GLP-1 Medication Level Visualizer
GLP-1 medications are dosed weekly because they clear slowly, so each dose lands before the last has gone. This visualizer shows an illustrative curve of how the relative level builds toward steady state.
Presets set a typical half-life. Switch to custom to edit it.
How long it takes the level to fall by half. Editable.
A relative amount. The curve shows relative build-up, not a real blood concentration.
1 to 52 weeks of repeated weekly dosing.
Steady-state peak
2
Right after the last dose.
Steady-state trough
1.1
Just before the last dose.
How this works
The curve uses a single-compartment exponential decay. After one dose, the level falls by half every half-life. For repeated weekly dosing, the level at any time is the sum of every past dose, each decayed by how long ago it was given:
level(t) = sum over past doses of [ dose x exp( -ln(2) x (t - t_dose) / half-life ) ]
Because a new dose arrives before the previous one clears, the level accumulates week over week and then plateaus once intake and clearance balance. That plateau is steady state, and the gap between the weekly peak and trough is what the chart highlights.
The presets use published half-lives: semaglutide is roughly seven days and tirzepatide roughly five days, which is exactly why both are weekly injections. You can edit the half-life to explore other values.
This is an illustrative relative model, not a measured blood level. Real pharmacokinetics involve absorption, distribution, and individual variation this simple curve ignores. For the practical version of this idea, read how a GLP-1 dose plays out over a week.
Frequently asked questions
Is this my actual blood level?
No. It is an illustrative model of relative concentration built from a single half-life, not a measured or predicted blood level for you. Real pharmacokinetics involve absorption, distribution, and individual variation that this simple curve ignores.
Why does the curve keep rising for the first weeks?
With a long half-life, each weekly dose lands before the previous one has fully cleared, so the level accumulates. After several half-lives the build-up and the clearance balance out, which is steady state.
Where do the half-life numbers come from?
Semaglutide has a published half-life of roughly seven days and tirzepatide roughly five days, which is why both are dosed weekly. You can edit the half-life field to explore other values.
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