Peptide reconstitution calculator
A peptide reconstitution calculator turns the vial size and the water you add into a concentration, then converts an amount into a volume and into U-100 insulin syringe units. For example, 5 mg mixed with 2 mL of water is 2,500 mcg per mL, so an example amount of 250 mcg is 0.1 mL, or 10 units. Free, instant, no signup required.
Illustrative example amounts only, not recommended doses
Concentration
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Equivalent volume (unit conversion)
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Units are marks on a U-100 insulin syringe, where 100 units = 1 mL.
Learn what these numbers mean
The calculator does the arithmetic. Foundations, our free course, covers what it leaves out: what a peptide is, how the research behind them works, and how to tell a real trial result from a forum claim.
How the reconstitution math works
A worked example of the conversions the calculator does. The numbers are arbitrary and chosen to keep the arithmetic easy. They are not recommended amounts.
- Start with a vial holding 5 mg of freeze-dried peptide, mixed with 2 mL of bacteriostatic water.
- Convert milligrams to micrograms. 1 mg is 1,000 mcg, so the vial holds 5 x 1,000 = 5,000 mcg.
- Find the concentration. 5,000 mcg divided by 2 mL is 2,500 mcg per mL (2.5 mg/mL).
- Convert an example amount to a volume. 250 mcg divided by 2,500 mcg per mL is 0.1 mL.
- Convert the volume to syringe units. A U-100 insulin syringe is marked 100 units per mL, so 0.1 mL x 100 = 10 units.
In one line: units = example amount (mcg) / (vial size (mg) x 1,000 / water (mL)) x 100.
The water changes the concentration, not the amount of peptide in the vial. Mix the same 5 mg vial with 1 mL instead and the concentration doubles to 5,000 mcg per mL, so the same 250 mcg takes half the volume: 0.05 mL, or 5 units.
Core reconstitution concepts
Understanding the science of peptide solubility and preparation. For the full walkthrough, read our step-by-step guide to reconstituting peptides.
Reconstitution is the process of dissolving a freeze-dried (lyophilized) peptide powder back into a liquid solution so it can be measured and studied. Most research peptides ship as a dry powder in a sealed vial and must be reconstituted before laboratory use.
Lyophilization (freeze-drying) is a preservation method where water is removed from a frozen peptide solution under vacuum. The result is a stable, dry powder that can be stored for months without degrading. This is why most research peptides arrive as a white or off-white powder or puck at the bottom of the vial.
Peptides degrade rapidly in liquid form: heat, light, and bacteria break them down. Shipping and storing them as a dry powder preserves their potency. Reconstitution converts them back into a measurable liquid solution for research purposes, ensuring minimal degradation prior to use.
Bacteriostatic water (BAC water) is sterile water that contains 0.9% benzyl alcohol as a preservative. The benzyl alcohol inhibits bacterial growth, which allows a reconstituted vial to be used multiple times in a laboratory setting over days or weeks without contamination. It is the standard solvent for peptide research.
Sterile water for injection can dissolve the peptide, but it lacks preservatives. Without the benzyl alcohol found in bacteriostatic water, bacteria can grow in the solution after the first puncture. If sterile water is used, research protocols generally require the entire vial to be used in one session. For multi-use research vials, bacteriostatic water is preferred.
Standard research protocols involve drawing bacteriostatic water into a syringe and introducing it slowly down the inside wall of the peptide vial to avoid direct impact on the powder. The solution is then swirled slowly until the powder fully dissolves. Researchers avoid shaking the vial, as this can denature the delicate peptide structure.
Frequently asked questions
There is no single required volume. More water results in a lower concentration and larger theoretical draw volumes. Less water results in a higher concentration and smaller volumes. Common research choices are 1-2 mL for most peptide vials. Use the conversion tool above to visualize how volume affects concentration.
On a standard U-100 insulin syringe, 100 units equals 1 mL. So 10 units = 0.1 mL, 5 units = 0.05 mL, and so on. This tool performs a neutral unit conversion. It expresses a target amount as an equivalent volume in theoretical syringe units based on the liquid concentration. It is a math illustration only, not a dosing recommendation.
Reconstituted peptides are typically stored refrigerated at 2-8 degrees C. Most remain stable for 2-4 weeks when mixed with bacteriostatic water. Research guidelines suggest keeping solutions away from light and avoiding freezing, which can damage the molecular structure.
No. The total amount of peptide in the vial remains constant. Adding more water simply changes the concentration (mg per mL). This mathematical tool handles these calculations to show the required draw volume for a target amount.
Divide the amount of peptide in the vial by the volume of water added, after converting milligrams to micrograms (1 mg = 1,000 mcg). A 5 mg vial mixed with 2 mL of water works out to 5,000 mcg divided by 2 mL, or 2,500 mcg per mL. The calculator above shows the result in both mg/mL and mcg/mL.
On a U-100 insulin syringe, multiply the volume in mL by 100, because 100 units equals 1 mL: 0.1 mL is 10 units and 0.25 mL is 25 units. The conversion only holds for U-100 syringes. A U-40 syringe is marked for 40 units per mL, so the same volume reads as a different number of units.
No. This calculator is an educational unit conversion tool for research purposes. It does not recommend dosages, protocols, or peptides for human use. Always consult a qualified healthcare professional regarding any medical concerns.