How often should you inject Retatrutide?

Retatrutide is typically injected once weekly due to its long half-life of approximately 6 days.

How long until Retatrutide reaches steady state?

With a half-life of approximately 6 days, Retatrutide reaches steady state after about 4-5 weeks of consistent weekly dosing. Steady state means drug levels stabilize with consistent peaks and troughs.

Stability Window Details

Stable window reached: -

Average stable amount: - mg

Stable window days

Date	Day	Amount in Body

Retatrutide Calculator: Track Dose Levels & Reach Steady State

// HOW IT WORKS

How the Retatrutide Calculator Works

This free Retatrutide calculator uses pharmacokinetic modeling to track your triple agonist levels over time. Enter your dose and schedule to see how the drug builds up in your system.

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Retatrutide Half-Life Calculator

With a 6-day half-life, see how concentration peaks after each injection and decreases between doses.

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Steady State Prediction

Know when you'll reach steady state (typically 4-5 weeks on retatrutide) where drug levels stabilize.

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Visualize Drug Levels

Interactive chart shows retatrutide concentration from your first dose through maintenance at 12mg.

Retatrutide Dosing Guide

Retatrutide is a triple agonist targeting GLP-1, GIP, and glucagon receptors simultaneously. In Phase 2 trials, the 12mg dose produced 24% average weight loss at 48 weeks, more than any other GLP-1 studied so far. The standard dosing protocol starts at 2mg weekly, increasing every 4 weeks to minimize GI side effects like nausea and diarrhea. Doses climb to the maintenance dose of 12mg over 12-16 weeks. Each tier takes about 4-5 weeks to reach steady state concentration.

Standard Retatrutide Dosage Chart

Tier	Weekly Dose	Duration
1	2 mg	4 weeks
2	4 mg	4 weeks
3	8 mg	4 weeks
4	12 mg	Maintenance

Key Facts About Retatrutide

Half-life: Approximately 6 days
Mechanism: Triple agonist (GLP-1/GIP/Glucagon receptors)
Administration: Once weekly subcutaneous injection
Steady State: Reached after 4-5 weeks of consistent dosing

Note: Retatrutide is currently in clinical trials. Individual dosing may vary. Always follow guidance from your healthcare provider.

// FAQ

Retatrutide Calculator FAQ

What is the half-life of Retatrutide?

Retatrutide has a half-life of approximately 6 days. This means after 6 days, about 50% of the drug remains in your system. The triple GLP-1/GIP/Glucagon mechanism works throughout this period for metabolic effects.

How long does Retatrutide stay in your system?

After stopping retatrutide, it takes approximately 5 half-lives (about 30 days) for the drug to be essentially cleared from your system. Metabolic effects may continue during this washout period.

Is compounded Retatrutide the same?

Compounded retatrutide contains the same active molecule with the same 6-day half-life. However, compounded versions may vary in concentration and purity. This calculator works with any retatrutide source; simply enter your actual dose.

Get started in seconds with our pre-built titration templates, or build your own custom schedule below.

Statistics

Peak Amount

Today's Amount

Average Stable Amount

Days until stable Click to learn how stability is calculated

Total Administered Complete Plot

Total Administered so far

Out of System (<0.02mg)

Weight Trend

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Drug Amount Plot

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Generate a schedule and click "Generate Plot" to visualize

What's a half-life?

The time your body needs to clear half a dose. After about five half-lives, a single dose is essentially gone. Tirzepatide has a half-life of roughly 5 days, so one dose takes about 25 days to clear; Semaglutide is closer to 7 days; Retatrutide is about 6 days.

Read the full half-life guide

What's steady state?

The point where what you take in each week equals what your body clears. Most weekly GLP-1s reach it after 4–5 weeks of consistent dosing — that's when blood levels stop climbing and the chart flattens out.

Read the full steady-state guide

Dose Schedule

Week	/Week	Date	Day	Time	Vial	IU	Dose (mg)	Weight (kg)	Journal	Actions

Configure your schedule below and click "Generate Schedule" to begin

Configure Dose Schedule

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