Short answer: Dulaglutide has a half-life of about 5 days (Trulicity (dulaglutide) label) and reaches steady state after about 25 days (~3.6 weeks) of regular dosing. Levels peak about 2 days after an injection under the skin. On a weekly schedule the model builds up to about 1.6× a single dose, with a peak-to-trough swing of about 1.89:1.
The Trulicity label starts at 0.75 mg once weekly. Source: Trulicity (dulaglutide) label. Bioavailability 50% as in the app. Dashed line: 5 half-lives. Change the amount or schedule in the calculator.
Levels peak about 2 days after an injection under the skin.
With regular dosing at a fixed amount and interval, levels climb toward steady state by the same fraction every half-life, whatever the dose. At a half-life of about 5 days:
| Share of steady state | Half-lives | Time |
|---|---|---|
| 50% | 1 | 5 days |
| 75% | 2 | 10 days |
| 90% | 3.3 | 16.6 days |
| 97% (Dose Track's steady-state rule) | 5 | 25 days (~3.6 weeks) |
The longer the gap between doses compared with the half-life, the bigger the swing from peak to trough and the less the levels build up. These ratios do not depend on the amount.
| Interval | Peak : trough | Build-up vs one dose |
|---|---|---|
| Daily | 1.02 : 1 | 7.73× |
| Every other day | 1.08 : 1 | 4.13× |
| Twice weekly | 1.24 : 1 | 2.6× |
| Weekly | 1.89 : 1 | 1.61× |
| Every 2 weeks | 4.78 : 1 | 1.17× |
Build-up is the accumulation ratio 1 / (1 − e−k·τ), with k = ln 2 / half-life and τ the interval.
After the last dose, about half is gone every 5 days. After 5 half-lives, about 25 days (~3.6 weeks), roughly 97% has cleared in the model.
The FDA Trulicity label gives an elimination half-life of about 5 days and a time to peak of 24 to 72 hours at steady state, with a median of 48 hours.
The curve uses the half-life, time to peak, route and bioavailability built into the Dose Track app for dulaglutide, and the same one-compartment model with first-order absorption. These are modeled estimates from published half-lives, drawn with the same one-compartment model as the Dose Track app. Real levels vary from person to person, and only a lab test measures them. This is not medical advice and not a dosing recommendation; dosing decisions belong with you and your prescriber.
Vial sizes and syringe math are in the Dulaglutide guide.
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