Why Low-dose is more efficient than High-dose when it comes to iron.A Heme-Iron tablet with a dose of 18 mg will yield up to 4 mgs for bodily needs, whereas a non-heme tablet of 100 mg will yield 2 mg. The rest is reactive and remains in the gut. The body will absorb no more than it needs of Heme-Iron and the rest is completely inert – no stomach problems.