Free tool

GLP-1 level estimator

See why day 6 can feel nothing like day 2. Pick your medication and shot day to see your estimated level through the week.

Your shot

Shot day
Shots on your current doseThe level builds up over the first 4 to 5 weeks on the same dose.

Estimated level the day before your next shot

62% of peak

WedEstimated peak
100%Level at peak
38Points lost by day 6

An estimate from published half-lives, not a blood test. Math only, not medical advice. Always follow your prescriber's instructions.

How the estimate works

Each shot is absorbed over a day or two, then cleared a little more every day. Embera models that with a standard one-compartment model and the numbers from the prescribing information: a half-life of about 7 days for semaglutide (Wegovy, Ozempic) and about 5 days for tirzepatide (Zepbound, Mounjaro), with a peak 1 to 3 days after a semaglutide shot and 8 to 72 hours after a tirzepatide shot.

The result is shown as a share of your settled peak: 100% is the highest level your dose reaches once you have been on it for several weeks. The dose amount does not change the shape, so you do not need to enter it.

Why day 6 can feel different from day 2

Once your dose has settled, your estimated level still moves through the week. It peaks a day or two after the shot, then eases off until the next one. With a shorter half-life, tirzepatide moves more across the week than semaglutide.

Day after the shotSemaglutideTirzepatide
Shot day87%87%
Day 199%95%
Day 292%83%
Day 383%73%
Day 476%63%
Day 568%55%
Day 662%48%

Average estimated level over each day, once the dose has settled, as a share of the peak. Many people describe food noise or appetite coming back in the last days before their shot. The lower level late in the week is one possible piece of that, not the whole story.

What this cannot tell you

  • It does not measure anything in your body. Weight, metabolism and where you inject change real levels from person to person.
  • It does not tell you when to take your shot or how much. Your prescriber decides that.
  • A missed or late shot changes the curve. If that happens, follow the instructions that came with your medication or ask your pharmacist.

Sources: prescribing information for Wegovy, Ozempic, Zepbound and Mounjaro (clinical pharmacology section). Brand names belong to their owners. Embera is not affiliated with Novo Nordisk or Eli Lilly.

Last updated September 26, 2026. Same formulas as the Embera app.

Questions

Is this my real blood level?

No. It is an estimate from the published half-life and absorption of your medication, shown as a share of the highest level your dose reaches once it has settled. Only a lab test measures a real blood level, and nobody needs one to take a GLP-1.

Why does the dose amount not change the percentage?

The percentage compares your level with the peak of the same dose once it has settled. A bigger dose raises both at the same rate, so the shape of your week stays the same. What changes the shape is the medication (its half-life) and how many weeks you have been on the dose.

Why is the level lower in my first weeks on a dose?

Each shot adds to what is left from the last one. With a half-life of about 5 to 7 days, it takes around 4 to 5 weeks on the same dose for the level to settle. That is why the estimate is lower after your first shots.

Does a lower level late in the week explain my hunger?

It can be one piece of it. Many people describe food noise coming back before shot day, and the estimated level is lowest then. Sleep, stress, meals and your cycle play a part too. Logging how you feel next to your shots is the only way to see your own pattern.

Does it work for pills like Rybelsus?

This page is for weekly injections. Daily pills are taken every day, so the level stays much flatter through the week. The Embera app estimates both.

In the Embera app

Embera draws this curve from the shots you actually log, including late or missed ones, pills and dose changes, free. Embera Pro lines it up with your food noise check-ins to show your own pattern.

See what the app does

More free tools

Mixing & syringe converterTurn the dose on your prescription into syringe units, or plan how much water to add.Pen & vial run-out dateFind the date your supply runs out and when to order the refill.Injection site rotation chartA printable rotation chart with your dates filled in.Protein & fiber benchmarkA general daily protein and fiber benchmark for your weight, split by meal.Shot day plannerSee how each possible shot day lines up with the days that matter in your week.

Track it every week, not just once.

Embera does this math for you from what you log. Free to use, no account, your data stays on your iPhone.

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