Quick answer
Iron bisglycinate is generally gentler on the stomach than ferrous sulfate because it is chelated, which means the iron is bound to glycine for better absorption and less GI irritation. If you have a sensitive stomach, iron bisglycinate is often the better choice.
Why iron bisglycinate is gentler
Iron bisglycinate is a chelated form of iron, meaning the iron is attached to the amino acid glycine. This chelation allows the iron to be absorbed more efficiently and reduces the amount of unabsorbed iron that can irritate the digestive tract. As a result, it is less likely to cause nausea, constipation, or stomach cramps compared to ferrous sulfate.
Ferrous sulfate is an older, more traditional iron supplement. It delivers a high amount of elemental iron per dose, but it is not chelated, so more iron remains unabsorbed in the gut, which can lead to the classic GI side effects. If you have experienced stomach upset with iron supplements before, switching to iron bisglycinate may help.
Absorption differences you should know
Iron absorption is influenced by the form of iron and how it is taken. Iron bisglycinate is absorbed differently than ferrous sulfate because it uses a separate transport pathway, which means it is less affected by other foods and supplements that can inhibit iron absorption, such as calcium or phytates.
Ferrous sulfate is best absorbed on an empty stomach, but that often increases the risk of GI upset. Iron bisglycinate can be taken with or without food, which makes it more flexible and easier on the stomach. This is a key reason why many people find iron bisglycinate easier to tolerate.
Who should consider other iron forms
While iron bisglycinate is gentle, it is not the only option. Ferrous sulfate is often less expensive and may be preferred by those who do not have stomach issues and want a high-dose, cost-effective supplement. However, the higher risk of side effects is a real trade-off.
Other forms like ferric citrate or iron polysaccharide complex exist, but they are less common and may have lower absorption rates. If you have a specific medical condition, always consult a healthcare provider before choosing an iron supplement.
Trade-offs at a glance
- Iron bisglycinate: Chelated, gentle on the stomach, can be taken with or without food, fewer GI side effects.
- Ferrous sulfate: Higher elemental iron per dose, often cheaper, but more likely to cause nausea and constipation.
- Your choice: If you have a sensitive stomach or have had side effects before, choose iron bisglycinate. If cost is your main concern and you tolerate ferrous sulfate well, it may be acceptable. Always check with a healthcare provider before starting any new supplement, especially if you have a medical condition.
Product facts
-
Iron Bisglycinate: Gentle chelated iron formula, 1 capsule per serving, vegan, non-GMO. The chelated form is designed to be easier on the stomach, making it a good choice for sensitive individuals.
Iron Bisglycinate
Who should choose what
Best for
- People with a sensitive stomach or a history of GI side effects from iron supplements.
- Those who prefer a vegan, non-GMO supplement with a gentle formula.
Not for
- Individuals who need the highest possible elemental iron per dose and can tolerate ferrous sulfate without side effects.
- Those on a very tight budget who are not bothered by potential stomach upset.