Semaglutide dosage chart in units for injectable semaglutide

Any table of semaglutide dosage chart units is built on a single concentration. Five steps turn the dose your clinician wrote into a line on your syringe. This is the same math as Arbor's guide on how to measure tirzepatide in units, because a U-100 syringe measures both medicines the same way.

Order matters. FDA reports describe people drawing five to 20 times their intended dose from compounded semaglutide vials after confusing milligrams, milliliters and units.

1. 01

   Step 1: Find the concentration on your vial label

   Look for a figure written in mg/mL: how many milligrams of semaglutide sit in each milliliter of liquid. Some labels give a total instead, milligrams in a number of milliliters, and you divide one by the other. On the Wegovy FlexTouch pen label, for example, 9.6 mg sits in 3 mL, which works out to 3.2 mg/mL. Check your name, the drug, the expiry date and the date you opened it too. According to the FDA, one compounder may offer several concentrations, so a refill can look identical and still be different.

   No concentration on the label means no chart applies. Message your care team before you draw.

2. 02

   Step 2: Convert your semaglutide dose from mg to units

   Semaglutide mg to units takes one formula: units to draw = (dose in mg / concentration in mg/mL) x 100. Dividing gives you milliliters. Multiplying by 100 turns milliliters into units on a U-100 syringe, where 100 units equals 1 mL. Take a 0.5 mg dose from a vial labeled 2.5 mg/mL, an example concentration used only to show the math. Divide 0.5 by 2.5 to get 0.2 mL, then multiply by 100 to get 20 units.

   Your answer should match the units your clinician wrote. If it does not, stop and ask.

3. 03

   Step 3: Match your dose to the syringe markings

   A U-100 syringe is marked in units, not milligrams. Sizes differ, and so can the space between the small lines, so read the numbers printed on the barrel and confirm what one small line equals on yours before you count. Use the syringe your pharmacy sent. FDA reports include patients handed syringes far larger than their dose, and several in which a 5-unit dose (0.05 mL) was drawn as 50 units. Read the line at eye level in good light. Arbor's guide to inject semaglutide at home covers drawing from the vial and giving the shot.

4. 04

   Step 4: Follow the dosing schedule your clinician sets

   Your semaglutide dosing schedule comes from your clinician, not from a chart. The FDA-approved Wegovy label sets the reference ladder for brand semaglutide: 0.25 mg once weekly for weeks 1 to 4, then 0.5 mg, 1 mg and 1.7 mg for four weeks each, and a maintenance dose of 1.7 mg or 2.4 mg from week 17. Adults who have tolerated 2.4 mg for at least four weeks can now go up to a maximum of 7.2 mg when more weight reduction is clinically indicated. A prescriber can hold a step for four more weeks when a dose is not tolerated, so two people can be on different rungs in the same month. MedlinePlus advises injecting on the same day each week.

   Compounded semaglutide has no FDA-approved label. Your clinician decides your dose and when it changes.

5. 05

   Step 5: Recheck the math when your dose changes

   Every new dose and every new vial means new units. Clinicians make conversion errors too: in FDA reports, one intended 0.25 mg, written as 5 units, and prescribed 25 units, and another prescribed 20 units instead of 2. Run the formula yourself each time and compare it with your written instructions. Here is the Wegovy label ladder at two example concentrations.

Read across any row. Vial A needs twice the units of vial B for the same dose, and 20 units delivers 0.5 mg from vial A but 1 mg from vial B. A unit count means nothing without its concentration.

Most semaglutide dosage errors come from a mismatch between the chart, the vial and the syringe, not from the arithmetic. A summary from the FDA on compounded GLP-1 dosing errors describes patients measuring the wrong amount and, in some cases, health care professionals miscalculating doses.

• Using a chart made for another vial. A table online, a friend's numbers or last month's notes fit only the concentration they were built on.
• Reading units as milligrams. Your semaglutide units are a volume, so 20 units is not 20 mg.
• Moving a decimal point. 0.25 mg and 2.5 mg are ten times apart, the same gap FDA saw when a 2-unit dose was prescribed as 20 units.
• Stepping up faster than prescribed. FDA has reports tied to doses beyond the label, taken more often or raised more quickly. If progress feels slow, read realistic semaglutide results by month and bring it to your clinician rather than changing the dose yourself.
• Keeping a vial too long. FDA recommends discarding a multiple-dose vial 28 days after first use, even with medication left, and using a new needle and syringe for every dose.
• Overlooking an unfamiliar ingredient. FDA says semaglutide sodium and semaglutide acetate are different active ingredients from the one in the approved drugs, so ask before using a vial labeled with either.
• Taking a second dose to fix the first. If you think you drew the wrong amount, do not correct it with another injection.

Arbor's injectable semaglutide ships as a vial you draw from with a syringe, not a prefilled pen, so reading a chart is part of the weekly routine. A board-certified physician reviews your health history and decides whether treatment is appropriate.

Your clinician sets your compounded semaglutide dosage, and your written instructions should give the units for the vial you receive. Arbor includes support from licensed clinicians around the clock, so you can send a question about a new concentration before you draw. Pricing starts at $99 and, per the semaglutide page, stays flat as your dose goes up, though it can vary by plan and offer.

Injectable semaglutide from a compounding pharmacy is not FDA approved, and the FDA does not review compounded drugs for safety, effectiveness or quality before they are marketed. On February 21, 2025, the FDA declared the national semaglutide shortage resolved. Arbor's medication is prepared by licensed U.S. pharmacies.