growth is measured in iu's and u usually have to make it yourself. say u have a 20iu bottle, and an insulin syringe that is 100units(1 cc). u put 2 cc's in the bottle, now the insulin syringe also has markings of 10, 20 , 30 ...100. now that makes the 10 unit mark 1 iu. it is easier for insulin, each mark equals one unit, so that is self explainitory. hope i helped clear some things up.