Semaglutide Tracker: Follow Each Step-Up and the Level Between Shots

What does a semaglutide tracker record?

A semaglutide tracker records the facts you need to answer two questions: what did I take, and what is due next. Each entry holds the date, the time, the dose in milligrams and the injection site. On top of that sits the step you are on in your schedule, because the Ozempic and Wegovy labels both raise the dose in stages.^[1][2] The tracker also holds body weight, the supply left in the pen or vial and your recent doses with how long ago each was. PepTrac adds a next-dose countdown, a reminder at the time you choose and an estimated level curve. It reads the dose you enter and never suggests one. Your prescriber sets the dose and the pace of every step, and the label for your product is the reference for what is normal.

Dose entry

Date, time, milligrams, site and the medicine name you chose.

Current step

The place in the schedule you were given, such as week 5 of a four-week ladder.

Supply

Doses left in the pen or vial, and the date a vial was mixed.

Level estimate

A curve with a shaded range, drawn from your logged doses.

What is the difference between Ozempic and Wegovy?

Both are semaglutide injections from Novo Nordisk, but they carry different labels. The Ozempic label lists glycemic control in type 2 diabetes, a lower risk of cardiovascular events in people with established disease, and a lower risk of kidney disease progression.^[1] The Wegovy label lists weight reduction in adults and in children aged 12 and over, a lower risk of cardiovascular events, and treatment of MASH with moderate to advanced liver fibrosis.^[2] The two products also use different dose ladders, covered below. For a tracker the difference matters in one practical way: the schedule you enter should match the product on your prescription, so label the entry with the brand your pharmacy gave you. PepTrac treats both as semaglutide with one half-life, a property of the molecule. Because the app allows several entries, note that the Zepbound label says use with any GLP-1 receptor agonist is not recommended.^[5]

How does the semaglutide dose step up on the label?

The Ozempic label starts at 0.25 mg once weekly for 4 weeks and then raises the dose to 0.5 mg, with later steps to 1 mg or 2 mg at 4-week intervals.^[1] The Wegovy label uses four-week steps of 0.25, 0.5, 1 and 1.7 mg, then a maintenance dose of either 1.7 mg or 2.4 mg once weekly, with 2.4 mg recommended.^[2] The table lists the Wegovy weeks as the label prints them. These are label facts, not recommendations, and your prescriber may use a different pace. A tracker that stores each step as a dose plus a duration can tell you which step you are on today and when the next one begins. PepTrac does that, and its final step simply holds until you change it. It does not decide when you should move up. That timing belongs to your prescriber, who knows your response.

How long does semaglutide stay in your body?

The Ozempic label gives an elimination half-life of approximately 1 week, which means semaglutide stays in the circulation for about 5 weeks after the last dose.^[1] The same label says the maximum concentration is reached 1 to 3 days after a dose, and that steady-state exposure comes after 4 to 5 weeks of once-weekly dosing.^[1] Those three facts explain why the first weeks of treatment differ from later ones: each shot lands on top of what remains of the last. A half-life is not a measure of how you feel, and it is not a safe-to-stop timer, so ask your prescriber about stopping or restarting. A tracker can turn the half-life into a curve, which is how PepTrac builds its chart. It uses 168 hours as the half-life and 48 hours as the time to peak for semaglutide, both taken from the label ranges. For the arithmetic on its own, see semaglutide half-life.

What does a level estimate look like over the first month?

PepTrac's model shows the build-up clearly. Using the label starting dose of 0.25 mg as an arithmetic input, one dose reads 0.25 at its 48-hour peak and falls to 0.164 by day 7, with a range of 0.138 to 0.184. After four weekly doses the week-4 peak reads 0.485, and the level just before dose five reads 0.307. Those are relative units scaled so a single dose peaks at its own milligrams, not blood concentrations. The shaded range comes from re-running the model with the half-life and peak time each changed by 20 percent, so it measures sensitivity, not statistical confidence. Compare the fourth peak with the first and you see the accumulation the label describes as steady state after 4 to 5 weeks.^[1] The estimate is not a lab result and cannot show how you feel.

How do you track compounded semaglutide in syringe units?

Pens are dialled in milligrams. Compounded vials are drawn in syringe units, so you convert. Concentration is the vial milligrams divided by the millilitres of water, volume is the dose divided by the concentration, and units are the volume times 100 on a U-100 syringe. A 5 mg vial with 2 mL of water is 2.5 mg per mL, so 0.25 mg is 0.1 mL, which is 10 units. That is arithmetic, not a suggested dose. The FDA says it has received reports of dosing errors with compounded semaglutide products and counted 990 adverse event reports for compounded semaglutide as of May 31, 2026.^[4] The semaglutide dose calculator does the conversion, and PepTrac does it inside each compound. It converts the values you enter, so check every result against the product label and with your pharmacist.

How long does a mixed semaglutide vial last in a tracker?

Two different numbers can disagree, so keep both in view. The first is supply: a 5 mg vial holds 20 doses of 0.25 mg, which is 140 days at one dose a week. The second is the clock from the day the vial is first used. The FDA says to discard a multiple-dose vial within 28 days after first use, even if medication remains.^[4] On those figures a vial can hold more doses than the clock allows, so the useful question is how many doses fit inside the window, not how many are left. PepTrac records the date you reconstituted each vial and shows the doses left and the fill level. It does not count down or flag the 28 days, so work out the discard date from the mixed date yourself. Your product label and your pharmacist have the final word on how long a particular vial is good for.

What did the STEP 1 trial measure, and why does it matter for a log?

STEP 1 was a double-blind trial that enrolled 1,961 adults with a body-mass index of 30 or more, or 27 or more with a weight-related condition, and no diabetes. They were assigned two to one to semaglutide 2.4 mg or placebo once weekly for 68 weeks, alongside a lifestyle program.^[3] Mean body weight fell 14.9 percent on semaglutide against 2.4 percent on placebo. Nausea and diarrhea were the most common adverse events, usually mild to moderate and transient.^[3] Novo Nordisk funded the trial, and it is registered as NCT03548935. The takeaway for a log is the time scale: the outcome was measured over 68 weeks, so a long weight trend with dated doses is more informative than any one week. Trial averages describe groups, not you, and they are not a promise of any result.