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Basics & Technique

How do I reconstitute a 5 mg semaglutide vial?

Updated 2026-05-03

Most 5 mg semaglutide vials get mixed with 2.5 mL of bacteriostatic water. That gives you 2 mg per mL. On a U-100 insulin syringe, every 5 units equals 0.1 mg of semaglutide. So a 0.25 mg starter dose is 12.5 units. Pour the water down the side of the vial slowly. Do not shake. Roll it gently between your hands until the liquid is clear.

IfIf you only have 1 mL of bacteriostatic water on hand
Thenthen your final mix is 5 mg per mL, and 5 units on a U-100 syringe equals 0.25 mg
IfIf the powder still has chunks after rolling for a minute
Thenthen let the vial sit upright at room temperature for 5 to 10 minutes and roll again
IfIf the liquid looks cloudy or has floaters after mixing
Thenthen stop and do not inject - reach out to your source for a replacement
IfIf you accidentally added 3 mL of bacteriostatic water instead of 2.5 mL
Thenthen your dose math changes - your new mix is 1.67 mg per mL, so a 0.25 mg dose is 15 units on a U-100 syringe
Key facts
  • 5 mg vial + 2.5 mL bacteriostatic water = 2 mg per mL final concentration
  • On a U-100 syringe at 2 mg per mL, 1 unit = 0.02 mg of semaglutide
  • Standard semaglutide titration is 0.25 mg weekly for 4 weeks, then 0.5 mg, then up
  • Bacteriostatic water contains 0.9% benzyl alcohol, which keeps the mix sterile for about 28 days
  • Refrigerate the reconstituted vial between 36 and 46 degrees Fahrenheit
  • Quick math: dose in mg, divided by the vial mg per mL, times 100, equals units on a U-100 syringe
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