How this works
The math
How the arithmetic works
per injection = weekly mg × days between ÷ 7Twice a week: each amount = weekly mg × days from that weekday to the next chosen weekday ÷ 7.units = per injection ÷ strength in mg/mL × 100 (U-100 only)For example, 10 mg a week every 5 days is 7.142857 mg per injection, shown as 7.14 and marked as rounded. The arithmetic keeps the weekly average the same. It says nothing about what a different schedule does in your body.
What the label shows
- Moving your weekly day
- Zepbound and Mounjaro say to keep two doses at least 3 days (72 hours) apart, and Ozempic at least 2 days (more than 48 hours).235 These rules cover moving a weekly day. They don’t approve a shorter schedule. For numerical reasons, the arithmetic accepts intervals of 0.1 days or longer and shows warnings; a calculated result does not approve a shorter schedule.
- Single-dose pens and vials
- Single-dose devices still get arithmetic, not permission to divide or reuse them. Follow the device instructions; a single-dose pen delivers its full dose.
- Multi-dose vials
- Zepbound’s label says to throw away an opened multi-dose vial after 30 days, or after 4 weekly doses, even if medicine is left.2 FDA says to discard a compounded multiple-dose vial within 28 days after first use.1
- Going beyond the label
- FDA lists using more product in a single dose, taking doses more frequently and increasing the amount more quickly among the ways compounded products have been used beyond the label, with reports of adverse events.1
- This page
- This page shows a dated arithmetic calendar from your chosen start date, not a treatment plan. Your prescriber decides any actual schedule.
- Regional changed-day limits
- These are rules for moving a weekly day, not approval for repeating a shorter schedule. In the EU, Wegovy and Ozempic specify at least 3 days (more than 72 hours); Mounjaro specifies at least 3 days. In Japan, Wegovy specifies at least 72 hours. A choice of every 3 days here does not establish that a label’s changed-day rule is met.6789
Before you act on this
One FDA report describes a patient, who was a health care provider, recalculating their own dose in units and taking 10 times what they meant to.10 Don’t act on a number you worked out yourself until your prescriber has confirmed it.
Took more than you were prescribed? Call your prescriber or pharmacist now. In the US, Poison Help is 1-800-222-1222. Severe vomiting, severe nausea or signs of low blood sugar need urgent care.
Something went wrong, or a vial looks or acts wrong? Tell your prescriber. In the US, you can also report it to FDA’s MedWatch program.1
Always follow your doctor’s or prescriber’s advice and guidance. Talk to your prescriber before changing your dose.
Read this first
No label supports a split schedule
- Zepbound, Mounjaro, Wegovy and Ozempic are each labeled for once-weekly dosing.2345 Nothing on this page shows that another schedule works or is safe.
- FDA has adverse event reports, some serious, that may be related to compounded semaglutide or tirzepatide used beyond the label, including taking doses more often.1
- The number below is not a dose to take. Don’t change your schedule on your own. Take it to your prescriber, and ask whether any change is right for you.
For information only, not medical advice. Verify results with your healthcare provider; Onederland accepts no liability for use of these tools.
- Runs on this device. Nothing you type is sent anywhere.
- Every figure names its source, below.
- Education, not medical advice. Your prescriber comes first.
Sources
Sources
- FDA: concerns with unapproved GLP-1 medicines, October 1, 2026. fda.gov
- Zepbound (tirzepatide) injection, US prescribing information, revised 08/2026. accessdata.fda.gov
- Mounjaro (tirzepatide) injection, US prescribing information, revised 08/2026. accessdata.fda.gov
- Wegovy (semaglutide) injection and tablets, US prescribing information, revised 06/2026. accessdata.fda.gov
- Ozempic (semaglutide) injection, US prescribing information, revised 05/2026. accessdata.fda.gov
- EU product information for semaglutide for weight management (tablets: summary of product characteristics, section 4.2), updated 21 September 2026. ema.europa.eu
- EU product information: injectable semaglutide for type 2 diabetes. ema.europa.eu
- EU product information: tirzepatide. ema.europa.eu
- Japanese prescribing information: injectable semaglutide for obesity, June 2026. pmda.go.jp
- FDA: dosing errors with compounded injectable semaglutide, July 26, 2024. fda.gov
Label sources last checked on October 30, 2026. Onederland summarizes them; your prescriber and the full prescribing information come first.
