Quick answer: In the model, skipping one weekly dose of Retatrutide lets your level fall 56% below your usual low before your next dose. Levels are back within 10% of the on-schedule curve about 3 weeks after the missed dose (about 2 weeks after you restart). A dose 1 day late barely moves the curve: the dip is 11% below the usual low.
What happens if you skip a week of reta?
Retatrutide has a half-life of about 6 days, so each weekly dose is still partly in your system when the next one lands. Doses stack until they level off at a plateau. Skip one and that dose's share is simply missing: your level keeps falling past its usual low until your next dose, and the peaks after you restart run lower until the missing dose would have cleared anyway.
Nothing resets. The doses before the miss are still clearing, so you do not rebuild from zero. A single skipped week costs one dose's worth of drug, and that deficit fades on the same half-life clock as everything else, which is why recovery takes weeks rather than months.
Taking reta late instead of skipping
A late dose moves that dose's curve instead of removing it. The sooner you take it, the smaller the dip before it. But the late dose then lands closer to your next scheduled one, so the two overlap and the next peak runs higher than usual. In the table above, a dose 1 day late puts the next peak 3% above usual; at 6 days late it is 26% above usual. This tool models the late dose followed by your next dose on your usual day.
What the label says
There is no label rule for Retatrutide. It is investigational and not FDA-approved, so no prescribing information sets a missed-dose window. This calculator does not invent one: it shows modelled levels for a skipped or late dose and leaves the decision to you and whoever supervises your use.
Frequently asked questions
What happens if I skip a week of reta?
In the model, skipping one weekly dose of Retatrutide lets your level fall 56% below your usual low before your next dose, and the first peak after you restart runs 26% below your usual peak. Levels are back within 10% of your on-schedule curve about 3 weeks after the missed dose. Enter your own dose and week above to see your curve.
Can I take reta a day late?
Retatrutide is investigational and has no FDA label, so there is no official missed-dose window, and this tool does not tell you whether to take a late dose. In the model, a dose 1 day late lets your level dip 11% below your usual low, puts the next peak 3% above your usual peak, and is back within 10% of your on-schedule curve in 2 days.
Does my dose change how long recovery takes?
No. The model is linear, so the percentage drop and the time to recover are the same at every dose; your dose only sets the mg scale on the chart. What changes the answer is whether you skipped the dose or took it late, and how late.
How is this calculated?
A one-compartment model with first-order absorption, the same model as the GLP3 Planner half-life calculator. For Retatrutide: half-life about 6 days, time to peak 1.5 days, and 80% bioavailability. Retatrutide has no FDA label: the time to peak is the calculator's own assumption and the bioavailability is inferred from tirzepatide, so treat its figures as approximate. Every dose's curve is added together, and the skipped or late dose is compared with the same schedule taken on time.
The full methodology lists every model parameter and its source.
Safety: Retatrutide is an investigational compound and is not approved by the FDA. This tool is educational only. It models population-average drug levels, not your own, and it does not tell you whether to take, skip, or double a dose. For a missed dose, follow your prescriber's or pharmacist's instructions.