Convert between milligrams, micrograms, International Units, and insulin syringe units. Enter a value in any field and see the equivalents instantly — no guesswork, no math mistakes.
The most common source of dosing confusion. Milligrams (mg) and micrograms (mcg) differ by a factor of 1,000. Enter a value in either field to see the conversion.
International Units (IU) are used for certain peptides where biological activity varies by preparation. The conversion factor depends on the specific peptide.
Given your reconstituted solution concentration and desired dose, see exactly how many units to draw on a U-100 insulin syringe. Need help with reconstitution? Use our reconstitution calculator.
Common peptide doses with their equivalents in different units. Syringe units assume a standard reconstitution of 5 mg peptide in 2 mL bacteriostatic water (concentration: 2,500 mcg/mL).
| Peptide | Common Dose | In mcg | In mg | Syringe Units |
|---|---|---|---|---|
| BPC-157 | 250 mcg | 250 | 0.25 | 10 units |
| TB-500 | 2.5 mg | 2,500 | 2.5 | 100 units |
| Ipamorelin | 200 mcg | 200 | 0.2 | 8 units |
| CJC-1295 | 100 mcg | 100 | 0.1 | 4 units |
| GHK-Cu | 200 mcg | 200 | 0.2 | 8 units |
| Semaglutide | 0.5 mg | 500 | 0.5 | 20 units |
| Tirzepatide | 5 mg | 5,000 | 5.0 | 200 units |
| AOD-9604 | 300 mcg | 300 | 0.3 | 12 units |
| DSIP | 100 mcg | 100 | 0.1 | 4 units |
| PT-141 | 1.75 mg | 1,750 | 1.75 | 70 units |
Syringe units based on 5 mg vial reconstituted with 2 mL bacteriostatic water (2,500 mcg/mL, 25 mcg per unit on a U-100 syringe). Your actual units will differ if you use a different vial size or water volume. For safety information, see our peptide side effects and safety guide.
Multiply milligrams by 1,000 to get micrograms. For example, 0.25 mg equals 250 mcg, and 2.5 mg equals 2,500 mcg. This is a standard metric conversion that applies to all peptides.
For human growth hormone (HGH), 1 mg equals approximately 3 IU. So 10 IU of HGH is about 3.33 mg. This conversion factor is specific to HGH — other peptides like BPC-157 and ipamorelin are measured in mcg, not IU.
First determine the concentration of your reconstituted solution in mcg/mL (vial mg × 1,000 ÷ water mL). Then divide your desired dose in mcg by the concentration to get mL. Multiply by 100 to convert to units on a U-100 insulin syringe. For example, 250 mcg from a 5 mg/2 mL solution = 0.10 mL = 10 units.
On a standard U-100 insulin syringe, 100 units equals 1 mL. Each unit is 0.01 mL. A 0.5 mL syringe holds 50 units and a 0.3 mL syringe holds 30 units. The tick marks on the syringe represent units, not milligrams or micrograms of peptide.
1.75 mg equals 1,750 mcg. To convert any milligram value to micrograms, multiply by 1,000 — so 0.25 mg is 250 mcg, 0.5 mg is 500 mcg, 1 mg is 1,000 mcg, and 2.5 mg is 2,500 mcg.
There are 1,000 micrograms (mcg) in 1 milligram (mg). Peptide doses are usually written in mcg while vial sizes are written in mg, so converting between the two is the most common calculation you'll do before drawing a dose.
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