| Property | Iron | Vitamin C |
|---|---|---|
| Scientific name | Ferrous sulfate / bisglycinate | Ascorbic acid |
| Safety rating | Conditionally Safe | Generally Safe |
| Evidence level | Strong | Strong |
| Category | Trace Minerals | Water-Soluble Vitamins |
| RDA | 8 mg (M) / 18 mg (F) | 90 mg (M) / 75 mg (F) |
| Tolerable UL | 45 mg | 2,000 mg |
| Clinical pearl | Test ferritin before prescribing — never supplement empirically. Iron is a pro-oxidant; supplementation in replete patients (ferritin >200 ng/mL) increases oxidative stress [1]. Every-other-day dosing matches daily dosing for hemoglobin recovery with superior tolerability and fractional absorption [3]. Ferrous bisglycinate: equivalent efficacy, fewer GI side effects than sulfate. Always co-prescribe vitamin C [1]. | Prophylactic supplementation (200 mg or more per day) reduces cold duration by 8% in adults and 14% in children but does not prevent colds [3]. Bioavailability plateaus above 200 mg per dose — split larger doses [1]. Co-prescribe with iron-rich meals to enhance non-heme iron absorption 2–3 fold [1]. Smokers require an additional 35 mg/day [1]. |
| Key interactions | See profile | See profile |
| US products (DSLD) | 2,238 | 5,317 |