Safety
Common GLP-1 dosing errors and how to avoid them
The most common GLP-1 dosing errors are confusing 'units' with milligrams, assuming a new vial's concentration matches the last one, and reusing someo
The most common GLP-1 dosing errors are confusing 'units' with milligrams, assuming a new vial's concentration matches the last one, and reusing someone else's dosing instructions. Each can cause a large accidental over- or under-dose. Working in milligrams and confirming concentration prevents most of them.
What you need to know
Error one is the units/milligrams mix-up: an insulin-syringe 'unit' measures volume, and the milligrams it contains depend on concentration. Reading a dose in units without knowing mg/mL is the single most common — and most dangerous — mistake with compounded injectables.
Error two is the concentration-change trap: compounded refills can arrive at a different concentration than before, so the same syringe mark now delivers a different dose. People who don't re-check assume continuity that isn't there.
Error three is borrowed instructions: copying a dose a friend or forum uses, or one from a prior product, onto a new vial. Because concentration and ingredient vary, borrowed 'units' are meaningless and occasionally hazardous.
| Error | Why it happens | Prevention |
|---|---|---|
| Units ≠ mg | Units measure volume, not drug | Always dose in mg; get mg/mL from pharmacy |
| Concentration change | Refill differs from last vial | Re-check mg/mL every refill |
| Borrowed dosing | Copying others' 'units' | Never reuse another product's units |
| Wrong syringe | U-100 vs other markings | Use the syringe the pharmacy specifies |
- The concentration (mg/mL) on this specific vial
- Your prescribed dose expressed in milligrams
- That the syringe type matches the instructions
- That the product/ingredient is the same as before
What the evidence shows
- This guidance reflects FDA compounding information, USP standards, and state board of pharmacy resources.
- Verification steps here are public and checkable.
What the evidence does not show
- That following these steps makes a compounded product FDA-approved — it does not.
- That this page replaces personalized medical or pharmacist advice.
Frequently asked questions
What's the most common GLP-1 dosing error?
Confusing units with milligrams — units are volume, mg depend on concentration.
Can concentration change between refills?
Yes, for compounded products. Re-check mg/mL every time.
Related: pharmacy verification hub · safety hub · cost calculator. Compounded medications are not FDA approved.
Not medical advice. This page is consumer education, not medical advice, and does not recommend a dose, product, or provider. Compounded medications are not FDA approved. Talk with a licensed clinician about your situation.