Peptide Dosing Calculator
Two tools in one: get a personalised starting dose estimate based on your body weight, age and sex — then instantly calculate the exact reconstitution and syringe volume for your vial.
Enter your body stats and research goal to get a personalised starting dose. Then click Use in Calc to automatically fill the reconstitution calculator.
Personalised Dose Estimator
Enter your stats to get a starting dose estimate
Research reference only — not medical advice. Weight-based estimates use published mcg/kg research ranges. Fixed-dose peptides show the same dose regardless of weight (as per clinical protocols). Body height does not affect peptide dosing. Always start at the conservative end and consult a qualified professional.
Enter your body weight above to get started.
How Peptide Dosing Calculations Work
Understanding the maths behind your dose prevents errors and improves reproducibility.
Step 1: Calculate Concentration
When you reconstitute a lyophilised peptide, you dissolve a known mass of powder into a known volume of bacteriostatic water. The resulting concentration determines how much liquid to draw per dose.
Example: 5,000 mcg ÷ 2ml = 2,500 mcg/ml
Step 2: Calculate Injection Volume
Once you know the concentration, divide your desired dose by the concentration to get the volume to draw.
Example: 500 mcg ÷ 2,500 mcg/ml = 0.2 ml
Step 3: Convert to Insulin Syringe Units
Standard insulin syringes are calibrated for 100 units = 1ml. Multiply your volume (ml) by 100 to get syringe units. This is the number you will draw to on the syringe barrel.
Example: 0.2 ml × 100 = 20 units
Choosing Your Reconstitution Volume
The amount of BAC water you use affects the precision of your dosing. Here are common scenarios:
| Vial | BAC Water | Concentration | 250mcg dose | 500mcg dose |
|---|---|---|---|---|
| 5mg | 1ml | 5,000 mcg/ml | 5 units | 10 units |
| 5mg | 2ml | 2,500 mcg/ml | 10 units | 20 units |
| 10mg | 2ml | 5,000 mcg/ml | 5 units | 10 units |
| 10mg | 5ml | 2,000 mcg/ml | 12.5 units | 25 units |
Tip: 2ml per 5mg vial (2,500 mcg/ml) is the most common reconstitution for BPC-157, TB-500, Ipamorelin and similar peptides. It gives 10–20 unit doses that are easy to measure accurately.
Frequently Asked Questions
Can I really base peptide dosing on body weight?
For some peptides yes — GHRP and GHRH peptides (Ipamorelin, CJC-1295, GHRP-2, Sermorelin) have established mcg/kg dosing conventions from research. HGH is dosed in IU/kg. BPC-157 and TB-500 doses are extrapolated from animal studies. GLP-1 peptides (Tirzepatide, Semaglutide) use fixed escalation protocols where body weight does not change the dose. The estimator clearly labels each approach.
Why does age affect the recommended dose?
Growth hormone declines significantly with age (roughly 14% per decade after 30). For GH-releasing peptides like Ipamorelin and GHRP-2, older researchers may need doses toward the higher end of the range to achieve comparable GH pulse amplitude. NAD+ also declines with age, justifying higher doses in older individuals.
How do I calculate peptide concentration?
Divide the total amount of peptide in the vial (in mcg or mg) by the volume of bacteriostatic water you added (in ml). For example, a 5mg vial with 2ml BAC water gives 2,500 mcg/ml.
How many units on an insulin syringe is my dose?
A standard insulin syringe has 100 units = 1ml. Divide your desired volume (ml) by 0.01 to get units. Example: 0.2ml = 20 units on a 100-unit syringe.
Should I use mg or mcg in my calculation?
Always use the same unit throughout. Most peptides are measured in mcg. GLP-1 peptides (semaglutide, tirzepatide) are measured in mg. 1mg = 1,000mcg. The calculator handles unit conversion automatically.
How much bacteriostatic water should I use?
The most common approach is 1–2ml per vial, giving a concentration that makes it easy to measure with an insulin syringe. Very small doses may require more BAC water (more dilute) to allow accurate measurement. Very high doses may require less.
What is bacteriostatic water and why is it used?
Bacteriostatic water (BAC water) contains 0.9% benzyl alcohol, which inhibits bacterial growth. This allows the reconstituted vial to be used multiple times over several weeks. Sterile water without benzyl alcohol is single-use only.
How long does a reconstituted peptide vial last?
Most reconstituted peptides stored at 2–8°C last 3–6 weeks. HGH should be used within 3 weeks. IGF-1 variants reconstituted in acetic acid last 2–3 weeks. Always inspect for cloudiness or particles before drawing — discard if present.