Should You Take Vitamin C Daily with Every-Other-Day Iron Supplements?
Yes, you should take vitamin C daily, including on the days you take iron supplements, as vitamin C significantly enhances iron absorption and the American Gastroenterological Association recommends vitamin C co-administration with oral iron as a Best Practice Advice. 1
Why Daily Vitamin C Makes Sense
The key issue here is understanding that vitamin C works at the moment of iron absorption, not as something that builds up in your system over time. Here's the evidence-based rationale:
Vitamin C's Mechanism of Action
- Vitamin C acts as a powerful enhancer of non-heme iron absorption by forming a chelate with iron that prevents formation of insoluble iron compounds and by reducing ferric to ferrous iron. 1
- This enhancement occurs during the actual absorption process in your gut, meaning vitamin C needs to be present when you take your iron supplement. 1
Optimal Dosing Strategy
- Take 250-500 mg of vitamin C with each iron dose to maximize absorption, as recommended by the American Gastroenterological Association. 1, 2, 3
- On days when you're not taking iron, continuing vitamin C at lower doses (from diet or supplements) is safe and provides general health benefits without risk. 1
The Every-Other-Day Iron Dosing Context
Your every-other-day iron schedule is actually the optimal approach based on recent evidence:
- Iron doses ≥60 mg stimulate an acute increase in hepcidin (a hormone that blocks iron absorption) that persists for 24 hours but subsides by 48 hours. 4
- Alternate-day dosing significantly increases fractional iron absorption compared to daily dosing, making it more effective while reducing side effects. 1, 2, 3, 4
- Taking iron in the morning on an empty stomach with vitamin C maximizes absorption. 1, 3
Practical Implementation
On Iron Days:
- Take your iron supplement in the morning on an empty stomach. 1, 3
- Take 250-500 mg vitamin C simultaneously with the iron. 1, 2, 3
- Avoid coffee, tea, or calcium-containing foods for 1-2 hours. 1, 2
On Non-Iron Days:
- You can continue taking vitamin C at any dose for general health—it won't cause problems. 1
- Vitamin C doesn't accumulate to toxic levels; uptake and storage are strictly limited after high-dose intake. 5
Important Safety Consideration
Critical exception: If you have hemochromatosis or iron overload conditions, you must avoid vitamin C supplements entirely, as vitamin C accelerates iron mobilization and can cause serious cardiac complications. 1 However, this is unlikely if you've been prescribed iron supplements for iron deficiency.
Why Not Just on Iron Days?
While you could theoretically take vitamin C only on iron days, there's no reason to restrict it:
- Vitamin C has no harmful interaction with your body on non-iron days. 5
- The cost and effort of alternating is unnecessary. 1
- Consistent daily vitamin C intake may provide additional health benefits beyond iron absorption. 5
Evidence Quality Note
The recommendation for vitamin C with iron is based on well-established physiological mechanisms and is endorsed as Best Practice Advice by the American Gastroenterological Association. 1 While one randomized trial from 2020 showed equivalence between iron with and without vitamin C, 6 this study used three-times-daily iron dosing (an outdated regimen that increases hepcidin and reduces absorption), making its findings less applicable to your optimal every-other-day schedule. 4
Bottom line: Take 250-500 mg vitamin C with each iron dose, and feel free to continue vitamin C daily on non-iron days without concern.