Semaglutide Unit Conversions: How Many Units Is 2 mg, 1 mL, and Every Dose
Stop guessing your GLP-1 dose. Use these drug-label-matched charts to convert any syringe “unit” mark into milligrams for the most common compounded semaglutide strengths used for weight loss.
On a U-100 insulin syringe, “units” measure volume (1 mL = 100 units); the number of milligrams (mg) of semaglutide delivered depends entirely on the vial’s concentration printed on the pharmacy label. That means 2 mg can equal 80 units from a 2.5 mg/mL vial, 40 units from a 5 mg/mL vial, or just 20 units if your vial is 10 mg/mL. Always do the math-and double-check the label-before you inject.
- A U-100 insulin syringe is calibrated so that 1 unit equals 0.01 mL of liquid.(fda.gov)
- The mg delivered per unit is the vial concentration (mg/mL) × 0.01.
- Compounded semaglutide is commonly dispensed at 2.5, 5, or 10 mg per mL, but specialty pharmacies can make other strengths.
- Most weekly weight-loss regimens start at 0.25 mg (10 U of 2.5 mg/mL) and titrate up to 2.4 mg or more.(accessdata.fda.gov)
- Medication errors happen when the syringe units are correct but the label strength has changed-verify every refill.(fda.gov)
Units on your syringe equal volume, not drug strength
The “unit” marks etched on a U-100 insulin syringe simply divide 1 milliliter into 100 equal parts-each unit is 0.01 mL. They were created for insulin decades ago, but because compounded semaglutide is drawn up with the same syringes, many patients assume a unit equals a fixed amount of semaglutide. It does not. If your vial were filled with plain saline, 50 units would still be just 0.5 mL of saltwater.(fda.gov)
Definition (60 words): Semaglutide units are the volumetric markings on a U-100 insulin syringe, where 1 unit = 0.01 mL of solution; the actual dose in milligrams depends on how many milligrams of semaglutide are dissolved in each milliliter of that solution (its concentration).
Higher vial concentration means fewer units for the same mg
Concentration tells you how much drug is dissolved per milliliter, usually stated as “mg/mL.” A 5 mg/mL vial holds twice as much semaglutide in the same volume compared with a 2.5 mg/mL vial. Therefore, to inject 2 mg:
Example: 2 mg target dose
- 2.5 mg/mL vial → 2 mg ÷ 2.5 mg/mL = 0.8 mL → 80 units
- 5 mg/mL vial → 2 mg ÷ 5 mg/mL = 0.4 mL → 40 units
- 10 mg/mL vial → 2 mg ÷ 10 mg/mL = 0.2 mL → 20 units
One glance at the label tells you which line to follow in the conversion chart below. The U.S. Pharmacopeia sterile-compounding standard USP <797> requires that concentration be stated clearly to reduce mix-ups.(doi.usp.org)
⚠️ Refill surprise
If your pharmacy switches suppliers, your refill may arrive at a different strength. Always compare the mg/mL before drawing up the next dose.
Three-step math to convert units to mg (or mg to units)
You only need one equation: mg = Units × 0.01 mL × (concentration mg/mL).
- Find the concentration on the pharmacy label (e.g., 5 mg/mL).
- Multiply units by 0.01 to get milliliters. Example: 32 units × 0.01 = 0.32 mL.
- Multiply mL by concentration to get milligrams. 0.32 mL × 5 mg/mL = 1.6 mg.
Reverse conversion (mg to units): Units = mg ÷ (concentration mg/mL) ÷ 0.01.
Printable conversion tables for popular compounded strengths
Use the chart that matches your vial strength exactly. Circle your weekly target dose so you (and anyone helping you) can double-check at each injection.
| 2.5 mg/mL Concentration | ||
|---|---|---|
| Units (U-100) | mL Drawn | Semaglutide (mg) |
| 10 U | 0.10 mL | 0.25 mg |
| 20 U | 0.20 mL | 0.50 mg |
| 40 U | 0.40 mL | 1.00 mg |
| 60 U | 0.60 mL | 1.50 mg |
| 80 U | 0.80 mL | 2.00 mg |
| 96 U | 0.96 mL | 2.40 mg |
| 5 mg/mL Concentration | ||
|---|---|---|
| Units | mL Drawn | Semaglutide (mg) |
| 5 U | 0.05 mL | 0.25 mg |
| 10 U | 0.10 mL | 0.50 mg |
| 20 U | 0.20 mL | 1.00 mg |
| 30 U | 0.30 mL | 1.50 mg |
| 40 U | 0.40 mL | 2.00 mg |
| 48 U | 0.48 mL | 2.40 mg |
| 10 mg/mL Concentration | ||
|---|---|---|
| Units | mL Drawn | Semaglutide (mg) |
| 3 U | 0.03 mL | 0.30 mg |
| 5 U | 0.05 mL | 0.50 mg |
| 12 U | 0.12 mL | 1.20 mg |
| 20 U | 0.20 mL | 2.00 mg |
| 24 U | 0.24 mL | 2.40 mg |
| 30 U | 0.30 mL | 3.00 mg |
Want a pen instead of a vial? Check out our custom Ozempic pen dosing guide for fixed-dose options.
Need expert help choosing your GLP-1 dose?
Board-certified weight-loss providers on Rx.com can review your goals and prescribe the exact concentration that fits your budget.
Mistakes to avoid and safe-injection tips
Most dosing errors are concentration errors, not counting mistakes. The FDA specifically warns that switching between different strengths without adjusting units has led to overdoses.(fda.gov)
Label check: Verify the mg/mL every time you open a new vial or get a refill.
Rotate sites: Inject in a different quadrant of the abdomen, thigh, or arm each week to reduce bruising, as recommended in the Ozempic prescribing information.(accessdata.fda.gov)
Use fresh bacteriostatic water: If your pharmacy supplies separate diluent, follow their beyond-use date exactly-see our guide to bacteriostatic water safety.
Store correctly: Compounded semaglutide should stay refrigerated (36–46 °F) and be discarded after 28 days at room temperature.(accessdata.fda.gov)
Never substitute syringes: Only U-100 insulin syringes give you the correct unit calibration for these tables.(fda.gov)
Ready to self-inject compounded semaglutide?
Check the column that fits your situation:
✅ Good to go
- You have a clear prescription with concentration and dosing schedule.
- You own U-100 syringes and alcohol swabs.
- You can identify proper subcutaneous sites.
- You reviewed the conversion table that matches your vial.
- No history of severe hypoglycemia or pancreatitis.
Cost and access: keeping treatment affordable
Compounded vials can cut the out-of-pocket cost of semaglutide by 50–80 percent compared with branded Wegovy or Ozempic pens. Price still varies by concentration because higher-strength solutions use more active ingredient per milliliter.
| Product | Typical Cash Price (30-day) | Cost per 1 mg | Where to buy |
|---|---|---|---|
| Compounded 2.5 mg/mL (10 mL) | $330 | $13.2 | Accredited 503A pharmacy |
| Compounded 5 mg/mL (10 mL) | $550 | $11.0 | Accredited 503A pharmacy |
| Wegovy 2.4 mg pen pack | $1,349 | $56.2 | Retail pharmacy |
| Ozempic 2 mg pen | $939 | $46.9 | Retail pharmacy |
Use Rx.com to compare live prices-most patients pay far less with our free prescription discount card.
🚨 When to Contact Your Healthcare Provider
Contact your doctor immediately if you experience any of the following:
- Severe, persistent stomach pain - could signal pancreatitis.
- Persistent nausea or vomiting - may lead to dehydration.
- Vision changes - report blurred vision promptly.
- Feeling faint or rapid heartbeat - possible severe hypoglycemia if combined with insulin.
- Signs of allergic reaction - rash, swelling of face or throat, or difficulty breathing.
- Sudden mood changes or thoughts of self-harm - call or text 988, the Suicide & Crisis Lifeline, 24/7.
- Pale stools and dark urine - could indicate gallbladder issues.
- Injection-site infection - redness, warmth, or pus at site.
Scientific References
- FDA. Ozempic (semaglutide) Prescribing Information. Updated 2026.
- FDA. Wegovy (semaglutide) Prescribing Information. Updated 2026.
- FDA. Dosing Errors Associated with Compounded Injectable Semaglutide Products. Safety Alert, 2026.
- United States Pharmacopeia. General Chapter <797> Pharmaceutical Compounding-Sterile Preparations. Official Nov 2023.
- FDA. Guidance on 510(k) Submissions for Piston Syringes. Updated 2024.
Frequently Asked Questions
How many units is 0.25 mg of semaglutide?
It depends on concentration. At 2.5 mg/mL, 0.25 mg is 10 units; at 5 mg/mL it is 5 units; and at 10 mg/mL you would draw just 3 units.
10 units of semaglutide is how many mg?
Multiply 10 units × 0.01 mL = 0.1 mL, then multiply by your concentration. That equals 0.25 mg in a 2.5 mg/mL vial, 0.5 mg in a 5 mg/mL vial, or 1 mg in a 10 mg/mL vial.
How many units are in 1 mL of semaglutide?
Exactly 100 units, because the U-100 syringe calibration defines 1 mL as 100 units regardless of drug concentration. The mg content will vary with vial strength.
Can I use a U-40 syringe for compounded semaglutide?
No. U-40 syringes divide 1 mL into 40 units, so the math and the conversion charts in this article will be wrong. Stick with U-100 syringes unless your prescriber gives new instructions.
Is compounded semaglutide FDA-approved?
No. Compounded preparations are not FDA-approved; they are made under section 503A for patients who cannot obtain an approved product. Use an accredited pharmacy and verify the label each time.(usp.org)
Will insurance pay for compounded vials?
Most insurers do not reimburse compounded GLP-1s. However, Rx.com’s price-comparison tool and free discount card can cut cash prices by up to 85 percent.
Where can I buy semaglutide online safely?
See our detailed guide on how to buy semaglutide online, including red flags that signal an unlicensed supplier.
Get Your Semaglutide Dose & Save Today
Licensed U.S. clinicians on Rx.com can evaluate your history, prescribe the exact concentration you need, and ship directly from accredited pharmacies-often for hundreds less than retail.