Fat Scientist

Help! I can't understand my prescription label. What's my concentration?

Medication labels can look confusing with all their numbers and text, but there's one key piece of information you need: the concentration.

Think of concentration as the strength of your medication. Just like a strong cup of coffee has more caffeine per ounce than weak coffee, a higher concentration medication has more medicine packed into each milliliter of liquid.

What you're looking for: A number followed by either mg/mL or mg/0.5mL (like 10mg/mL or 5mg/0.5mL). Our calculators support both via a unit toggle above the concentration field, so you can enter what you see on the label and we'll convert as needed.

Simple example: If your label says "15mg/mL", that means:

  • Every 1mL (which equals 100 units on your syringe) contains 15mg of medicine
  • So for a 15mg dose, you'd inject exactly 1mL (100 units)
  • For a 7.5mg dose, you'd inject 0.5mL (50 units)

The examples below show you exactly where to find this concentration number on different types of labels.

Standard Format

Most common format showing concentration as X mg/mL:

COMPOUNDED MEDICATION
Tirzepatide 20 mg/mL
For subcutaneous injection only
Qty: 5mL       Rx#: 12345
Exp: 03/24/2025
Store refrigerated (2-8°C/36-46°F)

In this format, the concentration is clearly stated as mg per mL. This is the easiest format to read as no calculation is needed.

The concentration is 20 mg/mL, so you would enter "20" in the calculator.

Partial mL Format (mg/0.5mL)

Sometimes pharmacies list concentration per 0.5mL instead of per full mL. You can now use the unit toggle to select mg/0.5mL and enter the number exactly as shown on your label.

COMPOUNDED MEDICATION
Semaglutide 2mg/0.5mL
Total Volume: 2.5mL
For subcutaneous injection only
Rx#: 67890       Lot#: TZ0224A
Exp: 04/15/2026
Keep Refrigerated

Easy mode: Select mg/0.5mL in the calculator and enter the number from your label. We'll convert to mg/mL automatically.

Manual conversion (optional):

  • Label shows: 2mg/0.5mL
  • Since 0.5mL = half of 1mL, double the mg value
  • 2mg × 2 = 4mg → 4mg/mL
Best practice: Use the mg/0.5mL toggle and enter "2" to avoid mistakes — the calculator will show both mg/mL and mg/0.5mL in results.

Format with Additives

Many pharmacies add extra ingredients like B12, niacinamide, or glycine:

COMPOUNDED MEDICATION
Tirzepatide/Niacinamide
8/2 mg/mL
Volume: 5mL       Rx#: 13579
Exp: 11/30/2026   Lot#: TZN0224B
Store in refrigerator
Discard after: 28 days from first use

Key rule: Only the tirzepatide or semaglutide concentration matters for dosing. Ignore all the other ingredients and their numbers.

How to find the right number:

  • Look for "Tirzepatide" or "Semaglutide" in the ingredient list
  • Find which position it's in (first, second, etc.)
  • Use the concentration number in that same position
  • In this example: Tirzepatide is listed first, so use the first number (8 mg/mL)
The tirzepatide concentration is 8 mg/mL, so you would enter "8" in the calculator.
(Ignore the niacinamide and its concentration—it doesn't affect your dosing)

Want to Learn More?

This is just a quick overview of reading medication labels. Get the complete guide with more examples, common pitfalls, and detailed explanations, or test your understanding with our interactive quiz.