Semaglutide Dosing Simulator
See semaglutide's concentration curve over a weekly schedule — the rise to steady state, the saw-tooth between doses, the dip when you miss one, and the wash-out after your last shot. Built on the published ~7-day (165-hour) elimination half-life.
Model Your Schedule
Pick a dose, an interval, and how long you want to model. The chart plots relative concentration (% of a single dose's peak) using a single-compartment, first-order elimination model. This shows the shape of a schedule you enter — it is not an absolute blood level and never a dose recommendation.
Single-compartment, first-order elimination (C(t)=Σ dose·e^(−k·t), k=ln2/7d), superposed across doses. Relative concentration only — no volume-of-distribution is assumed, so the curve shows shape and timing, not mg/mL. Absorption (semaglutide peaks 1–3 days post-injection) is simplified to an instantaneous input. Educational purposes only — not medical advice.
How Semaglutide Behaves In The Body
Semaglutide's elimination half-life is approximately 1 week (~165 hours), per the FDA Ozempic label. Albumin binding and resistance to degradation are what stretch it — that long half-life is exactly what permits once-weekly dosing.
Because each weekly interval equals one half-life, the drug accumulates to roughly 2× a single dose, and steady state is reached after about 4–5 doses (4–5 half-lives). Set duration to 12 weeks and watch the curve flatten into its repeating peak/trough band.
With a week-long half-life, one missed weekly dose is a slow sag, not a cliff — concentration roughly halves over the skipped week. The Ozempic label says take a missed dose within 5 days; past that, skip it and resume schedule. Toggle the missed-dose box to see it.
After the last dose, levels fall below ~10% of peak by about 23 days (3–4 weeks) and below 1% by ~6–7 weeks. That slow tail is why appetite suppression fades gradually and why it lingers in your system for over a month.
Key Takeaways
- Semaglutide's half-life is ~1 week (~165 h) — published in the FDA Ozempic label
- Weekly dosing reaches steady state in ~4–5 weeks and accumulates to ~2× a single dose
- A missed weekly dose causes a gradual ~50% dip, not a sudden drop
- After the last dose it takes ~3–4 weeks to fall below 10% and ~6–7 weeks below 1%
- The math (one-compartment first-order elimination) is standard, well-defined pharmacokinetics
- This is relative concentration — it does not predict your actual mg/mL blood level
- Absorption is simplified; real semaglutide peaks 1–3 days after injection, not instantly
- Individual clearance varies with body weight, renal function, and formulation
- It models the schedule you enter — it does not suggest a dose or a titration plan
- Half-life data exists for semaglutide; most research peptides have no citable human PK and are excluded
Frequently Asked Questions
What is the half-life of semaglutide?
Semaglutide has an elimination half-life of approximately 1 week (about 165 hours, ~7 days), per the FDA Ozempic prescribing information. That long half-life is what allows once-weekly subcutaneous dosing. This simulator uses 7 days as the half-life input.
How long does semaglutide take to reach steady state?
With once-weekly dosing, steady state is reached after about 4 to 5 weeks (~4–5 half-lives). Because the weekly interval equals one half-life, the trough sits at about half the peak and concentration accumulates to roughly twice a single dose at steady state.
What happens if I miss a dose of semaglutide?
Because the half-life is about a week, a single missed weekly dose causes a gradual dip rather than a sudden drop — concentration falls by roughly half over the 7 days before the next dose. Toggle the missed-dose box in the simulator to see the dip and recovery. The Ozempic label advises taking a missed dose within 5 days; if more than 5 days have passed, skip it and resume your regular schedule.
How long does semaglutide stay in your system after the last dose?
With a ~7-day half-life, concentration falls below about 10% of peak roughly 23 days (3–4 weeks) after the last dose, and below 1% by about 6–7 weeks. This is why it can take over a month to clear and why appetite effects fade gradually rather than immediately.
Why only semaglutide — where are the other peptides?
A pharmacokinetic curve is only as honest as its half-life input. Semaglutide has a published, regulator-documented human half-life. Many research peptides (BPC-157, TB-500, and most experimental compounds) have poorly-characterized or unpublished human PK — modeling them would mean inventing numbers. We exclude what we can't cite rather than draw a confident but fabricated curve.
🛒 Injection & Storage Supplies
If you're modeling a real subcutaneous schedule, these are the supplies it implies. Affiliate links — they support HighPeptides at no extra cost to you.
Sourcing research peptide & bacteriostatic water? Swiss Chems carries research-grade kits and reconstitution supplies. For human therapy, use a licensed pharmacy and prescriber.
Educational purposes only. Not medical advice. This simulator is an illustrative pharmacokinetic teaching tool. It plots relative concentration from a published half-life; it does not output your actual blood levels, does not recommend a dose or schedule, and is not a personalized prediction.
Semaglutide is a prescription medication with a real side-effect profile. Peptides sold for research are labeled "not for human consumption." Always work with a qualified healthcare provider before starting, changing, or stopping any therapy.