Best Form of Ferrous Sulfate

Not all forms of Ferrous Sulfate are equal. The form determines how efficiently your body absorbs and uses the nutrient. Lower-quality forms — often found in mass-market supplements — can have dramatically lower bioavailability than premium alternatives.

FormulaForge ranks each form using a 100-point absorption score that combines bioavailability percentage, formulary tier classification, relative multiplier versus the gold-standard form, and our S1–S4 bioavailability tier. T1 Preferred forms represent the best available evidence for absorption efficiency.