Vitamin C: does it work, and at what %?

How we grade Vitamin C

We check the disclosed concentration against the effective threshold from peer-reviewed dermatology literature and regulatory monographs, then weigh the formulation and any product-specific study. The grade is computed from the open rubric — re-run it on any ingredient list and you get the same letter. Also labeled as L-Ascorbic Acid, Ascorbic Acid.

The supply of Vitamin C we can actually verify

39 products in our index contain Vitamin C. 22 disclose a concentration we can confirm reaches an effective dose — that's 56%. The rest list it without a number, so its effect can't be verified at any price.

Common questions

What concentration of Vitamin C is effective?

On Visage Theory's rubric, Vitamin C reaches an effective dose at 8% and a strong, research-backed dose at 15%. Below that, the labeled benefit is unlikely no matter how good the marketing is.

Is more Vitamin C always better?

Not necessarily — past the effective range you mostly add irritation risk, not benefit. What matters is clearing the threshold in a stable formula, which is exactly what our grade checks.

How do I know a product actually contains an effective dose of Vitamin C?

Most brands list the active but hide the concentration. When the dose isn't disclosed we can't confirm efficacy, so we withhold a grade rather than guess. Products that disclose an effective dose are graded and listed below.