Hi I did review your concern. Both iron sulfate and bisglycinate have different amounts of elemental iron and that relates with toxicity and abdominal side effects as well as amount of response that occurs. Higher the elemental iron, higher the toxicity but higher the response. So a balance is required. Iron bisglycinate 50 mg bid is a right dose to start with and the best way to measure response is to get a reticulocyte count at 1week after response. it should rise in response to iron therapy. Also iron bisglycinate has 20% w/w elemental iron in it just like ferrous sulfate. It has more bioavailability and known to cause less Gastrointestinal disturbances as compared to ferrous sulfate. I hope this helps Wish you all the best Thank you for choosing healthcaremagic