Vitamin
Vitamin C
Vitamin C requires 75 mg daily for adult women and 90 mg for men. The tolerable upper intake level is 2000 mg. It works best alongside Iron bisglycinate and Collagen peptides.
What Vitamin C does
Water-soluble antioxidant and cofactor for collagen synthesis; sharply increases non-heme iron absorption.
Smokers need an extra 35 mg/day. Doses above 400 mg offer little additional absorption.
How much you need
| Measure | Adult male | Adult female |
|---|---|---|
| Recommended intake | 90 mg | 75 mg |
| Upper intake level | 2000 mg | |
| Typical supplement dose | 500-1000 mg | |
Interactions involving Vitamin C
5 sourced rules| Pair | Severity | Mechanism | Action |
|---|---|---|---|
| Vitamin C × Warfarin | Mild | Very high vitamin C doses can reduce warfarin’s effect and have been reported to interfere with INR stability. | Keep vitamin C under 1000 mg per day while on warfarin and keep the dose consistent.Source |
| Iron bisglycinate × Vitamin C | Synergy | Ascorbic acid reduces ferric iron to the ferrous form and chelates it, which can multiply non-heme iron absorption several-fold. | Take 100-500 mg vitamin C with your iron dose. This is the single most effective pairing for iron.Source |
| Vitamin C × Collagen peptides | Synergy | Vitamin C is an obligatory cofactor for prolyl and lysyl hydroxylase, the enzymes that cross-link collagen. Without it, collagen synthesis stalls regardless of peptide supply. | Take collagen with vitamin C — 50 mg or more is enough, though 500 mg is commonly used.Source |
| Vitamin C × Glutathione | Synergy | Vitamin C helps maintain glutathione in its reduced form and spares it during oxidative stress; oral glutathione absorption is also improved by vitamin C. | Pair supplemental glutathione or NAC with vitamin C.Source |
| NAC (N-acetylcysteine) × Vitamin C | Synergy | NAC supplies cysteine for glutathione synthesis, while vitamin C supports the enzyme systems that keep glutathione reduced. | Take NAC with vitamin C, ideally away from a protein-heavy meal.Source |