some forms of anemia are not iron-deficiency but other causes. your doctor may need to do some additional blood tests including one to see if you can bind the iron you are taking (test is called total iron binding capacity). some oral forms of iron are more "absorbable" than others.
why aren't the iron suppliments working for my animea? . i was diagnosed with anemia a while back and been put on a supplement that did't raise my levels. i then tried switching to the easy digest iron and my doctor told me to take at least 3 pills a day. my iron levels are still incredibly low. sometimes i think that it's just coming right out when i urinate because it actually smells like iron and you can sometimes see the little fragments.