This form is more gentle on the stomach compared to the more common ferrous fumarate which can cause nausea, vomiting, constipation and diarrhoea. Iron Bisglycinate. (from 70mg Iron Bisglycinate). Bulking Agents (Micro Crystalline Cellulose, Di Calcium Phosphate),Iron Bisglycinate, Anti Caking Agents (Magnesium Stearate, Silicon Dioxide).