Free calculators for injectable protocols
Reconstitution, syringe units, half-lives and steady state — the arithmetic people do on the back of an envelope at the kitchen table, done properly. Free, no account, no email.
Why these exist
Every one of these calculators already runs inside the TherapyLog app, where it is part of the free tier. Putting them on their own pages is not a marketing exercise: the questions they answer — how much water goes in this vial, how many units is 2.5 mg, how long until this has cleared — get asked by people holding a vial right now, and the answers they find are usually a forum reply with no working shown.
So each page shows its working: the formula written out, and one worked example run through it with real numbers. And each calculator runs the same code the app runs rather than a re-implementation of it — the function source is copied out of the app when this page is built, and a check in continuous integration compares the two so they cannot drift apart. The comment above that function in the app says why it matters: a wrong number here ends up in a syringe.
The calculators
Peptide reconstitution calculator
Vial strength, bacteriostatic water and target dose in; the draw in units and ml out, with a syringe diagram. Also runs backwards — tell it the dose and the units you want to draw, and it solves for the water to add.
Insulin syringe unit converter
Units to ml and back on U-100 syringes, with the half-unit rule, the barrel sizes and a table of the conversions people look up over and over.
Testosterone dose calculator
A weekly testosterone dose split by injection frequency, in mg, ml and syringe units, with the modelled peak-to-trough swing for cypionate, enanthate and propionate at that cadence.
Free testosterone calculator
Calculated free and bioavailable testosterone from total T, SHBG and albumin by the Vermeulen equation, in whatever units your lab printed — and why the answer depends on the SHBG assay.
Half-life and steady-state calculator
Single-dose and repeated-dose curves from published half-lives, plus time to steady state, accumulation ratio and peak-to-trough ratio for the interval you pick.
Combined syringe planner
Plan a multi-compound draw and see the fill level, with the compatibility rules the app enforces: oil and water do not share a syringe, suspensions draw alone, fragile proteins are not blended.
Can you take these together?
Every interaction pair the app knows about, by severity, with what to watch. Not exhaustive and not a safety clearance.
Per-compound pages
Reconstitution, pre-filled: the same calculator started at that compound's typical vial sizes, with a milligram-to-units table, the modelled half-life and the storage rule — Semaglutide, Tirzepatide, Retatrutide, BPC-157, TB-500.
Half-life and steady state: one page per compound with published pharmacokinetic data, each with the curve pre-drawn, the numbers, where they come from, and the monitoring panel the app records — Semaglutide, Tirzepatide, Retatrutide, Testosterone Cypionate, Testosterone Enanthate, BPC-157, TB-500, CJC-1295, Ipamorelin, Tesamorelin, HCG, Enclomiphene, Anastrozole, Sermorelin, MK-677 / Ibutamoren.
Pre-mixed blends
A blend vial dissolves several peptides in the same water, so a draw takes all of them in whatever ratio the vial was compounded at — you cannot dose one without dosing the others. These pages work out what a single draw actually delivers of each, and compare it against what the literature and community practice describe for each compound on its own. The gap is usually larger than people expect: BPC-157 and TB-500 blend, GLOW blend, KLOW blend.
What a calculator can and cannot tell you
Serum-level curves are modelled from published half-lives and time-to-peak values, not measured in you. Where the published data is thin, the page says the half-life is an estimate rather than presenting it as fact. And none of these pages decides a dose: they make the arithmetic reliable, which is a different job.
Reading your bloodwork instead
If what you actually want is help reading a lab report — what the number means, which assay produced it, and why two labs can disagree about the same blood — that is what the lab-marker pages are for. And if you want the compound itself — what it is, what the app records about it and what it is monitored with — that is the compound reference.
The app is where these calculators live alongside the log they feed: doses, vials, bloodwork and the curve for everything you have entered.
Open the appThis calculator does the arithmetic you typed and nothing else. It does not know what is actually in your vial, whether the label is accurate, or anything about you. Confirm the vial strength and the diluent volume on your own label before you draw, and take dosing decisions to a qualified provider.