Mounjaro is licensed for once-weekly dosing, but the interval between injections affects how steady your medication levels are. Tirzepatide has a long half-life of about five days, so levels rise after each dose and fall before the next — the gap between the highest (peak) and lowest (trough) level is the 'fluctuation'.
What changes with a shorter interval
Injecting a smaller dose more often — say 2.5mg every five days instead of 5mg weekly — generally produces a lower peak while keeping a similar trough, which some people find easier on side effects. The total weekly amount can be similar, but the curve is smoother.
The trade-off is more frequent injections and more bookkeeping. It's also off-label, so only do it with your prescriber's agreement.
Model it before you decide
The calculator's estimated-levels chart lets you overlay two schedules and compare their peak, trough and average side by side. It's an estimate based on average pharmacokinetic data — individual responses vary — but it's a useful way to see the shape of each option before discussing it with your clinician.