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Half-Life Visualizer

Every dose decays on its own and the amounts add. That is the whole model, and it is why a compound with a one-week half-life dosed weekly settles at about twice a single dose while a two-hour compound dosed daily never accumulates at all. The compound list holds only those whose half-life comes from a source Prof. Peptide has read.

Last reviewed: September 21, 2026

A half-life and a schedule give a curve. Each dose decays on its own and the amounts add, which is what makes a compound accumulate or not.

Only compounds whose half-life Prof. Peptide can cite appear here. Half-life ~1 week. Source: FDA prescribing information (Wegovy / Ozempic).

How the model works

  • Each dose decays independently from the moment it’s given, and the amounts from every dose still in the body add together.
  • Half-lives per interval = hours between doses ÷ half-life. Four or more, and a dose has essentially cleared before the next; fewer than four, and some accumulates.
  • Accumulation ratio = 1 ÷ (1 − 0.5interval/half-life), the steady-state peak divided by the peak after a single dose.

This is a single-compartment model. It assumes a dose is fully present the instant it’s given and then decays at a constant rate. It ignores absorption — a real curve rises to a peak over hours rather than jumping — distribution into tissue, any change in clearance with dose, and every difference between one person and another. It is the arithmetic of a half-life and a schedule, not a prediction about a body.

Accumulation across the sourced compounds

Each compound below modelled at an illustrative interval — not a recommended schedule — and a dose of 1 unit, to show how differing half-lives change the outcome for the identical arithmetic:

CompoundHalf-lifeInterval modelledHalf-lives/intervalAccumulation ratio
Semaglutide168 h (~1 week)168 h1.000×2.000
Retatrutide144 h (~6 days)168 h1.167×1.803
Tirzepatide120 h (~5 days)168 h1.400×1.610
Ipamorelin2 h12 h6.000×1.016
PT-1412.7 h48 h17.778×1.000
Follistatin1.5 h24 h16.000×1.000

The pattern: a half-life close to the interval produces meaningful accumulation (semaglutide, weekly, roughly doubles); a half-life much shorter than the interval produces almost none (follistatin and PT-141, at the intervals shown, essentially reset between doses). Enter any of these compound-and-interval pairs into the calculator above and it returns the same ratios.

FAQ

half life visualizer accumulation calculator
This page models how a compound accumulates from a half-life and a dosing schedule you enter — a dose amount, the hours between doses, and a span of hours to chart. It only offers compounds whose half-life Prof. Peptide can cite to a source; a compound with no sourced figure cannot be modelled here.
What does half-lives per interval mean?
How many half-lives pass between one dose and the next. At four or more, each dose has essentially cleared before the next lands, so nothing meaningfully accumulates. Below four, some of each dose is still present when the next arrives, and the compound builds up toward a higher steady-state level.
How long until a compound reaches steady state?
About five half-lives, which the model reports as roughly 97% of the way to steady state. A compound with a one-week half-life takes about five weeks; one with a two-hour half-life takes about ten hours.
What does this model NOT account for?
Absorption (the model assumes a dose is fully present the instant it's given, rather than rising to a peak over hours), distribution into tissue, any change in clearance with dose size, and every difference between one person and another — age, kidney or liver function, body composition. It is the arithmetic of a half-life and a schedule, not a prediction about a specific body.

For every sourced and unsourced half-life Prof. Peptide tracks — not only the six modelled here — see the peptide half-life chart.