Peptide & TRT dosing calculators
Three accurate, mobile-friendly calculators for peptides, reconstitution, and testosterone protocols.
Turn any peptide dose into exact syringe units. Works for BPC-157, TB-500, semaglutide, tirzepatide, and more.
Open calculatorPlan how much bacteriostatic water to add and see concentration, units per dose, and doses per vial.
Open calculatorConvert weekly testosterone cypionate or enanthate dose into per-shot volume and syringe units.
Open calculatorFrequently asked questions
General
Are these calculators free?
Yes. Every calculator on this page is free to use, with no sign-up required. They are built for research, harm reduction, and accurate dosing.
Which calculator should I use first?
Start with the Peptide Reconstitution Calculator if you are mixing a new vial. Then use the Peptide Dosage Calculator to plan each injection. For testosterone protocols, use the TRT Dosage Calculator.
Do the calculators work on mobile?
Yes. All calculators are responsive and work on iPhone, Android, and desktop browsers — no app install required.
Are the results medical advice?
No. These tools are for educational and research reference only. Always confirm dosing with a licensed clinician before injecting any peptide, hormone, or medication.
Peptide reconstitution
How much bacteriostatic water should I add to a 5 mg peptide vial?
Most users add 1 mL, 2 mL, or 3 mL of BAC water to a 5 mg vial. 2 mL is the common default: it makes each 10 unit mark on a U-100 insulin syringe equal 0.25 mg (250 mcg) — easy math for BPC-157, TB-500, and GHK-Cu.
How do I convert mg to insulin syringe units after reconstitution?
Units = (dose in mg ÷ total mg in vial) × total units of BAC water added. On a U-100 syringe, 1 mL = 100 units. The Peptide Reconstitution Calculator does this automatically and shows units per dose and doses per vial.
What is the difference between bacteriostatic water and sterile water?
Bacteriostatic water contains 0.9% benzyl alcohol, which prevents bacterial growth so you can pull multiple doses from the same vial for up to 28 days refrigerated. Sterile water has no preservative and should be used within one dose.
How long does a reconstituted peptide last?
Most reconstituted peptides are stable for 14–28 days refrigerated at 2–8°C when mixed with bacteriostatic water. Fragile peptides like BPC-157 and GHK-Cu are best used within 2–4 weeks. Never freeze after reconstitution.
Can I mix two peptides in the same syringe?
Some pairs (e.g. CJC-1295 + Ipamorelin) are commonly co-injected in one syringe when concentrations and pH are compatible. Never combine copper peptides (GHK-Cu) with other peptides — they oxidize. When unsure, inject separately.
Peptide dosage
How many units is 250 mcg of BPC-157 on a U-100 syringe?
If you reconstitute a 5 mg BPC-157 vial with 2 mL of BAC water, 250 mcg (0.25 mg) equals 10 units on a U-100 insulin syringe. Change the vial size or water volume in the calculator to see the exact units for your setup.
What is the typical dose for semaglutide or tirzepatide?
Semaglutide is commonly titrated 0.25 mg → 0.5 mg → 1.0 mg → 1.7 mg → 2.4 mg weekly. Tirzepatide typically titrates 2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg weekly. Use the Peptide Dosage Calculator to convert each step to syringe units.
What size insulin syringe should I use for peptides?
A 0.3 mL (30 unit) U-100 insulin syringe with a 29–31 gauge, 5/16 inch needle is standard for subcutaneous peptide injections. Larger 0.5 mL or 1 mL syringes are only needed for higher volume doses like TRT.
Should peptides be injected subcutaneously or intramuscularly?
Most research peptides (BPC-157, TB-500, GHK-Cu, GLP-1 agonists, growth-hormone secretagogues) are dosed subcutaneously into the abdominal fat. IM is only used when a specific protocol or your clinician calls for it.
TRT dosing
How do I convert weekly TRT dose to per-shot units?
Divide your weekly mg dose by the number of injections per week, then divide by testosterone concentration (usually 200 mg/mL). Multiply by 100 to get U-100 insulin syringe units. Example: 140 mg/week split twice = 70 mg per shot ÷ 200 mg/mL = 0.35 mL = 35 units.
Is testosterone cypionate 200 mg/mL the same as enanthate 250 mg/mL for dosing?
No — the concentration is different, so volume per mg differs. Always enter your ester's exact mg/mL into the TRT Dosage Calculator. Cypionate and enanthate have nearly identical half-lives (~7–8 days) but slightly different peaks.
How often should I inject TRT?
Common protocols split the weekly dose into 2 injections (every 3.5 days), or into daily/EOD subcutaneous shots for smoother blood levels and lower estradiol conversion. The calculator supports any injection frequency.
Can I inject testosterone subcutaneously instead of intramuscularly?
Yes. Subcutaneous TRT with an insulin syringe (29–31 gauge, 5/16 inch) is well supported by peer-reviewed studies, produces stable levels, and is less painful. Use the same weekly mg dose — only the injection site changes.
Peptide dosage glossary
Quick definitions for the terms used across peptide reconstitution, syringe unit conversion, and TRT dosing.
- Reconstitution
- Dissolving a lyophilized (freeze-dried) peptide with bacteriostatic water to make an injectable solution.
- Bacteriostatic water (BAC water)
- Sterile water with 0.9% benzyl alcohol that inhibits bacterial growth, extending a mixed vial's usable life to ~28 days refrigerated.
- Concentration (mg/mL)
- Peptide milligrams divided by BAC water milliliters. Drives how many syringe units equal your target dose.
- U-100 insulin syringe
- Holds 100 units per 1 mL. 1 unit = 0.01 mL. The standard syringe for peptide and TRT subcutaneous dosing.
- U-40 insulin syringe
- Holds 40 units per 1 mL. 1 unit = 0.025 mL. Less common; using it in place of U-100 changes dose by ~60%.
- Subcutaneous (SC)
- Injection into the fatty layer under the skin (abdomen, flank, thigh) using a 29–31 gauge, 8 mm insulin needle.
- Intramuscular (IM)
- Injection into muscle tissue (glute, delt, quad) with a 23–25 gauge, 1 inch needle. Common for TRT esters.
- Half-life
- Time for blood levels to fall by half. Drives injection frequency — short half-life = more frequent shots.
- Ester
- Chemical tail attached to testosterone (cypionate, enanthate, propionate) that controls release speed and half-life.
- mcg vs mg
- 1 mg = 1,000 mcg. Peptide doses are often written in mcg; always confirm units before drawing.
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