Injection Guide

How To Prepare And Inject GLP-1 Medications: Step-By-Step Guide

The most important part of a GLP-1 injection is drawing the right amount for your vial's concentration. Technique matters too, but a correct dose comes first.

Semaglutide and tirzepatide are usually injected once a week, on the same day each week. Liraglutide is injected once a day. Always follow the schedule your healthcare provider prescribed.

If your GLP-1 medication comes in a multi-dose vial, you draw your dose into a syringe before each injection. Your provider or pharmacy should show you how to measure your specific dose before your first injection. This guide walks through each step so you know what to expect.

What You NeedBefore Your Injection

Set everything out on a clean, dry surface before you start.

  • Your GLP-1 medication vial
  • A new, sterile U-100 insulin syringe with needle. A 0.3 mL (30-unit) syringe with half-unit markings is easiest to read for small doses.
  • Alcohol swabs
  • Gauze or a clean cotton ball
  • A sharps disposal container

Keep the vial and supplies away from children and pets. Wash your hands with soap and water, then dry them with a clean towel.

Ongo Weight Loss injection supplies, including the complete guide, GLP-1 multidose vial, syringe, alcohol swabs, cotton, and a sharps disposal container

Step 1: Check Your GLP-1 Medication Vial

Take a moment to inspect the vial before you prepare your injection.

Check the label. Confirm that:

  • Your name is on the prescription, if applicable.
  • The medication is the one you were prescribed (semaglutide, tirzepatide or liraglutide).
  • The concentration (mg/mL) matches your prescription instructions.
  • The expiration or beyond-use date has not passed.
  • The vial has been stored as the pharmacy instructed.

Check the liquid. Do not use the vial if you notice:

  • Particles or unexpected discoloration
  • Cloudiness when your instructions say the solution should be clear
  • A cracked or damaged vial, or any leakage

Different formulations can look different, so compare against the instructions for your specific medication. If you think the vial was stored incorrectly, contact your provider or pharmacy before using it.

Compounded semaglutide multiple dose vial labeled 0.5 mL
Diagram from a 0.5 mL semaglutide vial to a 0.20 mg dose, 0.04 mL volume, and 4 syringe units

Step 2: Know Your Prescribed Dose

Confirm exactly how much medication you have been prescribed before you pick up the syringe. Your prescription gives a dose in milligrams (mg), but you measure volume on the syringe. Dose and volume are not the same thing.

For example, a prescription of 0.20 mg semaglutide once weekly does not mean 20 units on your syringe. The amount you draw depends on the concentration of your vial.

The 0.5 mL vial from the Ongo Weight Loss Program contains 5 mg/mL of semaglutide. To get 0.20 mg, you draw 0.04 mL (0.20 mg ÷ 5 mg/mL). On a U-100 insulin syringe, 0.04 mL equals 4 units.

This conversion applies only to that concentration and a U-100 syringe. Always use the dosing instructions supplied with your medication.

Step 3: Prepare The Vial

  1. Take the vial out of storage as your pharmacy instructed.
  2. Inspect the liquid again. Do not shake the vial.
  3. Wipe the rubber stopper with an alcohol swab and let it air-dry.
  4. Do not touch the stopper after cleaning it.

Step 4: Prepare The Syringe

  1. Take a new, sterile syringe out of its packaging.
  2. Pull the plunger back to draw in air equal to the volume of your dose.

For example, if your dose is 0.04 mL (4 units), draw 4 units of air. Pushing this air into the vial makes the medication easier to withdraw.

Step 5: Draw Up Your GLP-1 Medication

  1. Remove the needle cap without touching the needle.
  2. With the vial standing upright, insert the needle through the center of the rubber stopper.
  3. Push the air into the vial.
  4. Turn the vial and syringe upside down together. Keep the needle tip below the liquid level.
  5. Pull the plunger back slowly until it reaches your dose.
Push air into an upright vial, then turn it upside down and draw the dose

Reading A 1 ML (100-Unit) U-100 Syringe

Labeled U-100 syringe showing the needle, rubber stopper, unit markings, plunger, and a 0.20 mg semaglutide example that equals 4 units

How To Read The Syringe Correctly

On a U-100 insulin syringe, 100 units correspond to 1 mL. A 30-unit U-100 syringe has a maximum capacity of 0.3 mL, but the size of its smallest markings varies by model.

When reading the syringe, align the edge of the black rubber stopper closest to the needle with the prescribed marking. Do not assume that every small tick represents half a unit; check the graduations on your particular syringe.

For the example above, the prescribed volume is 0.04 mL, equivalent to 4 units on a U-100 syringe. Use this marking only if your prescription, vial concentration, and pharmacy instructions match the example.

Check For Air Bubbles

Inspect the syringe for air bubbles and follow your pharmacy's instructions for removing them. If you are unsure how to remove a bubble without changing the dose, ask your pharmacist or healthcare provider for guidance.

Never increase or change your prescribed dose to compensate for an air bubble.

Once the medication is drawn up, verify the measurement against your prescribed instructions before proceeding. Use the prepared syringe promptly as directed, and follow the supplied instructions for safe needle handling and disposal. Never reuse a syringe or needle.

Front and back views showing injection sites on the abdomen, front of the thigh, and back of the upper arm

Step 6: Choose An Injection Site

GLP-1 medication is injected subcutaneously, into the fatty tissue just under the skin.

Common injection sites:

  • Abdomen, staying about 2 inches (5 cm) away from the belly button
  • Front of the thigh
  • Back of the upper arm, if your provider advises it. This spot can be hard to reach on your own.

Rotate sites from week to week. Within the same area, keep each injection at least 1 inch (2.5 cm) from the last one. Do not inject into skin that is bruised, red, swollen, tender, scarred, irritated or hardened. Do not inject through clothing.

Step 7: Clean The Injection Site

  1. Wipe the site with an alcohol swab.
  2. Let the skin dry completely before injecting.
  3. Do not touch the cleaned area.

Step 8: Inject Your GLP-1 Medication

Most adults using a short insulin syringe insert the needle straight in, at a 90° angle. If you are very lean, your provider may ask you to pinch the skin or use a 45° angle.

  1. If you recapped the needle, remove the cap now.
  2. Pinch a fold of skin if your provider has told you to.
  3. Insert the needle into the skin at the angle recommended for your syringe.
  4. Push the plunger slowly and steadily until the full dose is delivered.
  5. Keep the needle in place for 5 to 10 seconds so the medication does not leak out.
  6. Pull the needle straight out.

If there is a small amount of bleeding, press gently with gauze or a cotton ball. Do not rub the site.

Subcutaneous injection at 90 degrees into the fatty tissue, held in place for 5 to 10 seconds

Step 9: Dispose Of The Syringe Safely

Use a new needle and syringe every time, and never reuse or share them.

  • Put the used syringe and needle straight into an FDA-cleared sharps container.
  • No sharps container? Use a heavy-duty plastic household container with a tight lid, such as a laundry detergent bottle, and label it "Sharps."
  • Never put loose needles in household trash or recycling.
  • Follow your local rules or your pharmacy's advice for getting rid of a full container.

After each injection, note the date, the number of units and the site you used. This helps you rotate sites and keep a steady schedule.

What If You Are Not Sure How Many Units To Inject?

Stop and check before injecting. This matters most with compounded GLP-1 medications, because two vials can hold different amounts of medication per mL. The same dose can then need different syringe volumes.

Do not work out your dose from an online example alone. Check that these four things match:

  • The concentration printed on your vial
  • Your prescribed dose
  • Your syringe type (U-100)
  • The dosing instructions from your pharmacy or provider

If they do not clearly match, contact your provider or dispensing pharmacy before injecting.

How To Store GLP-1 Medication

Follow the storage instructions supplied with your specific medication. Most compounded vials are kept in the refrigerator at 36–46°F (2–8°C), but your pharmacy's instructions come first.

  • Keep the vial in its original container when possible.
  • Keep it away from heat and direct light.
  • Keep it away from children and pets.
  • Do not freeze it.

If the medication has been frozen, exposed to the wrong temperature or stored differently from the instructions, contact your pharmacy before using it.

Common Mistakes To Avoid

  1. Confusing mg with mL. mg is the amount of medication. mL is the volume of liquid. The concentration connects the two.
  2. Treating syringe units as milligrams. Units measure volume on a U-100 syringe (100 units = 1 mL). They do not tell you the mg dose on their own.
  3. Using someone else's instructions. Your dose is specific to you. Never copy another person's unit count.
  4. Reusing needles. Use a new sterile needle and syringe for every injection.
  5. Injecting into irritated skin. Choose healthy skin and rotate sites.
  6. Guessing. If the concentration, dose or syringe markings are unclear, contact your provider or pharmacy.

What If You Miss A Dose?

Missed-dose rules depend on the medication and how long it has been since your scheduled day. Check your medication's instructions or ask your provider or pharmacist.

Do not double your next dose to make up for a missed one.

Possible Side Effects

The most common side effects are nausea, vomiting, diarrhea, constipation, reduced appetite and mild redness or itching at the injection site. These are often strongest after starting or increasing a dose. Eating smaller meals and drinking enough fluids can help.

Tell your provider if side effects are severe or do not ease. Also tell them if you take insulin or a sulfonylurea, since GLP-1 medications can raise the risk of low blood sugar with these.

Who Should Not Use GLP-1 Medication

Semaglutide and tirzepatide carry an FDA boxed warning about thyroid C-cell tumors. Do not use them if you or a family member has had medullary thyroid cancer, or if you have multiple endocrine neoplasia type 2 (MEN 2).

Tell your provider if you are pregnant, planning a pregnancy or breastfeeding. Also tell them about any history of pancreatitis, gallbladder disease or kidney problems.

Compounded GLP-1 medications are prepared by licensed pharmacies and are not FDA-approved. See eligibility criteria

When To Contact Your Healthcare Provider

Contact your provider if you have concerning symptoms after an injection, or if you are unsure about your dose or technique.

Get urgent medical help for:

  • Difficulty breathing, or swelling of the face, lips or throat
  • Severe or persistent stomach pain, with or without vomiting (a possible sign of pancreatitis)
  • Pain in the upper right abdomen, fever or yellowing of the skin or eyes
  • Fainting, or signs of very low blood sugar such as shaking, sweating or confusion

One Thing To Remember

The most important part of a GLP-1 injection is drawing the right amount for your vial's concentration and your prescribed dose.

If you are ever unsure whether to inject 4 units, 10 units, 20 units or another amount, stop. Confirm the calculation with your provider or dispensing pharmacy before injecting.

References

1. Dose Measurement And Syringe Safety

  1. U.S. Food and Drug Administration (FDA). FDA Alerts Health Care Providers, Compounders and Patients of Dosing Errors Associated With Compounded Injectable Semaglutide Products.

    https://www.fda.gov/drugs/human-drug-compounding/fda-alerts-health-care-providers-compounders-and-patients-dosing-errors-associated-compounded

  2. U.S. Food and Drug Administration (FDA). FDA's Concerns With Unapproved GLP-1 Drugs Used for Weight Loss.

    https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss

2. Safe Injection Practices And Vial Preparation

  1. Centers for Disease Control and Prevention (CDC). Safe Injection Practices and Your Health.

    https://www.cdc.gov/injection-safety/about/

  2. Centers for Disease Control and Prevention (CDC). Preventing Unsafe Injection Practices.

    https://www.cdc.gov/injection-safety/hcp/clinical-safety/index.html

  3. Centers for Disease Control and Prevention (CDC). Injection Safety Checklist.

    https://www.cdc.gov/injection-safety/media/pdfs/Safe-Injection-Checklist-P.pdf

3. Official Medication Instructions

  1. U.S. Food and Drug Administration (FDA). Wegovy (semaglutide) Prescribing Information.

    https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/218316s007lbl.pdf

  2. Eli Lilly and Company. Zepbound (tirzepatide): Dosing, How to Use and How to Inject.

    https://zepbound.lilly.com/weight/how-to-use

  3. Eli Lilly and Company. Zepbound (tirzepatide) Instructions for Use.

    https://pi.lilly.com/us/zepbound-pen-us-ifu.pdf

4. Sharps Disposal And Needle Safety

  1. U.S. Food and Drug Administration (FDA). Do's and Don'ts of Proper Sharps Disposal.

    https://www.fda.gov/medical-devices/safely-using-sharps-needles-and-syringes-home-work-and-travel/dos-and-donts-proper-sharps-disposal

  2. U.S. Food and Drug Administration (FDA). Sharps Disposal Containers.

    https://www.fda.gov/medical-devices/safely-using-sharps-needles-and-syringes-home-work-and-travel/sharps-disposal-containers

5. Compounded Medication Safety

  1. U.S. Food and Drug Administration (FDA). Understanding the Risks of Compounded Drugs.

    https://www.fda.gov/drugs/human-drug-compounding/understanding-risks-compounded-drugs

  2. U.S. Food and Drug Administration (FDA). Compounding and the FDA: Questions and Answers.

    https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers

MEDICAL DISCLAIMER - This guide is for educational purposes and does not replace the prescribing information supplied with your medication or individualized instructions from your healthcare provider or dispensing pharmacist. Dosing, preparation, injection technique, storage, and disposal instructions can vary by medication and formulation. Compounded medications may have different concentrations and are not FDA-approved. Always verify your prescribed dose and the correct syringe measurement before injecting.