Reconstitution calculator
Get your dose right, every time.
Reconstitution volumes, dose-per-mark, and doses per vial - one tool, no spreadsheets. Runs entirely in your browser, no account needed.
Choose a calculator:
Enter your values
250 micrograms = 0.250 mg (1000 mcg = 1 mg)
Most common is U-100 (100 units = 1 ml). U-50 marks 50 units/ml, U-30 marks 30.
Your injection volume
10
units on a U-100 syringe (0.100 ml)
Concentration
2,500 micrograms per ml
= 2.50 mg per ml
5,000 micrograms (5 mg) total in 2 ml water
Doses per vial
20 doses
at 250 micrograms (0.250 mg) per dose
From a 5 mg vial
Mixing 5 mg with 2 ml of bacteriostatic water gives 2,500 mcg/ml. A 250 micrograms dose is 0.100 ml - that's 10 units on a U-100 syringe. The vial holds 20 full doses.
Reconstitution tips
Adding water
Let the bacteriostatic water run slowly down the inside of the vial - never straight onto the powder - and let it dissolve on its own. No shaking.
Storage
After mixing, keep the vial refrigerated at 2-8 C. Stored properly, most peptides hold up for roughly 4-6 weeks.
Syringe selection
U-100 is the everyday standard. For very small draws, a U-50 or U-30 scale spreads the same volume across larger markings for finer reading.
Measuring accuracy
More water = easier measuring but a bigger injection. Less water = concentrated mix and a smaller shot. Pick the volume that puts your dose on a clean mark.
Save your reconstitution math - free account
Keep every vial, dose, and protocol in one place. Free forever, no card needed.
Track your peptide journey
Log doses, watch weight and mood trends, and see your progress in the Peptide Tracker.
How to reconstitute a peptide
Reconstitution means adding liquid to a lyophilized peptide powder so each syringe mark maps to a predictable amount. These steps are educational, not medical instructions.
- Gather your supplies: lyophilized peptide vial, bacteriostatic water, sterile mixing syringe, alcohol swabs, insulin syringe, and a sharps container.
- Bring everything to room temperature Cold liquid can make the powder dissolve slowly and can create condensation on the vial.
- Measure the water. Pick your total volume first, then pull exactly that much into the mixing syringe.
- Run the water down the inside glass wall Aim at the glass, not the powder. Let the water slide down slowly to reduce foaming.
- Let it dissolve by itself. A gentle swirl is fine; shaking is not. Agitation can break peptide chains and whip up foam that is hard to draw.
- Inspect the result. A finished solution is clear and colorless. Persistent cloudiness or floating particles mean the vial should be discarded.
- Refrigerate it Store the mixed vial cold, upright, and away from light. Write the reconstitution date on the label.
Quick reference chart
The same vial at different water volumes. Your dose never moves - only the injection size changes.
| Vial size | Water added | Concentration | 250 mcg dose | 500 mcg dose |
|---|---|---|---|---|
| 5 mg | 2 mL | 2.5 mg/mL | 10 units | 20 units |
| 5 mg | 1 mL | 5 mg/mL | 5 units | 10 units |
| 10 mg | 2 mL | 5 mg/mL | 5 units | 10 units |
| 10 mg | 1 mL | 10 mg/mL | 2.5 units | 5 units |
Units shown on a U-100 insulin syringe (100 units = 1 mL). Use the calculator above for your exact vial and dose.
The math, in plain English
The calculator is just two ratios.
Common mistakes to avoid
- Shaking the vial. Swirl gently instead - agitation can degrade the peptide and creates foam that is difficult to draw.
- Spraying water straight onto the powder. Aim the stream at the glass wall and let it run down slowly.
- Using plain sterile water for a multi-dose vial. Without a preservative, a vial you keep drawing from over weeks can grow bacteria - bacteriostatic water exists for exactly this reason.
- Getting the dilution wrong. Too much water leaves you with a large, awkward injection; too little makes tiny doses nearly impossible to measure precisely.
- Using a cloudy solution. A properly mixed peptide is clear. Cloudiness or visible particles mean the vial should be thrown away.
Frequently asked questions
How much bacteriostatic water should I add to a 10 mg vial?
Any amount works - water only sets the concentration, never your dose. A popular choice is 2 mL, which makes 5 mg/mL and puts a 250 mcg dose at 5 units on a U-100 syringe.
Can I use sterile water or saline instead of bacteriostatic water?
For any vial you will draw from more than once, use bacteriostatic water. Plain sterile water and saline have no preservative, so they only suit a single-use, same-day mix.
How long does a reconstituted peptide stay usable?
Refrigerated at 2-8 C, most peptides remain stable for about 4-6 weeks, though this varies by compound.
Why are doses given in units instead of mL?
Insulin syringes are printed in units. On a U-100 scale, 100 units = 1 mL.
Can I shake the vial so it dissolves faster?
No. Shaking can damage peptide chains and create foam. Gentle swirling or waiting is enough.
Educational use only. This information is aggregated from public research and community reports. It is not medical advice, and dosing details are descriptive, not recommendations. Always consult a qualified healthcare professional.