InjectBuddy is a free suite of browser-based dosing tools for injectable hormone therapy and peptide protocols. Work out your exact injection volume and insulin-syringe units for testosterone replacement therapy (TRT), GLP-1 medications such as semaglutide and tirzepatide, HCG, and research peptides like BPC-157 and TB-500 — plus reconstitution maths, BMI, and the free testosterone index.
Every calculation runs locally in your browser: no login, no account, and no personal health data is ever stored or sent to a server. Each tool converts your prescribed dose and vial concentration into a clear draw volume and the matching mark on a U-100 syringe, so the number on the label and the line on the barrel finally line up. InjectBuddy performs arithmetic only and is not medical advice — always confirm your dose and protocol with your prescribing doctor, nurse, or pharmacist. The two most-used tools are the Testosterone (TRT) dosage calculator and the peptide dosage calculator — start there if you inject testosterone or reconstitute peptide vials.
New to injections or dialling in a protocol? Our free injection and dosage guides explain the maths, titration, storage, and safety in plain language — each one links back to the matching calculator.