Fergon High Potency Iron Supplement is a trusted source of iron with a strong brand heritage preferred by loyal consumers. The iron in Fergon is in the form of ferrous gluconate and is highly soluble. This means it is easily digested and causes fewer side effects such as upset stomach, bloating, or constipation that can often accompany iron supplements. Fergon's bioavailability means it is highly effective once in your body, replenishing the iron in your blood cells quickly.