It seems strange to have the measuring unit for something be a “unit” instead of a measurement of mass. There is an agreed upon standard for what a milligram or a microgram is. Outside of the context of insulin, a “unit” is undefined and variable. Context: I’m an RN with type 1 diabetes. I understand drug concentrations and insulin dosing. This one just seems like a strange anomaly in the world of measuring medications. My only guess is that the actual hormone is so minuscule to measure that even nanograms and picograms can’t do it?