How to Calculate Peptide Dosage?

If you are new to laboratory dilution, calculating how to measure peptides can feel complex, but the math follows three simple, sequential steps: (1) Find your solution concentration by dividing total vial milligrams by diluent milliliters (e.g. 5 mg ÷ 2.0 mL = 2.5 mg/mL); (2) Determine the liquid volume required for your target amount by dividing dose milligrams by concentration (e.g. 0.25 mg ÷ 2.5 mg/mL = 0.10 mL); and (3) Convert milliliters to syringe units by multiplying by 100 on a standard U-100 insulin syringe (0.10 mL × 100 = 10 units). This basic walk-through explains peptide arithmetic for beginners with complete transparency.

When lyophilized peptide powders are synthesized, the active peptide molecule is typically bound to a counter-ion salt (such as acetate or trifluoroacetate) and retains residual moisture. As a result, a 10 mg vial of gross lyophilized powder may contain 8.0 mg to 8.5 mg of pure peptide base (an 80% to 85% net peptide content). For advanced protocols requiring salt-form purity arithmetic, review our detailed guide on net peptide content and laboratory adjustment formulas on the KPV dosage calculator. For standard preparations where the label designates net active mass, standard volumetric formulas apply directly.

Understanding vial yield allows researchers to calculate cost per dose using basic arithmetic: Cost per dose ($) = Total vial price ($) ÷ Doses per vial. Total doses per vial is computed as Total vial mass (mg) ÷ Desired dose (mg). For example, if an illustrative research vial costs $50 and contains 5.0 mg of compound, an illustrative 250 mcg (0.25 mg) dose yields 5.0 mg ÷ 0.25 mg = 20 doses. Dividing the vial price by the yield produces $50 ÷ 20 = $2.50 per dose. Please note: FreePeptideCalculator.com is an independent, 100% free web utility with no fees, subscriptions, or paywalls. This site does not sell peptides, endorse commercial vendors, or track dynamic market prices.

For other lyophilized compounds (such as NAD+, glutathione, L-carnitine, or novel research peptides without dedicated calculator pages), the reconstitution math is identical. Physical concentration in liquid solution is governed strictly by active mass (mg) and diluent volume (mL), meaning the three-step formulas on this page apply universally.

This website provides deterministic arithmetic only; it never prescribes, recommends, or establishes clinical dosage amounts. In legitimate medical care, your starting dose comes exclusively from a licensed prescriber, an FDA-approved drug label, or an Institutional Review Board (IRB)-approved clinical trial protocol. For an analysis of why subcutaneous injection volumes have physical limits, see our guide on how much peptide should you inject. Before preparing any medication, verify your parameters using this pharmacist checklist: (1) Written drug name and salt form; (2) Prescribed amount in exact milligrams (mg) or micrograms (mcg); (3) Reconstituted vial concentration in mg/mL; (4) Syringe type (must explicitly specify U-100); (5) Calculated draw stated in both syringe units and milliliters (read back and confirmed with your pharmacist).

If you prefer a specific calibration (such as 25 mcg per syringe graduation unit), calculate the required diluent volume before reconstitution. Formula: Diluent Volume (mL) = [Vial Mass (mg) × 1,000 mcg/mg] ÷ [Desired mcg per unit × 100 units/mL]. For a 10 mg vial targeting 25 mcg per unit: 10,000 mcg ÷ (25 × 100) = 10,000 ÷ 2,500 = 4.0 mL. Adding 4.0 mL of bacteriostatic water creates 2.5 mg/mL, making each U-100 tick mark equal exactly 25 mcg.