Confused by milligrams, milliliters, and units? You're not alone, this is one of the most common questions we get. Here's a simple breakdown to help you inject the right amount every time.
What's the difference?
Term | What it measures | What it means for you |
mg (milligrams) | The strength/concentration of the vial | This tells you how much medication is packed into the vial. |
ml (milliliters) | The volume of liquid | This is how much liquid you'll draw into the syringe. |
Units | Markings on the syringe | This is what you'll read on your syringe to measure the correct volume. |
Important: Don't confuse mg with units or ml
This is where most people get tripped up. The mg on your vial label (like 4mg or 8mg) refers to the total strength of the medication in that vial, it's not the same as what you'll see on your syringe.
Think of it like coffee:
Imagine you have two cups of coffee, both the same size (same ml), but one is regular strength and one is double strength. If you drink the same amount from each cup, you're getting very different amounts of caffeine.
Your medication works the same way:
A 4mg vial is like regular-strength coffee
An 8mg vial is like double-strength coffee
If you draw 10 units from a 4mg vial, you get a certain dose. But if you draw 10 units from an 8mg vial, you're getting a stronger dose — because the liquid is more concentrated.
Why this matters
Always follow the dosing instructions specific to your vial size. The number of units you inject depends on which vial you have.
Example: Semaglutide dosing comparison
If your doctor prescribes... | From a 4mg vial | From an 8mg vial |
0.25 mg | 12.5 units | 6.25 units |
0.5 mg | 25 units | 12.5 units |
1 mg | 50 units | 25 units |
This is an example to illustrate the concept. Always follow the specific dosing guide provided with your vial or as directed by your doctor.
Notice how the same prescription (mg) requires fewer units from the 8mg vial cause the 8mg vial is more concentrated. Drawing the same number of units from both vials would give you very different doses.
The same dose (in mg) requires different syringe amounts depending on your vial's concentration. This is why it's important to always check which vial you have before injecting.
How units and ml relate
On a standard insulin syringe:
10 units = 0.10 ml
20 units = 0.20 ml
50 units = 0.50 ml
100 units = 1.00 ml
The unit markings on your syringe make it easy to measure small amounts accurately.
Quick tips
Always check which vial you have before drawing your dose
Follow the dosing guide found in your account page specific to your vial size
Don't assume the same units work across different vials, they don't. This is exactly why plan length differs based on your medication.
Still confused?
Reach out to us at [email protected] or message us on Facebook, Instagram, or TikTok @andyou.ph. You can also book a consultation through your account page and our doctors are happy to walk you through your dosing step by step.