Reconstitution calculator
Calculate concentration, the volume to draw and the number of doses per vial for your lyophilized research peptides. Pick your insulin syringe and see the fill on a live 2D render.
Select a peptide to pre-fill the reconstitution parameters.
Calculation result
Draw the syringe to
40
units
Volume
0.4
mL
Concentration
5
mg/mL
Draws / vial
5
Level on a graduated syringe 1 mL (100 U)
This vial lasts 5 weeks
Syringe size
Target dose
the amount of peptide targeted
2 mg
2 mg = 2,000 mcg (µg)
Vial dosage
total peptide mass, in mg
10 mg
Bacteriostatic water
reconstitution volume, in mL
2 mL
Reta-R3 — Research protocol
Triple GLP-1/GIP/Glucagon agonist
- Dose (study protocol)
- 2 → 4 → 8 → 12 mg (escalation every 4 weeks)
- Frequency
- 1×/week (s.c.)
- Duration (published studies)
- 48 weeks (published trials)
Source : Jastreboff et al., NEJM 2023 (Phase 2, n=338)
Weight dose-response at 48 weeks: 2 mg (-7.2%), 4 mg (-12.9%), 8 mg (-17.2%), 12 mg (-24.2%).
This data comes from published studies compiled for informational purposes for laboratory professionals. No dose is recommended. Not intended for human consumption or animal use.
Read the full analysis Reta-R3Get your complete protocol
Personalised numeric summary + a printable step-by-step reconstitution procedure. We email it to you as a PDF.
How It Works
1. Concentration
Divide vial amount (mcg) by water volume (mL) to get concentration (mcg/mL).
2. Volume needed
Divide desired dose by concentration to get injection volume in mL.
3. Syringe units
Multiply mL × 100 to get U-100 syringe units (IU).
Example
- 5 mg vial + 2 mL water = 2.5 mg/mL
- Want 250 mcg (0.25 mg)?
- 0.25 ÷ 2.5 = 0.1 mL
- 0.1 mL = 10 units on a U-100 syringe
Research Use Only
This calculator is for research purposes only. Not medical advice.
Common Conversions
- 1 mg
- 1,000 mcg
- 500 mcg
- 0.5 mg
- 250 mcg
- 0.25 mg
- 100 mcg
- 0.1 mg
Syringe Units
- 0.3 mL syringe
- 30 units
- 0.5 mL syringe
- 50 units
- 1.0 mL syringe
- 100 units
Volumetric conversion tool for laboratory handling. Not any human or animal administration advice. Research use only.
How to use our peptide dosage calculator?
The calculation relies on a simple formula; the tool applies it automatically.
Calculating a peptide dose means dividing the amount you want by the concentration of the solution, then converting the result into syringe units. Pick a peptide, the amount in the vial and the volume of bacteriostatic water added — the calculator does the rest.
The base formula
Syringe units = (Dose in mg ÷ Concentration in mg/mL) × 100
Example: a 10 mg vial reconstituted with 2 mL of water gives a concentration of 5 mg/mL. To draw 2 mg: (2 ÷ 5) × 100 = 40 units on a U-100 syringe.
Which syringe should you choose?
U-100 syringes are the standard in peptide research — three main sizes:
- 0.3 mL — 30 unitsideal for micro-volumes (BPC-157, Selank, Semax). Fine graduation, precise reading.
- 0.5 mL — 50 unitsversatile for most peptides. A good precision / volume trade-off.
- 1.0 mL — 100 unitsneeded for larger volumes (Reta-R3, MOTS-c, NAD+). Maximum volume in a single draw.
Rule of thumb: always choose the smallest syringe that can hold your volume. The smaller the syringe, the wider the graduations and the easier the reading.
Reconstitution: how much water to add?
The bacteriostatic water volume sets the concentration. The more you add, the more dilute the solution and the larger the volume to draw.
10 mg + 2 mL
5 mg/mL
standard (Reta-R3, BPC-157, TB-500)
10 mg + 1 mL
10 mg/mL
high concentration, small draw volume
5 mg + 1 mL
5 mg/mL
5 mg vials (Selank, Ipamorelin)
Each peptide has reference concentrations drawn from the scientific literature. Select a peptide at the top of the page to pre-fill these parameters automatically — for information only, laboratory research use.
Three parameters, a precise calculation
Enter three values, the calculator does the rest.
Your target dose
The amount of peptide per draw, in milligrams or micrograms.
The vial dosage
The total mass of lyophilised peptide stated on the label (5 mg, 10 mg…).
The BAC water volume
The bacteriostatic water added for reconstitution. It determines the final concentration.
Calculation formulas
All the formulas used, with a worked example to check your results.
Show the formulas and a worked example
Concentration (mg/mL) = Vial dosage (mg) ÷ Water volume (mL)
Volume to draw (mL) = Target dose (mg) ÷ Concentration (mg/mL)
Syringe units (U-100) = Volume to draw (mL) × 100
Doses per vial = Vial dosage (mg) ÷ Dose per draw (mg)
Vial duration = Doses per vial ÷ draw frequency
Example : a BPC-157 10 mg vial reconstituted with 2 mL of water → concentration of 5 mg/mL. For a target dose of 250 mcg (0.25 mg), draw 0.05 mL, i.e. 5 units on a U-100 syringe. The vial delivers 40 draws; at one draw per day, it lasts 40 days.
What you need, nothing else
The essentials for a clean laboratory reconstitution.
Bacteriostatic water
10 ml · 0.9% benzyl alcohol
Keeps ~28 days after opening. Available from a pharmacy or in our catalogue.
Drawing syringe (optional)
3 ml · 21G × 40 mm needle
To draw the bacteriostatic water in one go. From a pharmacy (~€3-5) or replaceable by several draws with the graduated syringe.
U-100 graduated syringe
1 ml (100 units) · 29G × 8 mm
Unit graduation to precisely measure the calculated volume. Available as a pack in our catalogue.
70% alcohol + gauze
Sterile swabs
Disinfection of the stoppers before each draw.
Step-by-step protocol
Follow the order: each step sets up the next.
Prepare your equipment
On a clean surface: lyophilised vial, bacteriostatic water, U-100 graduated syringe, 70% alcohol, sterile gauze. Optional: 3 ml drawing syringe.
⚠️ Wash your hands and disinfect the surface with alcohol.
Take the vial out of the fridge
Let it return to room temperature for 15-20 min. A cold peptide + cold water increases the risk of aggregation. Inspect: uniform white powder, no discoloration.
Disinfect the stoppers
Wipe the rubber stopper of both the peptide vial AND the water vial with alcohol. Let dry for 10 seconds.
Draw the bacteriostatic water
With the syringe, draw the volume calculated by the calculator. E.g. a 10 mg vial reconstituted to 2 mL.
⚠️ Use ONLY sterile bacteriostatic water (no distilled water, no saline).
Inject the water slowly into the vial
Tilt the vial at 45°. Aim the stream at the inner wall of the vial, never directly at the powder. Drop by drop, 10-15 seconds minimum.
⚠️ Never spray the water directly onto the powder — risk of denaturation.
Dissolve gently
Stand the vial upright. Roll it gently between your palms for ~30 seconds. Let it rest 2 min. The solution must be perfectly clear.
⚠️ Never shake the vial: agitation denatures the peptide bonds.
Label and store
Write the reconstitution date on the vial (permanent marker). Store at 2-8 °C, upright. Indicative duration ~28 days depending on the compound.
⚠️ Do not freeze. Once reconstituted, the peptide loses stability at room temperature after 24 h.
Draw the calculated volume
For each draw: disinfect the stopper, draw the volume in units (U-100) shown by the calculator, then purge the bubbles.
Peptide storage conditions
Before and after reconstitution.
Before reconstitution (lyophilised)
Away from light, in the refrigerator (2-8 °C). The lyophilised form is stable over a long period depending on the compound.
After reconstitution
In the refrigerator (2-8 °C), to be used within a limited time (a few weeks depending on the compound).
To avoid
Repeated freeze/thaw cycles, heat, direct light and vigorous shaking, which degrade the peptide.
FAQ — reconstitution & dosage
The questions we get asked most.
Which water should I use for reconstitution?
How much water should I add?
How do I read the result in “units”?
Is the calculator usage advice?
How long does the solution keep?
Can I refreeze after reconstitution?
PEPTIDESunderstanding before use
The clear, source-backed guide to understanding how they work, their uses, their benefits, their risks and the essential precautions — before you get started.
- How peptides really work
- Their uses and what the research says
- Reported benefits vs marketing promises
- Risks, limits and essential precautions
Research peptides — Research Use Only
- Not for human consumption
- Not for the diagnosis, treatment or prevention of any disease