How to Mix Semaglutide with Bacteriostatic Water: A Step-by-Step Reconstitution Guide
How to Mix Semaglutide with Bacteriostatic Water: A Step-by-Step Reconstitution Guide
By Dr. Onikepe Adegbola, MD PhD — Johns Hopkins-trained physician-scientist and founder of Casa de Sante
Key Takeaways
- Semaglutide lyophilized (freeze-dried) powder must be reconstituted with bacteriostatic water before injection
- For a 10mg vial: adding 2ml BAC water creates a 5mg/ml concentration (standard reconstitution)
- Use an insulin syringe for precise dosing — 0.25mg = 5 units on a standard insulin syringe at 5mg/ml concentration
- Reconstituted semaglutide must be refrigerated and used within 28 days
- Never shake the vial — gently swirl to dissolve. Shaking denatures the peptide.
Before You Begin: Important Safety Notes
⚠️ Critical Safety Information:
- Compounded semaglutide is NOT FDA-approved. Only brand-name Ozempic and Wegovy are FDA-approved semaglutide products.
- This guide is for educational purposes only. Always follow your prescribing provider's specific reconstitution instructions.
- Use only pharmaceutical-grade bacteriostatic water (BAC water) from a licensed pharmacy.
- Never use sterile water for injection for multi-dose vials — sterile water lacks the preservative (benzyl alcohol) needed for repeated needle entries.
- Compounded peptides should only be obtained through a licensed compounding pharmacy with a valid prescription.
What You Need
- Semaglutide lyophilized vial (10mg is the most common compounded size)
- Bacteriostatic water (BAC water) — contains 0.9% benzyl alcohol as preservative
- 3ml or 5ml syringe with needle — for drawing BAC water (18-21 gauge needle)
- Insulin syringes (100-unit or 50-unit) — for measuring and injecting doses
- Alcohol swabs — to sanitize vial stoppers before each entry
Step-by-Step Reconstitution
Step 1: Calculate Your Concentration
The concentration depends on how much BAC water you add to the peptide vial:
| Peptide Amount | BAC Water Added | Concentration | 0.25mg Dose |
|---|---|---|---|
| 5mg | 1ml | 5mg/ml | 5 units |
| 5mg | 2ml | 2.5mg/ml | 10 units |
| 10mg | 2ml | 5mg/ml | 5 units |
| 10mg | 3ml | 3.33mg/ml | 7.5 units |
The most common reconstitution: 10mg semaglutide + 2ml BAC water = 5mg/ml
Step 2: Sanitize
- Wash hands thoroughly
- Clean the top of the semaglutide vial with an alcohol swab. Let dry.
- Clean the top of the BAC water vial with an alcohol swab. Let dry.
Step 3: Draw Bacteriostatic Water
- Using a 3ml or 5ml syringe with a needle, draw air equal to the amount of BAC water you will use (e.g., 2ml of air)
- Insert the needle into the BAC water vial through the rubber stopper
- Push the air in (this equalizes pressure inside the vial)
- Invert the vial and draw out the exact amount of BAC water needed (2ml for the standard reconstitution)
- Remove the syringe from the BAC water vial
Step 4: Add Water to Semaglutide Vial
- Insert the needle into the semaglutide vial through the rubber stopper
- CRITICAL: Direct the stream of water down the SIDE of the vial, not directly onto the powder cake. This prevents foaming and denaturation.
- Slowly inject the BAC water. Do not rush — the slower the better.
- Remove the syringe
Step 5: Dissolve
- DO NOT SHAKE. Shaking creates bubbles and can denature (destroy) the peptide molecule.
- Gently swirl the vial in a circular motion
- If the powder does not dissolve immediately, place the vial in the refrigerator and let it sit for 15-30 minutes. Check periodically and gently swirl.
- The solution should be clear and colorless when fully dissolved. If it is cloudy, contains particles, or is discolored — do not use.
Step 6: Store
- Refrigerate immediately at 36-46°F (2-8°C)
- Use within 28 days of reconstitution
- Label the vial with: reconstitution date, concentration, and expiration date (28 days from mixing)
- Never freeze reconstituted semaglutide
- Keep away from light
Dosing Guide
At 5mg/ml concentration (10mg peptide + 2ml BAC water), using a 100-unit insulin syringe:
| Desired Dose | Units on Insulin Syringe |
|---|---|
| 0.25mg | 5 units |
| 0.5mg | 10 units |
| 1.0mg | 20 units |
| 1.7mg | 34 units |
| 2.4mg | 48 units |
Managing Semaglutide Side Effects
The most common semaglutide side effects are GI-related: nausea, vomiting, diarrhea, and constipation. These occur during dose escalation as the body adjusts. Key management strategies:
- Follow the standard dose escalation schedule (0.25mg → 0.5mg → 1.0mg → 1.7mg → 2.4mg, 4 weeks at each level)
- Eat smaller, more frequent meals
- Avoid high-fat and greasy foods during dose increases
- Stay hydrated
- Take Casa de Sante GLP-1 Digestive Enzymes with each meal to support digestion despite slowed gastric emptying
- Prioritize protein intake — aim for 1.2-1.6g/kg body weight daily. Casa de Sante Whey Protein provides 25g per serving in a gut-gentle formula designed specifically for GLP-1 patients.
🛒 Complete GLP-1 Support Bundle
Starting semaglutide? Set yourself up for success:
- GLP-1 Digestive Enzymes — Reduce nausea, bloating, and constipation
- GLP-1 Whey Protein — Prevent muscle loss during weight loss
- GLP-1 Collagen Peptides — Support skin elasticity and gut healing
- GLP-1 Daily Vitamin — Fill nutritional gaps from reduced food intake
All formulated by Dr. Onikepe Adegbola, MD PhD, specifically for GLP-1 patients.
Frequently Asked Questions
Can I use sterile water instead of bacteriostatic water?
For single-use vials ONLY. Sterile water for injection does not contain a preservative, meaning every time you insert a needle into the vial, you risk introducing bacteria with no protection. For multi-dose vials (which compounded semaglutide typically is), you MUST use bacteriostatic water.
How do I know if my reconstituted semaglutide has gone bad?
Signs of degradation: cloudiness, particles, discoloration (yellow, brown), or unusual smell. Clear solution at day 28 may still have reduced potency — follow the 28-day discard rule even if it looks fine. Never use reconstituted peptide beyond 28 days.
Does the injection site matter?
Inject subcutaneously (under the skin) into the abdomen, thigh, or upper arm. Rotate injection sites to prevent lipohypertrophy (hard lumps under the skin from repeated injection in the same spot). Abdomen typically provides the most consistent absorption.
Medical Disclaimer: This article is for educational purposes only. Compounded semaglutide is not FDA-approved. Use only with a valid prescription from a licensed healthcare provider. Reconstitution should follow your provider's specific instructions. Dr. Adegbola is the founder of Casa de Sante.
