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Feature

The Cycle View

On a weekly injection, no two days are the same — and the reason is the medicine's own rhythm. The Cycle View draws that rhythm from the dose dates you log and the published half-life, so that the day you felt worst, or the evening your appetite came back, can be read against where you were in the cycle.

By the Cafeity teamUpdated

The short answer

The Cycle View is an estimated medication level drawn from the dates of the doses you log and the published half-life of your medicine — about a week for semaglutide, about 5 days for tirzepatide, about 13 hours for liraglutide and 29 to 49 hours for orforglipron.1234 Every dose is modelled as decaying by half each half-life, and the doses are added together. It is labelled on screen as an estimate, not a measurement, and it is never used to suggest when or how much to take. It is part of Cafeity Pro.

Chart of a modelled weekly-injection level across eight weekly doses with a one-week half-life: it rises for the first four to five weeks and then repeats a saw-tooth between about one and two times a single dose.
The model behind the Cycle View: weekly doses, a one-week half-life, each dose halving every week and added to the rest. Relative to a single dose. The app draws the same curve from your own dates.

How it is worked out

The model is deliberately simple, and fully disclosed: each dose you log contributes a level that halves every half-life, and the contributions are summed. In full, level(t) = Σ 0.5 ^ ((t − tdose) / half-life). That is all. It knows nothing about your blood, your kidneys or your metabolism, and the published half-life is a population average.

The same arithmetic is on the half-life calculator, where you can check any figure the app shows.

What it is for

  • Reading symptoms against the cycle — is nausea worst a day or two after the injection, when the model peaks?
  • Reading appetite and food noise — does hunger come back as the model falls towards the next dose? See food noise.
  • Understanding the first weeks — the level builds for weeks before it settles, so week one and week eight are not comparable.
  • Seeing the effect of a gap — a late or missed dose shows as a lower curve, which helps explain the days after it.

What it is not

It is not a blood test, not a prediction and not dosing information. Cafeity will never use it to suggest when to inject, how much to take, or whether to change anything — some apps market dose timing from exactly this kind of curve, and Cafeity deliberately does not, because a population model is nowhere near precise enough to time a medicine. The chart says "estimate" on the screen, every time.

Medicines it models

Published half-lives from each medicine's US prescribing information.
MedicineHalf-life on the labelUsual interval
SemaglutideAbout 1 weekWeekly injection or daily tablet
TirzepatideAbout 5 to 6 daysWeekly injection
DulaglutideAbout 5 daysWeekly injection
LiraglutideAbout 13 hoursDaily injection
OrforglipronAbout 29 to 49 hoursDaily tablet
Exenatide (twice daily)About 2.4 hoursTwice-daily injection

Sources: prescribing information for each medicine.125346

What it will never do

  • Recommend, calculate or adjust a dose, or tell you when to take one.
  • Interpret a symptom, name a condition, or suggest what is causing something.
  • Predict how much weight you will lose, or when.
  • Set a calorie target below 1,200 kcal, or a weight goal below a BMI of 18.5.

Cafeity is a general wellness product. It does not diagnose, treat, cure, mitigate or prevent any disease or condition. Questions about your treatment belong with a licensed healthcare professional.

Keeping a record of it

Screens from Cafeity on iPhone.

Cafeity medication-level chart over seven days, labelled "Estimate based on published half-life. Not a measurement", with the last dose, the injection site (stomach, upper left), the next scheduled dose and a side-effect check-in.
The estimated level across the week.
Cafeity dose screen: an estimated medication-level curve labelled "Estimate based on published half-life. Not a measurement", the last dose, the injection site (stomach, lower left), a countdown to the next scheduled dose and a side-effect check-in.
The dose record it is drawn from.

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Common questions

Is the Cycle View my actual blood level?
No. It is a schedule model from your logged dose dates and a published population half-life. Individual pharmacokinetics vary; treat it as a description of your week, not a measurement.
Will the Cycle View tell me when to inject?
No, and it never will. Timing a dose from a population model is a clinical decision the model cannot support.
Is the Cycle View free?
It is part of Cafeity Pro. Logging doses is free.

Sources

  1. Semaglutide injection and tablets for weight management — US prescribing information DailyMed, US National Library of Medicine, version published 30 June 2026
  2. Tirzepatide injection for weight management and obstructive sleep apnoea — US prescribing information DailyMed, US National Library of Medicine, version published 2 September 2026
  3. Liraglutide 3 mg injection for weight management — US prescribing information DailyMed, US National Library of Medicine, version published 15 June 2026
  4. Orforglipron tablets for weight management — US prescribing information DailyMed, US National Library of Medicine, version published 13 August 2026
  5. Dulaglutide injection — US prescribing information DailyMed, US National Library of Medicine, version published 10 August 2026
  6. Exenatide twice-daily injection — US prescribing information DailyMed, US National Library of Medicine, version published 8 September 2025

Written by the Cafeity team from the sources listed here. Figures from prescribing information are quoted as the label states them; trial results are averages from those trials, not predictions for any one person. This page has not yet been reviewed by a clinician — see the editorial policy for how pages are researched and corrected.