mg to mcg and IU Converter for Peptides and Hormones
Convert milligrams, micrograms and international units. IU conversions are shown only for substances with a standard factor (human insulin and somatropin).
This calculator checks arithmetic only. It is not medical advice and does not recommend any amount. Research-use products are not intended for human use; follow the prescribing information for any medication.
Why IU needs a substance
A milligram is a mass; an international unit (IU) is a measure of biological activity against a reference standard. Each substance has its own factor, so there is no universal mg-to-IU conversion:
| Substance | Factor |
|---|---|
| Human insulin | 1 mg ≈ 28.8 IU (1 IU ≈ 34.7 mcg) |
| Somatropin (HGH) | 1 mg ≈ 3 IU |
| hCG and most research peptides | No fixed factor; use the unit on the label |
See the mg, mcg and IU guide for worked examples.
FAQ
How many mcg are in 1 mg?
1 mg equals 1,000 mcg. 0.25 mg is 250 mcg.
Can I convert peptide mg to IU?
Only for substances with a standard factor, such as human insulin (about 28.8 IU per mg) and somatropin (about 3 IU per mg). Most research peptides have no IU definition.