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Compounded GLP-1 doses vs label doses: units, mg and errors

Updated Sep 27, 2026. Numbers in brackets link to the source each fact comes from.

The FDA-approved labels for Wegovy and Zepbound set every dose in milligrams and say how many weeks to wait between steps. Compounded semaglutide and tirzepatide are not FDA-approved [26], so no FDA label sets their dose, and the FDA has adverse event reports from people given compounded versions at doses beyond the approved labels: larger single doses, more frequent doses or faster increases [1]. It also has reports of patients injecting 5 to 20 times the intended dose after reading instructions written in “units” [8].

This page compares the two and explains where the errors come from. It is not dosing advice; your prescriber sets your dose.

The label doses: Wegovy

Wegovy injection, once a week [14]:

Weeks Dose
1 to 4 0.25 mg [14]
5 to 8 0.5 mg [14]
9 to 12 1 mg [14]
13 to 16 1.7 mg [14]
17 onward 1.7 mg or 2.4 mg (2.4 mg recommended) [15]

After at least 4 weeks on 2.4 mg, the dose may go up to a maximum of 7.2 mg if more weight loss is clinically needed [16]. If a step is not tolerated, the label says to consider waiting 4 weeks before going up [17].

Wegovy tablets, once a day: 1.5 mg for days 1 to 30, 4 mg for days 31 to 60, 9 mg for days 61 to 90, then 25 mg [18].

The label doses: Zepbound

Zepbound starts at 2.5 mg once a week for 4 weeks [19], and that starting dose is not approved for long-term use [20]. After that the dose goes to 5 mg and can rise in 2.5 mg steps, with at least 4 weeks at each dose [21]. Maintenance doses for weight loss are 5 mg, 10 mg or 15 mg a week [22], and 15 mg is the maximum [23]. If a maintenance dose is not tolerated, the label says to consider a lower one [27].

Why compounded doses go wrong

Approved semaglutide injections come in pre-filled pens at standard strengths, dosed in milligrams; compounded semaglutide comes in different concentrations [3], and even one compounder may sell several [5]. Instructions may tell you to inject a number of “units” instead of milligrams, and how much drug is in a unit depends on the concentration of that vial [4]. A unit on an insulin syringe is a measure of volume: in the FDA’s reports, 5 units on a U-100 syringe was 0.05 mL [6].

The FDA describes what happened next:

  • Patients told to draw 5 units drew 50 units instead [7].
  • Most reports involved patients drawing too much from a multi-dose vial and taking 5 to 20 times the intended dose [8].
  • Some prescribers converted milligrams to units wrongly, and patients took 5 to 10 times the intended dose [9]. In one case a prescriber meant 0.25 mg, which was 5 units, but wrote 25 units; the patient had severe vomiting [10].

What an overdose can do

The FDA lists severe nausea, severe vomiting and low blood sugar, and notes that semaglutide stays in the body for about a week, so observation and treatment may take a while [11]. Among reports tied to doses beyond the label, symptoms included nausea, vomiting, diarrhea, abdominal pain and constipation [2].

Some compounders also add vitamins B12 or B6, L-carnitine or NAD to semaglutide [13]. The FDA says the safety and effectiveness of those combinations has not been established [13].

If you have a compounded prescription

  • Ask your prescriber or the compounding pharmacy to confirm the dose in milligrams, the concentration of your vial and the exact amount to draw. The FDA encourages exactly that conversation [12].
  • Do not convert units to milligrams yourself, and do not change your dose based on a chart from a website.
  • The FDA tells prescribers to be careful with compounded doses and how fast they go up [25]. If your plan climbs faster than the label steps above, ask why.
  • Moving to a brand-name product is a new prescription. The Wegovy label explains switching between its own tablets and injection, such as going from 25 mg tablets to the 2.4 mg injection [24]; it gives no conversion from compounded products, so your prescriber decides where you start.

For the approved doses of all five brand-name GLP-1s side by side, see GLP-1 dosing compared. For why the FDA treats compounded versions differently, see what the FDA says about compounded semaglutide and tirzepatide.

Sources

  1. Additionally, the agency has received adverse event reports that may be related to patients prescribed compounded semaglutide or tirzepatide products in doses beyond what is in the FDA-approved drug label. This could mean using more product in a single dose, taking doses more frequently or increasing the amount more quickly (titration schedule). fda.gov, read Sep 27, 2026.
  2. Some of the adverse events are serious and some patients reported seeking medical attention for their symptoms, including nausea, vomiting, diarrhea, abdominal pain and constipation. fda.gov, read Sep 27, 2026.
  3. FDA-approved injectable semaglutide products are dosed in milligrams, have standard concentrations and are currently only available in pre-filled pens. FDA is aware that compounders provide semaglutide in various concentrations. fda.gov, read Sep 27, 2026.
  4. Additionally, the instructions that accompany the compounded drug, if provided, may instruct users to administer semaglutide injections in “units” (the volume of which may vary depending on the concentration), rather than milligrams or milliliters. fda.gov, read Sep 27, 2026.
  5. Product concentrations also may vary depending on the compounder, and a single compounder may offer multiple concentrations of compounded semaglutide products. fda.gov, read Sep 27, 2026.
  6. In several reports, patients were instructed to use a U-100 (1 milliliter) insulin syringe to draw small doses, such as a 5-unit (0.05 milliliter) dose, from a multiple-dose vial. fda.gov, read Sep 27, 2026.
  7. As depicted in the figure below, these patients were directed to administer 5 units from a vial. However, these patients mistakenly administered 50 units instead. fda.gov, read Sep 27, 2026.
  8. The majority of the reports described patients mistakenly drawing up more than the prescribed dose from a multiple-dose vial during self-administration. In these instances, patients administered five to 20 times more than the intended dose of semaglutide. fda.gov, read Sep 27, 2026.
  9. Several reports describe health care providers incorrectly calculating the intended dose when converting from milligrams to units or milliliters, which resulted in patients administering five to 10 times more than the intended dose of semaglutide. fda.gov, read Sep 27, 2026.
  10. One provider intended to dose 0.25 milligrams (5 units), but prescribed 25 units instead, leading to a patient receiving five times the intended dose and experiencing severe vomiting. fda.gov, read Sep 27, 2026.
  11. Adverse effects include severe nausea, severe vomiting and severe hypoglycemia (low blood sugar levels). A prolonged period of observation and treatment for overdose symptoms may be necessary due to the long half-life of semaglutide of about one week. fda.gov, read Sep 27, 2026.
  12. FDA encourages patients to talk with their health care provider or compounder about how to measure and administer the intended dose of compounded semaglutide. fda.gov, read Sep 27, 2026.
  13. FDA is aware that some compounders incorporate additional ingredients, such as cyanocobalamin (Vitamin B-12), pyridoxine (Vitamin B-6), levocarnitine (L-Carnitine) and nicotinamide adenine dinucleotide (NAD), into their semaglutide products. The safety and effectiveness of combining semaglutide with other ingredients has not been established. fda.gov, read Sep 27, 2026.
  14. Starting Dosage 1 through 4 0.25 mg Dosage Escalation 5 through 8 0.5 mg 9 through 12 1 mg 13 through 16 1.7 mg Maintenance Dosage 17 and onward See the indication below for the recommended maintenance dosage(s) dailymed.nlm.nih.gov, read Sep 27, 2026.
  15. The maintenance dosage of WEGOVY for weight reduction in adults is either 1.7 mg or 2.4 mg (recommended) injected subcutaneously once weekly. dailymed.nlm.nih.gov, read Sep 27, 2026.
  16. For patients who tolerate the 2.4 mg dosage for at least 4 weeks and additional weight reduction is clinically indicated, the dosage may be increased to a maximum dosage of 7.2 mg subcutaneously once weekly. dailymed.nlm.nih.gov, read Sep 27, 2026.
  17. If patients do not tolerate a dose during dosage escalation, consider delaying dosage escalation for 4 weeks. dailymed.nlm.nih.gov, read Sep 27, 2026.
  18. Starting Dosage 1 through 30 1.5 mg Dosage Escalation 31 through 60 4 mg 61 through 90 9 mg Maintenance Dosage 91 and onward 25 mg dailymed.nlm.nih.gov, read Sep 27, 2026.
  19. The recommended starting dosage of ZEPBOUND for all indications is 2.5 mg injected subcutaneously once weekly for 4 weeks. dailymed.nlm.nih.gov, read Sep 27, 2026.
  20. The 2.5 mg dosage is for treatment initiation and is not approved as a maintenance dosage. dailymed.nlm.nih.gov, read Sep 27, 2026.
  21. After 4 weeks, increase the dosage to 5 mg injected subcutaneously once weekly. The dosage may be increased in 2.5 mg increments, after at least 4 weeks on the current dose dailymed.nlm.nih.gov, read Sep 27, 2026.
  22. Weight Reduction and Long-Term Maintenance: 5 mg, 10 mg, or 15 mg injected subcutaneously once weekly. (2.2) dailymed.nlm.nih.gov, read Sep 27, 2026.
  23. The maximum dosage of ZEPBOUND for all indications is 15 mg injected subcutaneously once weekly. dailymed.nlm.nih.gov, read Sep 27, 2026.
  24. The day after discontinuing WEGOVY tablets 25 mg once daily, initiate WEGOVY 2.4 mg subcutaneous injection once weekly. dailymed.nlm.nih.gov, read Sep 27, 2026.
  25. Health care providers should be vigilant when prescribing compounded semaglutide or tirzepatide products and determining appropriate doses and titration and dosing schedules for patients. fda.gov, read Sep 27, 2026.
  26. However, compounded drugs are not FDA approved. This means the agency does not review compounded drugs for safety, effectiveness or quality before they are marketed. fda.gov, read Sep 27, 2026.
  27. Consider treatment response and tolerability when selecting the maintenance dosage. If patients do not tolerate a maintenance dosage, consider a lower maintenance dosage. dailymed.nlm.nih.gov, read Sep 27, 2026.

This page reports what official sources say; it is not medical advice. Medical disclaimer.