostatic water vial with separate alcohol prep pads. Let them air dry.
- 3Draw the bacteriostatic water
For a 3 mg vial, draw about 1 mL of bacteriostatic water. Use the calculator on this page to match your exact vial strength.
- 4Add water to the peptide vial
Insert the needle at an angle and let the water run slowly down the inside wall of the vial. Do not spray it directly onto the powder.
- 5Swirl gently
Roll or swirl the vial between your palms until the powder fully dissolves. Roll it, do not shake it, if your product's instructions say so. The solution should look clear.
- 6Label and refrigerate
Label the vial with the peptide name, the date mixed, and the expiration date, then refrigerate it immediately.
Storage and shelf life
Keep in the fridge, following your product's instructions. Research amounts vary widely and are usually very small. Confirm the exact milligram strength printed on your vial before calculating. Once you add bac water, the peptide slowly breaks down, so refrigerate the vial and discard it if the solution turns cloudy or develops particles.
Semaglutide reconstitution FAQ
Keep reading about Semaglutide
- Peptide GuideHow to Reconstitute Semaglutide
What You Need Semaglutide vial (common strengths: 3 mg, 5 mg) Bacteriostatic water (BAC water) Insulin syringe (0.5 mL or 1 mL) Alcohol prep pads Step by Step I
- SafetyWhat Happens if You Add Too Much BAC Water
Short Answer Adding too much BAC water does not ruin the peptide. It simply dilutes the concentration, meaning you will need to draw a larger volume per dose. W
- SafetyHow to store reconstituted peptides
Storage Basics Refrigerate all reconstituted peptides at 36 to 46 °F (2 to 8 °C). Store vials upright in the door shelf or a dedicated container, away from the
- GuideWhat you cannot know about your vial
The math is exact for the numbers you type, but it cannot tell you what is really in the powder. What no calculation can verify.
- SafetyBAC water and peptide shelf life
How long reconstituted peptides and opened bac water last, why refrigeration and clean technique both matter, and when to discard a vial.
Related peptides
Compare Semaglutide with Tirzepatide side by sideReferences
Primary sources for the facts on this page. We cite regulatory and peer-reviewed authorities rather than secondary blogs.
- Bacteriostatic Water for Injection, USP - prescribing information · U.S. FDA labeling via DailyMed (NIH / NLM)Defines bacteriostatic water as sterile water with 0.9% benzyl alcohol added as a bacteriostatic preservative, supplied in a multiple-dose container for diluting or dissolving drugs; contraindicated in neonates.
- Benzyl alcohol (Compound CID 244) · NIH PubChem, National Library of MedicineChemical identity, properties, and safety data for benzyl alcohol, the bacteriostatic preservative in BAC water.
The Plan Builder turns these numbers into a printable, step-by-step plan. You can also read how reconstitution works, brush up on the bac water calculator, or start from the complete bac water guide.