Reconstitution calculator
Get your dose right, every time.
Calculate reconstitution volumes, dose-per-mark, and half-life timing - built into one tool. No spreadsheets.
Choose a calculator:
Reconstitution
Dosing, dilution & half-life
Blend Calculator
Multi-peptide dosing
Enter Your Values
250 micrograms = 0.250 mg(1000 mcg = 1 mg)
Most common is U-100 (100 units = 1ml)
Your Injection Volume
Concentration
= 2.50 mg per ml
5,000 micrograms (5.0 mg) total in 2 ml water
Doses per Vial
at 250 micrograms (0.250 mg) per dose
From a 5 mg vial
Reconstitution Tips
Adding Water
Slowly add bacteriostatic water along the side of the vial. Never spray directly onto the powder. Let it dissolve naturally - don't shake.
Storage
Once reconstituted, store in the refrigerator (2-8°C). Most peptides remain stable for 4-6 weeks when properly stored.
Syringe Selection
U-100 syringes are most common. For very small doses, U-50 or U-30 syringes provide better precision with larger unit markings.
Measuring Accuracy
Adding more water makes measuring easier but increases injection volume. Less water = more concentrated = smaller injection.
How to reconstitute a peptide, step by step
Reconstitution means turning the freeze-dried (lyophilized) powder in your vial into a liquid you can measure and inject. The water you add does not change how much peptide you have - it only decides how concentrated each draw is. Here is the whole process:
- Gather your supplies: the peptide vial, a vial of bacteriostatic water, alcohol wipes, a reconstitution syringe (1-3 mL), and U-100 insulin syringes for dosing.
- Let everything reach room temperature and wipe both vial stoppers with an alcohol swab.
- Draw your bacteriostatic water. Decide your total volume (the calculator above turns a target dose into a clean unit number), then draw that much water into the reconstitution syringe.
- Add the water slowly down the inside wall of the vial - never spray it straight onto the powder. Aim the stream at the glass so it runs down gently.
- Let it dissolve on its own. Swirl gently if needed. Do not shake - peptides are fragile, and shaking can damage them and create foam.
- Check the solution. It should be clear and colorless. If it stays cloudy or has visible particles, discard it.
- Store it in the refrigerator (2-8 degrees C) and draw each dose with an insulin syringe.
Reconstitution reference chart
How the same vial behaves at different water volumes. The dose stays identical - only the injection size and the units on your syringe change.
| 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 for a U-100 insulin syringe (100 units = 1 mL). Confirm with the calculator above for your exact vial and dose.
The reconstitution math, explained
Two simple formulas run the whole thing:
- Concentration = peptide amount / water added. A 10 mg vial with 2 mL of water is 10 / 2 = 5 mg/mL.
- Injection volume = your dose / concentration. A 250 mcg (0.25 mg) dose at 5 mg/mL is 0.25 / 5 = 0.05 mL, which is 5 units on a U-100 syringe (since 1 mL = 100 units).
That is exactly what the calculator does above - the formulas are here so you can sanity-check the result yourself.
Common mistakes to avoid
- Shaking the vial. Swirl, never shake. Agitation can degrade the peptide and create foam that is hard to draw.
- Spraying water onto the powder. Aim the stream at the glass wall so it runs down gently.
- Using non-bacteriostatic water for a multi-use vial. Without the preservative, a vial you draw from for weeks can grow bacteria.
- Over-diluting. Too much water means a large, awkward injection volume; too little makes tiny doses hard to measure accurately.
- Injecting a cloudy solution. A properly reconstituted peptide is clear. Cloudiness or particles means discard.
Frequently asked questions
How much bacteriostatic water do I add to a 10 mg vial?
There is no single correct amount - the water only sets the concentration, not your dose. A common choice is 2 mL, making a 5 mg/mL solution, so a 250 mcg dose is 5 units on a U-100 insulin syringe. Add 1 mL instead and the vial becomes 10 mg/mL, halving every injection volume. Pick the volume that turns your target dose into an easy-to-measure number - the calculator above does this for you.
Can I use regular water or saline instead of bacteriostatic water?
Use bacteriostatic water for any vial you draw from more than once - the 0.9% benzyl alcohol stops bacterial growth over the weeks a vial is in use. Sterile water and saline have no preservative, so they suit only a single-use, same-day reconstitution. Tap or bottled water is never appropriate.
How long does a peptide last once reconstituted?
Once mixed, store it in the refrigerator at 2-8 degrees C. Most peptides stay stable for roughly 4-6 weeks refrigerated, though this varies by compound - some are more fragile. Keep it out of light and do not freeze a reconstituted solution unless that specific peptide is known to tolerate it.
Why are doses measured in units instead of mL?
Insulin syringes are marked in units, and on the standard U-100 syringe 100 units equals 1 mL. So units is just an easier way to read a very small volume: 5 units = 0.05 mL, 10 units = 0.10 mL, and so on. The calculator converts your dose straight to units so you do not have to.
Can I shake the vial to make it dissolve faster?
No. Swirl it gently or let it sit - shaking can damage the peptide chains and whips up foam that is hard to draw cleanly. A gentle swirl is all a properly added solvent needs.
What happens if I add too much or too little water?
Either way your total peptide is unchanged - only the concentration moves. More water means an easier-to-measure but larger injection volume; less water means a more concentrated, smaller injection that can be harder to dose precisely. Choose a volume that lands your dose on a clean unit mark.
How do I convert milligrams to micrograms?
1 mg equals 1,000 mcg. So a 250 mcg dose is 0.25 mg, and a 5 mg vial holds 5,000 mcg. Most peptide doses are written in mcg while vials are labeled in mg, which is why the conversion comes up constantly.
Do I need to refrigerate the vial before reconstituting it?
Freeze-dried (lyophilized) powder is stable at room temperature for short periods and during shipping, but for long-term storage keep it cold or frozen. Once reconstituted, it must always be refrigerated.
How do I know how many doses are in a vial?
Divide the vial size by your dose. A 10 mg vial dosed at 500 mcg (0.5 mg) gives 10 / 0.5 = 20 doses. The calculator shows this as doses per vial automatically.
The solution should be clear, right?
Yes. A correctly reconstituted peptide is clear and colorless. If it stays cloudy, has floating particles, or changes color, do not use it - discard the vial.
Educational information for research purposes only. The peptides referenced here are not approved for human use, and nothing on this page is medical advice. Always follow applicable laws and consult a qualified professional.