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Kojic acid vs vitamin C for the look of dark spots
Both ingredients turn up in “brightening” products, often in the same one. They work in different ways,
so the useful question isn’t which one wins but what each does and how to use them sensibly.
Kojic acid in brief
Kojic acid is made by certain fungi during fermentation (it was first found in the production of sake and
soy sauce). In cosmetics it is used to help even out the look of skin tone. A 2019 review describes how it
interferes with tyrosinase, the enzyme skin uses to make pigment, and notes that its stability in formulas
is a known challenge, which is why it often appears alongside antioxidants or as a derivative (Saeedi et
al., 2019).
It is best known in wash-off products and low-concentration leave-ons. It can irritate some people, so
wash-off formats and two or three uses a week are a sensible start.
Vitamin C in brief
Vitamin C (ascorbic acid and its derivatives) is an antioxidant. On skin it helps neutralize free radicals
from UV and pollution, and it also interferes with pigment production. Reviews of the clinical literature
describe improvements in the look of uneven tone and photoaging with regular use, while pointing out that
results depend heavily on the form, the concentration and how well the formula is protected from light and
air (Telang, 2013; Al-Niaimi and Chiang, 2017).
How they compare
| Kojic acid | Vitamin C | |
|---|---|---|
| Main job | Evening the look of skin tone | Antioxidant, plus evening tone and a brighter look |
| Best format | Wash-off or low-strength leave-on | Leave-on serum in the morning |
| Watch out for | Irritation in sensitive skin | Stability: buy opaque, airtight packaging |
| Frequency | 2–3 times a week to start | Daily |
Using them together
They don’t cancel each other out. A simple way to combine them:
- Morning: vitamin C serum, moisturizer, sunscreen.
- Two or three evenings a week: a kojic acid exfoliator in the shower, then moisturizer.
Our Brightening Face & Body Exfoliator with Kojic Acid
is a wash-off format with vitamin C and vitamin E, and our Vitamin C Serum
covers the morning step.
The part that matters most
No brightening ingredient keeps up with daily sun exposure. UV is what darkens existing spots and triggers
new ones, so broad-spectrum sunscreen every morning does more for an even-looking tone than any serum.
Expect changes over weeks to months, not days. If a spot changes shape, color or size, or bleeds, see a
doctor rather than treating it as a cosmetic concern.
Sources
- Saeedi M, Eslamifar M, Khezri K. Kojic acid applications in cosmetic and pharmaceutical preparations.
Biomed Pharmacother. 2019;110:582–593. - Telang PS. Vitamin C in dermatology. Indian Dermatol Online J. 2013;4(2):143–146.
- Al-Niaimi F, Chiang NYZ. Topical vitamin C and the skin: mechanisms of action and clinical applications.
J Clin Aesthet Dermatol. 2017;10(7):14–17.
Cosmetic information, not medical advice. Patch test new products.