Vitamin C
Vitamin C (Ascorbic Acid)
A required nutrient with no direct AGA evidence. Useful only as an iron-absorption cofactor in patients supplementing iron.
How Vitamin C works — and how well we know it
Required cofactor for collagen synthesis and iron absorption. No direct hair growth mechanism documented.
oral
75–90 mg/day (RDA). Mega-doses (1,000+ mg/day) common in supplements without proven hair benefit.
Available as a dietary supplement. RDA 75–90 mg/day. Aids iron absorption.
Improving iron absorption when supplementing for iron-deficiency-related hair loss.
Evidence distribution across 1 claims
Why the grade is F. No direct evidence for hair growth in non-deficient adults. Useful as an iron-absorption aid in patients supplementing iron.
Every claim, traced back to its source
We took every major claim made about Vitamin C and matched it to the specific experimental model behind it. Click a claim to see the model, the finding, and our assessment of how much weight it deserves.
1 claims · evidence-by-evidence breakdown
1Open-LabelWeight: ModerateVitamin C has no documented direct hair-growth effect in non-deficient adultsIncluded for cofactor logic, not for any actual hair-growth evidence.
Absence of RCT or observational evidence in indexed databases.
No peer-reviewed study has demonstrated that vitamin C supplementation in non-deficient adults affects AGA outcomes.
Vitamin C's inclusion in hair supplements is a 'cofactor logic' move (it's needed for collagen and iron absorption, both vaguely connected to hair). The connection doesn't translate into an actual hair-growth claim.
What's still missing from the science
- Direct evidence of any kind.
Our verdict on Vitamin C
Not in our formulary yet
We don't carry this ingredient. We only formulate around actives where the evidence — and the safety profile — is strong enough to recommend with confidence. As the data matures, we may revisit.
Related treatments
How does Vitamin C stack up against its closest peers?
A genuine cause of reversible hair shedding in iron-deficient patients — but useless and potentially harmful if your iron stores are normal.
Read the breakdown →A botanical 5-alpha reductase inhibitor whose only high-quality trials (in BPH) showed no benefit over placebo; the positive AGA data are small and low-quality.
Read the breakdown →One small Malaysian RCT showed a hair-count increase. Never replicated. Used by Nutrafol to justify its tocotrienol content.
Read the breakdown →