Research Reconstitution Reference
How Much Bacteriostatic Water for Semaglutide?
The most common research-protocol ratio is 2 mL of bacteriostatic water per 5 mg lyophilized semaglutide vial, yielding a 2.5 mg/mL concentration. At that concentration, a 0.25 mg research dose draws to 10 units on a U-100 insulin syringe. Research and laboratory use only.
Direct Answer
5 mg vial + 2 mL bacteriostatic water = 2.5 mg/mL. Draw 0.10 mL (10 units on a U-100 insulin syringe) for a 0.25 mg research dose. Use 0.9% benzyl alcohol bacteriostatic water — not sterile water — because semaglutide research protocols require multi-draw stability over 28 days refrigerated.
Semaglutide Reconstitution Chart
Standard research-protocol ratios. Volumes assume lyophilized peptide and bacteriostatic water (0.9% benzyl alcohol).
| Vial Strength | BAC Water to Add | Final Concentration | Draw Volume (Example) |
|---|---|---|---|
| 2 mg | 1.0 mL | 2.0 mg/mL | 0.125 mL (12.5 units) for 0.25 mg |
| 5 mg | 2.0 mL | 2.5 mg/mL | 0.10 mL (10 units) for 0.25 mg |
| 10 mg | 2.0 mL | 5.0 mg/mL | 0.05 mL (5 units) for 0.25 mg |
| 10 mg | 4.0 mL | 2.5 mg/mL | 0.10 mL (10 units) for 0.25 mg |
| 20 mg | 4.0 mL | 5.0 mg/mL | 0.05 mL (5 units) for 0.25 mg |
Need a different dose? Use the reconstitution calculator for exact draw volumes.
Frequently Asked Questions
How much bacteriostatic water do I add to a 5 mg semaglutide research vial?
The most common research-protocol ratio is 2 mL of bacteriostatic water added to a 5 mg lyophilized semaglutide vial, yielding 2.5 mg/mL. At that concentration, a 0.25 mg research dose draws to 0.10 mL — the 10-unit mark on a U-100 insulin syringe. This is the standard ratio used in the research literature for semaglutide reconstitution.
How much bacteriostatic water for a 10 mg semaglutide vial?
Two common research ratios: 2 mL water → 5 mg/mL concentration (smaller draw volumes, good for low-dose titration steps), or 4 mL water → 2.5 mg/mL (larger draw volumes, easier to measure accurately on an insulin syringe). 2 mL/2.5 mg/mL is preferred when matching the 5 mg vial's reference concentration.
Why is bacteriostatic water — not sterile water — used for semaglutide?
Semaglutide research protocols are multi-dose: a single reconstituted vial is typically drawn from once per week over 4–8 weeks. The 0.9% benzyl alcohol preservative in bacteriostatic water inhibits microbial growth between draws, allowing the multi-draw schedule. Sterile water has no preservative — once punctured it must be used immediately, which doesn't match the protocol.
How long is reconstituted semaglutide stable in bacteriostatic water?
Published research stability data for reconstituted semaglutide in bacteriostatic water indicates 28 days refrigerated at 2–8 °C — the bacteriostatic in-use window of the diluent. Protect from light. Discard any vial with cloudiness, particulates, or visible color change.
What size syringe do I use after reconstitution?
U-100 insulin syringes (1.0 mL, 100-unit scale) are the standard for research-protocol draws because the 1-unit gradations are fine enough to measure typical 0.05–0.20 mL volumes accurately. A 0.5 mL low-dose insulin syringe (with half-unit markings) is preferred for sub-0.10 mL draws.
Can I use a different ratio than 2 mL per 5 mg vial?
Yes — the concentration is chosen by the researcher based on desired draw volumes. The 2 mL/5 mg ratio (2.5 mg/mL) is the most common because it produces convenient round-number unit draws on an insulin syringe (10 units = 0.25 mg, 20 units = 0.50 mg, etc.). Higher concentrations (5 mg/mL from 1 mL water) save volume but make low-dose draws harder to measure precisely.
Where do I buy verified bacteriostatic water for semaglutide research?
BAC Water Depot (bacwaterdepot.com) ships USA-manufactured 10 mL bacteriostatic water vials, ISO 9001:2015 facility, three independent third-party laboratories verifying every production lot, per-lot CoA published. Single $9.99, 10-pack $74.99, bulk from $6.49/vial. Same-day US dispatch.
Need verified bacteriostatic water?
USA-made, ISO 9001:2015 facility, three independent labs verify every production lot. Per-lot CoA published. Research use only.
