How to use a semaglutide vial: overview
- Prepare your workspace — clean surface, 20-second handwash, all supplies gathered and inspected.
- Reconstitute the vial — add bacteriostatic water slowly down the inside wall; swirl gently until clear; note the date.
- Calculate and draw your dose— dose (mg) ÷ concentration (mg/mL) = volume (mL); confirm with your clinician.
- Inject subcutaneously as directed — abdomen, upper outer thigh, or upper outer arm; rotate sites weekly; dispose needle immediately in a sharps container.
- Store the reconstituted vial— refrigerate at 2–8 °C; use within your pharmacy’s beyond-use date.
What comes in a compounded semaglutide vial kit?
Compounded semaglutide is typically shipped as a lyophilized (freeze-dried) powder in a sealed glass vial. It arrives alongside a vial of bacteriostatic water — the sterile, preserved diluent you’ll use to reconstitute it — plus alcohol swabs, syringes, and needles. Some pharmacies ship pre-reconstituted liquid; if yours does, skip the reconstitution steps below and follow the storage guidance your pharmacy provides.
You’ll also receive a dosing schedule from your clinician. The starting dose for most weight-management protocols is low, typically 0.25 mg per week, with gradual titration upward over several weeks based on tolerability. Do not self-adjust your dose.
Step 1: Prepare your workspace
Clean the surface you’ll work on. Wash your hands thoroughly with soap and water for at least 20 seconds, then dry them with a clean towel. Gather everything before you start: the semaglutide vial, bacteriostatic water vial, two syringes (one to transfer the water, one for the final injection, or a single insulin syringe if that’s what your pharmacy includes), alcohol swabs, and your sharps container.
Inspect both vials. The semaglutide powder should appear white to off-white with no visible contamination. The bacteriostatic water should be clear and colorless. If either vial looks off, contact your pharmacy before proceeding.
Step 2: Reconstitute the semaglutide vial
Swab the rubber stopper of the bacteriostatic water vial with an alcohol swab and let it dry for 30 seconds. Draw the prescribed volume of bacteriostatic water into your syringe — your pharmacy or clinician will specify how many mL to use. This volume determines your final concentration, so precision here affects every dose you draw afterward.
Swab the stopper on the semaglutide vial and let it dry. Insert the needle and slowly push the bacteriostatic water down the inside wall of the vial — not directly onto the powder. Injecting directly onto the lyophilized powder can degrade the peptide. Once all the water is in, remove the syringe and gently swirl the vial between your fingers for 20–30 seconds. Never shake the vial. The solution should become clear with no visible particulates. If it remains cloudy or you see floating particles, do not inject — contact your pharmacy.
Note the date and time of reconstitution on the vial with a label or marker. Most 503A pharmacies specify a beyond-use date (BUD) for reconstituted semaglutide — commonly 28 days refrigerated. Never use the solution past that window.
Add the water down the inside wall and swirl — never spray it onto the powder, and never shake — because rough handling can degrade the peptide.
Step 3: How do you calculate and draw your dose from a semaglutide vial?
Your dose is expressed in milligrams (mg). Your concentration — determined by how much bacteriostatic water you added — is in mg per mL. To find the volume to draw:
Volume (mL) = Dose (mg) ÷ Concentration (mg/mL)
Example: if you added 2 mL of bacteriostatic water to a 5 mg vial, your concentration is 2.5 mg/mL. A 0.25 mg dose would require 0.1 mL (10 units on a 100-unit insulin syringe). Confirm this math with your clinician or pharmacist before your first injection.
Swab the vial stopper, let it dry, insert your injection syringe at an angle, invert the vial, and slowly draw back the plunger to the calculated volume. Check for air bubbles — tap the syringe and push them out gently, then re-draw to your mark.
Step 4: Inject subcutaneously
Compounded semaglutide is given as a subcutaneous injection — into the fatty tissue just beneath the skin, not into muscle. Common sites are the lower abdomen (at least two inches from the navel), the upper outer thigh, or the upper outer arm. Rotate sites with each weekly injection to minimize injection-site reactions such as redness, bruising, or nodules.
Swab the injection site with an alcohol swab and allow it to dry completely — injecting through wet alcohol can sting and may increase irritation. Pinch a fold of skin, insert the needle at a 45–90 degree angle depending on body composition (leaner individuals typically use 45°), and inject slowly. Withdraw the needle smoothly, apply gentle pressure with a clean swab if needed, and dispose of the needle immediately in your sharps container. Never recap a used needle.
How do you store a semaglutide vial before and after reconstitution?
Before reconstitution: Store the lyophilized powder vial refrigerated at 36–46°F (2–8°C). Keep it away from light. Do not freeze. Most vials are stable refrigerated until the expiration date printed on the label.
After reconstitution:Keep the solution refrigerated at all times. Do not freeze — freezing a reconstituted peptide solution can damage the molecule and render it ineffective. Use within the beyond-use date your pharmacy assigns. If you’re traveling, keep the vial in an insulated case with a cold pack for trips under 24 hours; for longer travel, check with your clinician.
Frequently asked questions about semaglutide vial use
How do I reconstitute a semaglutide vial?
Add bacteriostatic water slowly down the side of the vial (never directly onto the lyophilized powder). Swirl gently — never shake — until fully dissolved. The resulting solution should be clear. Your clinician will specify the exact volume of bacteriostatic water to use based on your prescribed dose.
Where do I inject compounded semaglutide?
Subcutaneous injection into the abdomen (at least 2 inches from the navel), upper outer thigh, or upper outer arm. Rotate sites each week to reduce injection-site reactions.
How do I calculate my dose from a semaglutide vial?
Your clinician or pharmacy will provide a concentration (e.g., 5 mg/mL) and a target dose in mg. Divide dose (mg) by concentration (mg/mL) to get the volume in mL you draw. Always confirm the calculation with your prescribing clinician before injecting.
How should a semaglutide vial be stored?
Before reconstitution, store lyophilized vials refrigerated (36–46°F / 2–8°C) and away from light. After reconstitution, keep refrigerated and use within the window specified by your 503A compounding pharmacy — typically 28 days. Never freeze a reconstituted vial.
Is compounded semaglutide FDA-approved?
No. Compounded semaglutide is not FDA-approved. It is prepared by licensed 503A compounding pharmacies and requires a clinician prescription. It is not the same as branded Ozempic or Wegovy, and no efficacy or safety equivalence to those branded products should be assumed.
What should I do if I miss a weekly semaglutide dose?
If fewer than 5 days have passed since your scheduled day, inject as soon as you remember. If more than 5 days have passed, skip that dose and resume your normal schedule the following week. Never double-dose. Always follow your clinician's specific instructions.
Why does the compounding source matter?
Not all compounded semaglutide is created equal. PepScribe works exclusively with licensed 503A compounding pharmacies based in the USA. No hidden overseas supply chain. Every vial ships from a US-licensed pharmacy under clinician oversight — not from an international vendor or an unlicensed reseller.
Gray-market sources present real risks: inaccurate dosing, contamination, unknown excipients, and zero recourse when something goes wrong. If the price seems dramatically lower than a licensed pharmacy, that disparity usually has a source.
If you’re interested in a clinician-supervised semaglutide protocol, the path starts with a short intake assessment — a licensed clinician reviews your goals and health history and determines whether compounded semaglutide is appropriate for you. See also our semaglutide program overview.