Peptide Calculator

What Is Peptide Reconstitution?

Lyophilized peptides are shipped as freeze-dried powder to preserve stability during transit and storage. Before use in a research context, the powder must be reconstituted by adding bacteriostatic water (BAC water) — a sterile water containing 0.9% benzyl alcohol as a preservative. The benzyl alcohol prevents microbial growth and extends the reconstituted peptide's usable life at refrigerator temperatures (2–8°C).

The volume of BAC water added directly determines the peptide concentration in solution. Adding more water decreases concentration (requiring a larger syringe draw per dose), while adding less water increases concentration (requiring a smaller draw).

How to Read Your Syringe

Standard insulin syringes are marked in units. A 1mL / 100-unit syringe means each unit equals 0.01 mL. If your calculation shows a draw of 25 units, pull the plunger back to the "25" mark on a 100-unit syringe. For a 50-unit syringe, the same 0.25 mL would read as 25 units on a 0–50 scale.

Always select the correct syringe type in the calculator to ensure the unit readout matches your actual syringe markings. Using the wrong syringe type is a common source of dosing error in research protocols.

Common Reconstitution Protocols

• GLP-1 peptides (Semaglutide, Tirzepatide, Retatrutide): Typically reconstituted in 2–3 mL BAC water. Higher water volume helps maintain low-concentration dosing required for research protocols mimicking clinical dose ranges.
• Short peptides (BPC-157, GHK-Cu, KPV): Usually reconstituted in 1–2 mL. These peptides are used at microgram doses, so higher concentration improves draw precision on standard insulin syringes.
• NAD+ (Buffered, 500mg): High vial strength requires larger water volumes. Common reconstitution is 5–10 mL depending on target concentration for IV or IM research protocols.

Storage After Reconstitution

Once reconstituted, peptide solutions should be stored at 2–8°C (standard refrigerator temperature) and protected from light. Most lyophilized peptides remain stable in solution for 4–6 weeks when stored properly with BAC water. Avoid repeated freeze-thaw cycles, which degrade peptide integrity.

For long-term storage, keep unreconstituted lyophilized powder at -20°C. Reconstitute only the portion needed for your active research period. Always refer to the product Certificate of Analysis (COA) for compound-specific stability data.