Zepbound tracker app
Zepbound is tirzepatide, dosed once weekly, with a half-life of about 5 days (120 hours). That single number drives everything a tracker needs to get right: when the next dose is due, how much is still in you if you run late, and why a missed dose is not simply skipped. Bo logs your doses, maps your injection sites, models your estimated level from the published pharmacokinetics, and scans your meals with GLP-1-specific guidance. Free to download.
What a Zepbound tracker should do
- Remember the schedule, not just the dose. Zepbound is once weekly, and weekly is exactly the interval people lose track of.
- Rotate injection sites. The FDA label specifies abdomen, thigh or upper arm with rotation each dose. Why site does not change absorption →
- Handle a late dose sensibly. The labels describe roughly a 48-hour boundary for weekly injectables. What the labels actually say →
- Do the math if you use vials. Pens are pre-measured; compounded vials are not, and getting units wrong is the one error that matters. Free calculator →
- Track what you eat. Appetite is the mechanism, so food logging is not a side feature on a GLP-1.
Levels between doses
With a 5 days (120 hours) half-life and once weekly dosing, tirzepatide never fully clears between injections — each dose stacks on what remains until levels plateau, which takes about 25 days (600 hours) of continuous dosing. Peak concentration arrives around 24 hours after the shot, not the same day, which is why side effects often show up a day or two late.
Bo draws that curve from your own logged doses using these constants, and shows the sources behind them. See the tirzepatide half-life page →
The options
Bo is my app, so here is the honest version. If you take Zepbound as a branded pen and nothing else, Shotsy or MeAgain are larger, longer-established and perfectly good. Bo is the better fit when you reconstitute vials, when you take other peptides alongside it, or when you want the dose countdown on your Lock Screen. Bo has no cloud backup and no Android version — if either matters, choose one of the others.
Educational information only. Bo is a tracking app, not a medical device, and nothing here is medical advice, a dosing recommendation, or a substitute for your prescriber. Half-lives are population averages from the sources cited on each row; individual clearance varies with body weight, kidney and liver function, and other medication.