International Unit (IU)
Also known as: IU · units · insulin unit · syringe units
A measure of biological activity; on a research syringe the "units" scale is a convenient volume marker, not a mass.
An International Unit (IU) is a unit of measurement based on a substance’s biological activity rather than its mass — used where the active amount matters more than the weight, historically for hormones and vitamins.
In practical peptide reconstitution, the "units" printed on an insulin-style research syringe (100 units = 1 mL) are used as a fine volume scale. Combined with the concentration set at reconstitution, the unit markings let a precise volume be measured out.
Because IU and the syringe "unit" scale are easy to confuse, a reconstitution calculator is the safest way to translate a target amount into syringe units.
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RELATED TERMS
Reconstitution
The process of dissolving a lyophilised (freeze-dried) peptide in a sterile solvent such as bacteriostatic water before study.
Subcutaneous
Into the layer of fat just beneath the skin — the route most peptide research protocols reference.
Molar Mass
The mass of one mole of a compound (in g/mol or Daltons) — used to convert between milligrams and moles.
Bacteriostatic Water
Sterile water containing 0.9% benzyl alcohol, the standard solvent for reconstituting peptides so a multi-use vial stays sterile.
Educational content, not medical advice. All products supplied for research purposes only — not for human consumption.