TRT Dose-Response Estimator
Model peak, trough, and average testosterone levels for a weekly dose and ester.
Splitting the same weekly total smooths the peak-to-trough swing.
Half-life 7 days · typical range 100–600 mg.
Modeled estimate — not a prediction.
Real serum levels vary with individual clearance, injection depth, site, and assay method. Two people on the same dose can land hundreds of ng/dL apart. Confirm any dosing decision with bloodwork drawn at the trough, interpreted by a clinician.
Modeled steady-state levels
Peak (Cmax)
above rangeTrough (pre-dose nadir)
within rangeAverage over interval
above rangeReference band: 300–1000 ng/dL (Eugonadal total T). Stats are read from the last full injection interval of a 12-week protocol (13 injections modeled).
Modeled concentration curve
| Date | ng/dL |
|---|---|
| Aug 17 | 0 |
| Aug 23 | 427 |
| Aug 30 | 648 |
| Sep 6 | 764 |
| Sep 13 | 826 |
| Sep 20 | 861 |
| Sep 27 | 881 |
| Oct 4 | 894 |
| Oct 11 | 903 |
| Oct 18 | 911 |
| Oct 25 | 917 |
| Nov 1 | 923 |
| Nov 8 | 929 |
Green band = eugonadal reference range (300–1000 ng/dL). Curve is a linear PK model of the reported schedule.
Educational use only — not medical advice. This is a modeled estimate from a linear pharmacokinetic model (Bateman superposition), not a prediction of your bloodwork. Individual clearance, ester purity, injection technique, body composition, SHBG, and assay variability all shift real levels — sometimes substantially. Never start, stop, or adjust TRT based on this tool; confirm with trough bloodwork and a clinician.
About this tool
The TRT Dose-Response Estimator models where serum testosterone is likely to sit on a given protocol. Pick an ester — enanthate, cypionate, propionate, undecanoate (castor or MCT oil), or suspension — enter your weekly dose and duration, and the tool runs the same pharmacokinetic model as the plotter to estimate steady-state peak, trough, and average levels in ng/dL, drawn against the eugonadal reference band of 300–1000 ng/dL. Compare once-weekly against twice-weekly to see how much the peak-to-trough swing narrows. Every number is a modeled estimate, not a prediction — real levels vary with individual clearance, so confirm with bloodwork before changing anything.
How to use it
- 1 Select your testosterone ester — the dose field pre-fills with that ester's typical default.
- 2 Enter your total weekly dose in mg and how many weeks you've been on the protocol (steady state needs ~4–5 half-lives).
- 3 Choose 1×/week or 2×/week to see how splitting the same weekly total affects the peak-to-trough swing.
- 4 Read the modeled peak, trough, and average against the 300–1000 ng/dL band — then confirm with a trough blood draw rather than adjusting dose off the model.
Frequently asked questions
How accurate is this TRT dose estimator?
It's a modeled estimate from a linear pharmacokinetic model, not a prediction. Two people on the same dose can test hundreds of ng/dL apart because clearance, injection site, body composition, SHBG, and assay method all differ. Use it for direction and magnitude — never as a substitute for bloodwork.
What's the difference between injecting once vs twice per week?
The weekly total is the same, but splitting it raises the trough and lowers the peak, narrowing the swing. Many people report fewer side effects (estradiol spikes, mood swings) on the smoother curve; the tool shows the modeled difference directly.
When should I draw bloodwork on TRT?
Standard practice is a trough draw — immediately before the next scheduled injection — after the protocol reaches steady state (roughly 4–5 half-lives: ~5 weeks for enanthate/cypionate, much longer for undecanoate). The modeled trough estimates what that draw is targeting.
Educational use only — not medical advice. Results are estimates based on published formulas and models.