Pharmacokinetic concentration simulator for semaglutide, tirzepatide, and retatrutide. Visualize how drug levels build up, explore titration schedules, and simulate missed doses.
Select Medication
GLP-1 receptor agonist. Weekly subcutaneous injection. 7-day half-life provides stable plasma levels.
Brand names: Wegovy, Ozempic
Simulation Duration
Relative concentration (% of peak). Click any week bar to simulate a missed dose.
7d
Half-life
168h
~5 wks
Steady State
4–5 half-lives
~73h
Peak Time
after injection
68%
Trough Level
of peak at steady state
Click any week to simulate a missed injection. The curve above updates in real time.
At 1.7mg — from FDA prescribing information and clinical trial data
One-Compartment PK Model
Concentration curves use a standard one-compartment pharmacokinetic model with first-order absorption (Bateman function) and elimination. Each weekly injection superimposes on active doses to show how drug levels accumulate toward steady state.
Titration Schedules
GLP-1 medications use gradual dose escalation to minimize GI side effects. The timeline follows standard prescribing information. Each step typically lasts 4 weeks before increasing to the next dose level.
Side Effect Rates
Percentages are from FDA prescribing information and published clinical trial data. Rates generally increase at higher doses, which is why gradual titration is recommended. Individual experiences vary significantly.
How accurate is the concentration curve?
The curves are based on a one-compartment PK model using published parameters from FDA prescribing information and clinical trial data. They show relative concentration patterns — not absolute blood levels — and illustrate general pharmacokinetic principles. Individual responses vary based on body weight, injection site, and metabolism.
What happens if I miss a dose of semaglutide or tirzepatide?
For semaglutide (7-day half-life), levels decrease roughly 50% over a missed week. It typically takes 2–3 subsequent doses to return to previous steady-state levels. General guideline: if less than 5 days late, take the missed dose. If more than 5 days late, skip it and resume on your regular schedule.
How long does it take for semaglutide to reach steady state?
Semaglutide reaches approximately 90% of steady-state concentration after 4–5 half-lives — roughly 4–5 weeks of consistent weekly dosing. The plotter visualizes this buildup over your selected duration.
What is retatrutide and why is it marked investigational?
Retatrutide (LY3437943) is a triple agonist targeting GLP-1, GIP, and glucagon receptors. It is currently in Phase 3 clinical trials and has not received FDA approval. Phase 2 data showed up to 24.2% body weight reduction at 48 weeks.
Ready to source GLP-1 peptides?
Purgo Labs offers pharmaceutical-grade semaglutide, tirzepatide, and retatrutide with third-party COA testing.
This tool is for educational purposes only. Concentration curves show relative patterns based on published pharmacokinetic parameters and do not represent actual blood levels in any individual. Dosing decisions should always be made with a qualified healthcare provider. Compound Review does not provide medical advice, diagnosis, or treatment recommendations.
Medical Disclaimer: All content on this site is for educational and research purposes only. Research peptides are not FDA-approved for human use. Always consult a qualified healthcare professional before considering any peptide or supplement protocol. Nothing on this site constitutes medical advice, diagnosis, or treatment.