Rankings / Immune & Inflammation

Vitamin C (ascorbic acid)

Immune & Inflammation · Essential vitamin / antioxidant

Tier A

Reviewed by Read Off Label · Last reviewed · How we grade

vitaminantioxidantotc
8 / 10
Tier A
Ev 8 Bn 5 Sf 9

Bottom line

Read Off Label grades Vitamin C (ascorbic acid) as A (8.0/10) based on strong evidence, moderate benefit magnitude, and a low-risk safety profile.

Absorption plateaus around 200-400 mg per dose — larger single doses have diminishing returns.

Studied, labeled, or reported-use context: 500-1000 mg/day PO typically; biohacker mega-doses 2-5 g/day split; IV 25-100 g Riordan-style… — OTC (oral); Rx; not individualized guidance.

What the evidence says

Absorption plateaus around 200-400 mg per dose — larger single doses have diminishing returns. IV route bypasses absorption limit for pharmacological levels. Liposomal claims of better absorption have weak data. Hemilä cold meta: ~8% duration reduction with ≥1 g/day chronic supplementation.

Mechanism

Water-soluble antioxidant; required for collagen hydroxylation, catecholamine synthesis, carnitine synthesis; cofactor for Fe and Cu-dependent enzymes; immune cell function requires adequate levels

Studied, labeled, or reported dose & route

500-1000 mg/day PO typically; biohacker mega-doses 2-5 g/day split; IV 25-100 g Riordan-style (off-label)

This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.

Citations

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Common questions

What does the evidence show about Vitamin C (ascorbic acid)'s effects?
Read Off Label rates the evidence for Vitamin C (ascorbic acid) as Strong and the benefit magnitude as moderate, producing an overall grade of A (8.0/10). Absorption plateaus around 200-400 mg per dose — larger single doses have diminishing returns.
What safety findings are reported for Vitamin C (ascorbic acid)?
Vitamin C (ascorbic acid) has a low risk profile in the database. Low (GI upset at >2 g/day; kidney stones in predisposed; hemolysis with G6PD deficiency at extremely high IV doses) Legal status: OTC (oral); Rx (IV high-dose pharmacy compounding).
What doses or routes are reported for Vitamin C (ascorbic acid)?
500-1000 mg/day PO typically; biohacker mega-doses 2-5 g/day split; IV 25-100 g Riordan-style (off-label) This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
How does Vitamin C (ascorbic acid) work?
Water-soluble antioxidant; required for collagen hydroxylation, catecholamine synthesis, carnitine synthesis; cofactor for Fe and Cu-dependent enzymes; immune cell function requires adequate levels

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.