Steroid cycle and TRT plotter

testosterone: exogenous contribution in serum (ng/dL).

The body's own testosterone is excluded. This is the contribution from entered doses, not the total blood level.

Fixed reference profile: Population PK model derived from 31 healthy adult men; the display uses its typical fixed parameters rather than individual fitted parameters. Testosterone cypionate depot injection studied in the repeated-dose cohort analyzed by Bi et al.; Intramuscular. Fixed reference weight: 85 kg.

Changing dose or schedule explores a scenario; it does not personalize the reference profile or establish a studied regimen.

Input dose basis: Nominal testosterone cypionate mg

Source exposure scope: The source cohort received 14 weekly injections in 100, 250 or 500 mg groups. Other scenarios are linear-model simulations, not additional observed regimens or recommendations.

Adult IM testosterone cypionate: injected-drug model component

bi-2018-cypionate-im-component · version 1

• Fixed reference covariates: baseline weight 85 kg, albumin 4.60 g/dL, weight change +2.90 kg and albumin change −0.20 g/dL; all covariate multipliers equal one.
• Zero individual random effects, zero initial exogenous amount and zero endogenous input for the isolated injected-drug component.
• Nominal testosterone cypionate mg enter the depot as in the authors’ code; apparent clearance and volume already reflect this convention. No extra 0.70 ester factor is applied.

Model structure

One compartment with absorption

Apparent clearance (CL/F)

108.5063 L/hour

Apparent central volume (Vc/F)

14449.6 L

Absorption rate (ka)

0.05088958 /hour

Input mass conversion

1 mg modelled mass per mg entered

• This mathematical component excludes endogenous testosterone. It is not a measured blood fraction and cannot be compared directly with a total-testosterone test or laboratory range.
• The original total-testosterone analysis used time-varying LH and covariates. The display does not reconstruct those inputs or predict hormone recovery or fertility.
• The reference population was healthy adult men, not a personalized hypogonadism model; other formulations, routes and populations may differ.
• Reproducing the published component is a numerical/source check, not new clinical validation or a dose-selection method.

• Bi et al. 2018 — population PK/PD model

  Supplementary Model Files, PK Model for Total Testosterone: CL/F 2.60415 kL/day, V/F 14.4496 kL, Ka 1.22135/day. This display isolates the linear injected-dose contribution and omits endogenous input.