The gp (nhs) doesnt ever recommend ferrous bisglycinate as on the nhs they only offer what is in BNF; ferrous sulphate, ferrous fumarate and another one, cant remember. They know these are cost effective, and proven to be clinically effective and lets be honest, our "comfort or pain" in taking them isnt on their list of things to consider.
The ferrous bisglycinate im taking is a food supplement, not a medication. So it hasnt been proven or tested in the same way as a drug. I buy it myself from boots , gentle iron. I take 40 mg every other day with vitamin c and plenty of water, sometimes with a clementine too. No tea coffee or other food for 2 hours. There are too many foods interfering with iron absorption.
Only taking every other day because once you take iron hepcidin levels rise for 24 hours and hinder absorption: you increase the amount absorbed by leaving a whole day gap.
Ferrous sulphate and fumarate burn my stomach ,cause me pain and i end up with diarrhoea which affects my ability to take more. I havent had the same issues with ferrous bisglycinate.
I looked all this up. It might help you.
Out of the 65 mg of elemental iron contained in a single 200 mg ferrous sulphate tablet, your body will typically absorb approximately 6.5 mg to 13 mg. 1]
The body absorbs roughly 10% to 20% of the elemental iron from standard oral supplements. The remaining 80% to 90% goes unabsorbed and continues down through your digestive tract, which is what typically triggers common side effects like dark stools or constipation. A similar amount of absorption applies to ferrous fumarate.
While standard ferrous sulphate/fumarate has an absorption efficiency of about 10% to 20%, ferrous bisglycinate has a much higher fractional absorption rate, typically ranging from 30% to 46% in individuals with low iron stores. So from 40 mg of ferrous bisglycinate, you could absorb 12 mg to 18.5 mg of elemental iron.
Gps and even pharmacists ive had involvement with, dont tend to know these figures to be able to give guidance . Its women, who' ve had iron problems for years, that have a vested interest in knowing and learning this.