Methodology

What we plot

Y-axis is estimated remaining active milligrams. For esters, milligrams injected are multiplied by the parent-hormone fraction (100 mg testosterone enanthate is not 100 mg testosterone). GLP-1s use a fraction of 1. This is not ng/dL and not a blood test.

The curve for one dose

activeDose = doseMg × activeFraction

remaining(t) =
  0                          if t < t0
  activeDose × (t − t0)/Tmax if t0 ≤ t < t0 + Tmax
  activeDose × 0.5^((t − t0 − Tmax) / t½)  otherwise

Every later dose is the same function, shifted in time. The chart adds them together. That superposition is why long esters climb for weeks and why weekly semaglutide plateaus around 4–5 half-lives.

Stats

• Peak is the high point in the last dosing interval, including Tmax after the last dose.
• Trough is remaining at the last dose time — leftover from previous doses, before this one rises.
• Swing is (peak − trough) / peak.
• Steady state is estimated as 5 half-lives from the first dose.
• Washout is Tmax + 5 half-lives after the last dose (~3% of that last dose left).

What we are not modeling

• Two-compartment models, volume of distribution, or ng/dL conversion.
• Non-linear Cmax, SHBG, aromatization, or individual metabolism.
• Custom user-defined half-lives, day-of-week pin calendars, or ng/dL conversion.