Key Takeaways
- Compound: Semaglutide (7.0-day half-life, GLP-1 receptor agonist)
- Protocol length: 12 weeks covering 2 dosing phases
- Steady state: Reached in approximately 5.0 weeks at each dose level
- Washout: Levels drop below 3% of peak in approximately 29 days after the last dose
- Elimination: The drug clears gradually based on its 7.0-day half-life, with levels halving roughly every 7.0 days
Semaglutide Washout: How Long Until Ozempic Leaves Your System
Quick Answer
Semaglutide has a half-life of 7.0 days. This scenario shows the elimination timeline after stopping Semaglutide. With a 7.0-day half-life, levels reach less than 3% of peak in approximately 29 days.
Data computed using GLP3Planner's pharmacokinetic model based on published clinical trial parameters.
Understanding the Washout Period
A washout period is the time it takes for a drug to leave your system after you stop taking it. For Semaglutide with its 7.0-day half-life, the drug does not disappear overnight. Instead, levels decrease by roughly half every 7.0 days.
This matters for several reasons. Side effects typically fade as levels drop, but they may linger for weeks after your last injection. If you are switching to a different medication, knowing when Semaglutide clears your system helps with timing. And if you are stopping altogether, understanding the washout timeline helps set realistic expectations for how long it takes before the drug's effects fully wear off.
The data below models the full elimination curve from steady state. It takes approximately 29 days for levels to drop below 3% of peak, which is generally considered the point where the drug is functionally cleared. The model uses GLP3Planner's published PK methodology.
Dosing Protocol
| Phase | Weeks | Dose | Frequency | Peak (mg) | Trough (mg) |
|---|---|---|---|---|---|
| Steady state at 2.4mg | 1-5 | 2.4mg | 1x/week | 4.65 | 2.57 |
| Stopped (washout) | 6-12 | 0mg | 1x/week | 0.04 | 0.02 |
Peak and trough values are modeled using a 7.0-day half-life from published clinical data. See methodology.
What the Numbers Mean
The table above shows modeled drug levels at each phase of this protocol. Here is what each column tells you:
Peak (mg)
The highest amount of Semaglutide in your body, measured right after an injection at steady state for that dose level. Higher peaks are associated with stronger appetite suppression but also more pronounced side effects, especially nausea.
Trough (mg)
The lowest amount remaining just before your next injection. This is the minimum drug level your body maintains between doses. The trough determines whether you still have therapeutic coverage throughout the dosing interval.
Steady State (~5.0 weeks)
The point where drug accumulation stabilizes. Before steady state, each dose adds more drug than your body eliminates, so levels keep climbing. Once reached, the amount in equals the amount out, and your peaks and troughs become consistent from week to week.
Washout (~29 days)
The time needed for levels to drop below 3% of peak after stopping. With a 7.0-day half-life, Semaglutide clears gradually. You will not feel the drug's full absence for several weeks.
These are population-average estimates based on clinical trial data. Individual levels vary based on body composition, metabolism, and injection site. For a personalized view, enter your actual doses into the Semaglutide calculator.
Pharmacokinetic Summary
Half-Life
7.0 days
Time for 50% of the drug to be eliminated
Steady State
~5.0 weeks
Time to reach stable peak/trough levels at each dose
Washout Period
~29 days
Time until less than 3% of peak level remains
Final Peak Level
0.04 mg
Peak drug amount at the stopped (washout) dose
Model Your Own Schedule
Enter your actual doses and timing to see a personalized PK curve with your real data.
Open Semaglutide CalculatorPractical Tips for This Protocol
What to Expect During Washout
The washout period after stopping Semaglutide is gradual. Here is a general timeline based on the 7.0-day half-life:
- Week 1 (days 1-7): Levels drop to roughly 50% of steady-state peak. You may still feel appetite suppression and some GI effects.
- Week 2 (days 8-14): Levels around 25% of peak. Appetite typically starts returning. Some people notice increased hunger during this period.
- Week 3-4 (days 15-28): Levels below 12% of peak. Most drug effects have faded. This is when weight regain becomes a consideration if no dietary or lifestyle changes are in place.
- Week 5+ (day 29+): Levels below 3% of peak, functionally cleared. All drug-related effects should have resolved by this point.
Common Side Effects
In the STEP trials, the most common side effects of semaglutide were gastrointestinal: nausea (44%), diarrhea (30%), and vomiting (24%) at the 2.4mg dose. These effects were generally mild to moderate and most common during dose escalation periods.[2]
Nausea
Most common during the first few days after an injection or dose increase. Smaller meals, bland foods, and staying hydrated can help. Some people find evening injections reduce daytime nausea.
Digestive Changes
Diarrhea or constipation may occur as the drug slows gastric emptying. Adequate fiber, water, and gentle activity help regulate digestion. These effects typically improve within the first 2-3 weeks at each dose.
Reduced Appetite
This is an expected effect, not a side effect. Make sure you are still eating enough protein and nutrients even when appetite is suppressed. Skipping meals entirely can lead to fatigue and muscle loss.
For a comprehensive list including less common effects, see the full Semaglutide side effects guide.
See Your Own Levels
Enter your actual doses and schedule to get a personalized PK curve.
How This Data Was Computed
Levels are modeled using GLP3Planner's pharmacokinetic engine with a 7.0-day half-life (published clinical trial value). The model uses superposition to calculate how weekly doses accumulate over time. Read the full methodology, including clinical data sources and model limitations.
Frequently Asked Questions
How long does Semaglutide stay in your system?
Semaglutide has a half-life of 7.0 days. After your last dose, the drug takes approximately 5 half-lives (35 days) to drop below 3% of peak levels. During this time, effects gradually diminish as the drug clears. Use the Semaglutide calculator to model washout from your specific dose.
What is steady state for Semaglutide?
Steady state is when drug accumulation stabilizes, meaning the amount entering your system each dose roughly equals the amount eliminated between doses. For Semaglutide, this takes approximately 5.0 weeks of consistent dosing at the same level. Once at steady state, your peak and trough levels become predictable from week to week.
What happens if I miss a dose of Semaglutide?
If you miss a dose, take it as soon as you remember if it is within 3 days of your scheduled injection. If more than 3 days have passed, skip the missed dose and take your next one on schedule. Do not double up. Because of Semaglutide's 7.0-day half-life, one missed week reduces but does not eliminate drug levels. It typically takes 2-3 weeks to return to full steady state after a missed dose.
How accurate is the pharmacokinetic data on this page?
The data uses population-average parameters from published clinical trials. Individual drug levels vary based on body composition, metabolism, kidney and liver function, and injection site. The model is most useful for understanding accumulation patterns, steady state timing, and comparing dosing approaches rather than predicting exact personal blood levels. See the full methodology for details.
What is the peak-to-trough ratio and why does it matter?
The peak-to-trough ratio measures how much drug levels fluctuate between injections. A ratio of 4:1 means your peak is four times your trough. Higher ratios mean bigger swings, which some people associate with more side effects at peak and reduced coverage at trough. Split dosing reduces this ratio by producing smaller, more frequent peaks.
Can I use this data to plan my own dosing schedule?
This data is for informational and educational purposes. It shows modeled drug levels for a specific protocol, which can help you understand what to expect and have informed conversations with your doctor. For a schedule tailored to your exact doses, use the interactive Semaglutide calculator.
References
- Jastreboff AM, Kaplan LM, Frias JP, et al. Triple-hormone-receptor agonist retatrutide for obesity: a Phase 2 trial. N Engl J Med. 2023;389(6):514-526. PubMed
- Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. N Engl J Med. 2021;384(11):989-1002. PubMed
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022;387(4):327-340. PubMed
- Novo Nordisk. Ozempic (semaglutide) prescribing information. U.S. Food and Drug Administration. FDA Label
- Eli Lilly and Company. Mounjaro (tirzepatide) prescribing information. U.S. Food and Drug Administration. FDA Label
- Urva S, Coskun T, Loh MT, et al. LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b trial. Lancet. 2022;400(10366):1869-1881. PubMed
- StatPearls. Pharmacokinetics, Steady State. National Center for Biotechnology Information. NCBI Bookshelf
Medical Disclaimer
This page is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or recommendations. The pharmacokinetic data shown is modeled from population-average clinical trial parameters and does not predict individual drug levels. Always consult your doctor before starting, adjusting, or stopping any medication.
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