Elemental Iron Content Comparison
No, 30 mg of elemental iron from ferro-bis-glycinate is NOT equivalent to the elemental iron in 300 mg of ferrous sulfide—you appear to be asking about ferrous sulfate, which contains approximately 65 mg of elemental iron per 200 mg tablet, meaning 300 mg would provide roughly 97.5 mg of elemental iron, more than three times the amount in your ferro-bis-glycinate preparation. 1, 2
Understanding the Chemistry
The key issue here is distinguishing between the total compound weight versus the elemental iron content:
- Ferrous sulfate 200 mg contains 65 mg elemental iron (approximately 32.5% elemental iron by weight) 1, 2
- By extrapolation, ferrous sulfate 300 mg would contain approximately 97.5 mg elemental iron
- Your ferro-bis-glycinate preparation explicitly states it contains 30 mg elemental iron 3
Therefore, 300 mg of ferrous sulfate provides more than 3 times the elemental iron (97.5 mg) compared to your ferro-bis-glycinate preparation (30 mg). 1, 2
Important Clarification on "Ferrous Sulfide"
- You mentioned "ferrous sulfide" in your question, but this is likely a confusion with ferrous sulfate, which is the standard iron supplement 1, 4
- Ferrous sulfide is not used as an oral iron supplement in clinical practice
- All guideline references discuss ferrous sulfate, not ferrous sulfide 1, 2
Clinical Dosing Context
For treating iron deficiency anemia, the recommended therapeutic range is:
- 50-100 mg elemental iron once daily is the optimal starting dose 1, 2
- One ferrous sulfate 200 mg tablet daily (providing 65 mg elemental iron) falls within this ideal range 2
- Your 30 mg ferro-bis-glycinate preparation is below the standard therapeutic range but may be appropriate for prophylaxis or mild deficiency 3, 5
Bioavailability Considerations
While ferro-bis-glycinate (iron bis-glycinate chelate) may have enhanced absorption compared to ferrous sulfate, this does not mean 30 mg of elemental iron from bis-glycinate equals 97.5 mg from ferrous sulfate:
- Studies show ferro-bis-glycinate can be 2.5-3.4 times more bioavailable than ferrous sulfate 6
- However, even with maximum bioavailability advantage (3.4×), 30 mg of elemental iron from bis-glycinate would only provide absorption equivalent to approximately 102 mg of ferrous sulfate—still requiring the full 30 mg elemental iron content, not matching 300 mg of the ferrous sulfate compound 6
- Recent evidence shows 25 mg elemental iron as ferrous bisglycinate has fewer GI side effects than 50 mg ferrous sulfate, but both are effective for prophylaxis 5