AAARGH!
rant coming, heads up.
okay. the IU is the most retarded unit ever invented. it is not a unit of mass, like mg/mcg/grams. it is not a unit of volume, like liters/ml/cc. it is a unit of "potency". this means the number of mg's per IU varies by compound. for insulin, it's 2.6iu/mg. for GH, it's 3iu/mg. every compound that is measured in IU's has its own retarded-ass defined ratio.
there is no defined conversion from mg to iu for igf-i.
we can't even talk about iu's of igf-i. the reason slin pins are marked in iu's rather than something intelligent like ml's is that they are made for the highly standardized insulin manufacture system. all insulin is 100iu/ml, or ~38.4mg/ml. each "IU" on a slin pin is .01ml. it works out there.
it really doesn't work for anything else. think of these as .01ml's, or "ticks" if you want a word, but a tick doesn't always equal a line on a syringe, as neuromancer mentioned. they are not IU's. the syringe is lying. note this also means you can't use those IU's to measure out your IU's of GH because not only are there more IU's per mg, but the concentration of your gh depends on your kit.
MR-brand lr3igf-i comes prediluted at 1000mcg/ml, or 10 mcg/.01ml. every "iu"(but remember, they're trying to **** you up), or .01ml, is 10 mcg.
if you use 2ml of diluent instead, you'll have 500mcg/ml, or 5mcg/.01ml. every "iu", or .01ml, is 5 mcg.