Free Tool
Mounjaro Half-Life Calculator
Visualize when your Mounjaro (tirzepatide) peaks, track your medication levels over time, and optimize your injection schedule. Tirzepatide has a half-life of approximately 5 days.
How This Calculator Works
Pharmacokinetic Model
Uses a clinically-validated one-compartment pharmacokinetic model with first-order absorption and elimination. Based on published half-life and bioavailability data for each medication.
Personalized Calculations
Adjusts for your body weight to calculate volume of distribution. Heavier individuals have different concentration curves than lighter individuals, even at the same dose.
Evidence-Based
All medication parameters sourced from FDA prescribing information and peer-reviewed pharmacokinetic studies. We use published data, not estimates or guesses.
Understanding Your Medication Levels
What is Half-Life?
Half-life is the time it takes for your body to eliminate 50% of the medication. Semaglutide (Ozempic, Wegovy) has a half-life of approximately 7 days, while Tirzepatide (Mounjaro, Zepbound) has a half-life of about 5 days. This is why you inject weekly—medication levels remain elevated between doses, providing continuous appetite suppression and blood sugar control.
Why Peak and Trough Levels Matter
Understanding when your medication peaks and drops helps you optimize your GLP-1 experience:
- Peak Levels (highest concentration) typically occur 1-3 days after injection and correlate with the strongest side effects (nausea, fatigue). This is also when appetite suppression is most powerful.
- Trough Levels (lowest concentration) occur just before your next dose and may result in increased hunger or reduced fullness. Some people describe this as "food noise" returning.
How to Use This Information
Use your medication level graph to make informed decisions:
- • Meal Planning: Eat light, protein-rich meals when levels are high to minimize nausea
- • Activity Scheduling: Avoid intense exercise or social events during peak days if you experience fatigue
- • Timing Optimization: Consider injecting in the evening if you experience daytime side effects—this shifts the peak to nighttime when you're sleeping
- • Steady State: After 4-5 doses, your levels will reach steady state, and side effects often improve as your body adapts
Tips for Using This Information
Plan Meals Around Peak Times
When your levels are highest (1-3 days after injection), prioritize protein-rich, easy-to-digest meals. Avoid high-fat or fried foods during this window to minimize nausea. Save challenging social meals for when levels are moderate.
Track Side Effects
Keep a journal of side effects and compare them to your medication level graph. You may notice patterns—like nausea always occurring on Day 2-3. This knowledge helps you prepare and adjust your schedule accordingly.
Optimize Injection Timing
If you experience daytime nausea, try switching to evening injections. This shifts your peak to nighttime when side effects are less disruptive. Experiment to find what works best for your lifestyle.
Discuss with Your Doctor
Share your graph with your healthcare provider. If you experience a large trough-to-peak swing, they may recommend a shorter dosing interval (e.g., every 5 days instead of weekly) for more consistent coverage.
Frequently Asked Questions
Medical Disclaimer
This calculator is for educational and informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. The medication concentration calculations are based on published pharmacokinetic data and population averages. Individual responses to medication vary based on many factors including genetics, metabolism, kidney and liver function, body composition, other medications, and medical conditions. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have seen on this calculator. If you think you may have a medical emergency, call your doctor or emergency services immediately.
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