Dosing Errors Are Rising as More Americans Self-Inject GLP-1 Drugs

ByBNW Staff

The rise in popularity of GLP-1 medications such as semaglutide and tirzepatide has transformed the way many Americans are managing their weight and type 2 diabetes. However, there is a growing concern over dosing errors when using these medications at home.

While patients can receive pre-measured injection pens, many have been receiving compounded versions of the medication. These are produced in multi-dose vials by pharmacies, often via telehealth services. Dosing errors can occur when the patient takes the medication from the vial using a syringe.

How the shortages changed the market

Due to high demand for semaglutide and tirzepatide, federal regulations permitted licensed pharmacies to create compounded versions of the medication. This was done as both were on the FDA’s shortage list. Telehealth companies capitalized on this.

However, the FDA has now confirmed that both shortages have been resolved. Tirzepatide was removed in late 2024 and semaglutide in early 2025. Compounding pharmacies were then given deadlines to stop mass-producing copies. Even so, compounded and ‘research’ versions are still widely discussed online. Many patients are learning how to dose correctly from the vials.

FDA Warnings

The FDA issued a public notice in 2024 regarding adverse events due to dosing errors when using compounded semaglutide. Some patients had received higher doses of medication than intended. Issues reported include severe nausea, vomiting, abdominal pain, fainting, dehydration and hospital visits.

The issues were often due to:

  • Confusion between units, mg and ml – Often patients would be told to take a certain unit of medication but the syringe was measured differently.
  • Different concentrations – Often when using two vials of the same medication they may not have the same concentration (mg/ml). This means the same measurement on the syringe will mean different doses.
  • U-100 insulin syringes – These are measured in units. This does not mean the actual amount of medication but the volume.
  • Self-mixing – Some medications come as a powder and need to be dissolved before use. This adds another step to the equation.

Confusion with dosage calculations

With branded pens patients simply turn the dial to the correct dosage. With vials the calculation depends on the amount of medication in the vial and the volume of the solution. If either of these are changed, the correct measurement on the syringe will change.

Pharmacists will often advise to check the concentration of the medication (mg/ml) on the label. This should then be matched to your prescription. A peptide calculator can help to understand how the mg, ml and units on the syringe relate. This is just a learning tool, not a substitute for your prescriber’s or pharmacist’s instructions.

Doctor Recommendations

Most clinicians will give similar advice to patients using GLP-1 medications.

  • Write down the dose, including amount of medication and what mark on the syringe.
  • Check the concentration of the medication every time you get a new vial.
  • Use the recommended type of syringe.
  • Ask the pharmacist to show you how to take your first dose.
  • Only increase your dose as prescribed. Many side effects will occur when increasing your dose.
  • Seek rapid treatment if you experience severe or ongoing vomiting, abdominal pain or signs of dehydration.

Research Peptide Market

In addition to compounded prescriptions, there are many online vendors selling GLP-1 and other peptides for ‘research use only’. These aren’t approved for use in humans and there is no assurance on the purity and strength of the product. For readers who want to understand the differences between approved medications, compounded medications and research chemicals, the educational site What are Peptides explains the basics in plain English.

Conclusion

GLP-1 medications are some of the most effective medications ever approved to help with weight management and type 2 diabetes. Using a vial and syringe can cause more errors than using a pre-filled pen. Following clear instructions, checking the concentration carefully and speaking to a pharmacist will help reduce your risk of an unnecessary trip to the emergency room.

This article is for general information only. Please follow the instructions provided by your prescriber and pharmacist for correct dosing.