Formulating With Kojic Acid

This is an advanced formula that utilises high end ingredients: Kojic acid, Ascorbyl Palmitate, Ferulic Acid, and Vitamin E, for a real power-packed product.

Heated water phase

0.5% ferulic acid

66.5% deionised water, heated

Heated oil phase

20% oil of choice

4% Olivem 1000

0.5% lecithin

1% ascorbyl palmitate

0.5% Vitamin E

Cool down phase

1% kojic acid

3% deionised water

1% Geogard 221

Three beakers

Spatula or silicone spatula

Immersion/stick blender

Thermometer

pH strips or digital pH meter

In one beaker, weigh out the deionised water and ferulic acid. It won't completely dissolve so don't worry if there is some residue at the bottom.

In another beaker, weigh out and melt the oil phase ingredients.

In the last beaker, prep the kojic acid solution by mixing the kojic acid with the deionised water.

Make sure the heated water phase and heated oil phase ingredients are both at about 75-80 degrees. Add the oil phase into the water phase and blend with high shear until emulsified. Then stir while cooling down.

Once the emulsion has cooled to below 40 degrees, add in the kojic acid solution and the preservative. Give it a short burst with the blender to fully combine.

Check the pH and adjust if required (mine didn't need any adjusting).

Decant into a dark glass pump bottle to prevent light and oxygen getting in.

Please use sunscreen when using products containing kojic acid.

Kojic Acid FAQ

What does kojic acid do in skincare?

Kojic acid helps reduce the appearance of dark marks and uneven skin tone by inhibiting tyrosinase, an enzyme involved in melanin production. By slowing excess melanin formation, it supports a more even-looking complexion over time.

What is the maximum safe concentration of kojic acid?

In cosmetic formulations, EU regulations limit kojic acid to a maximum of 1% in leave-on products. This limit applies to finished cosmetic products intended for topical use. Higher concentrations are not permitted in leave-on cosmetics and are not recommended for home formulation.

What pH is kojic acid most stable at?

Kojic acid is most stable in an acidic environment, typically within a pH range of 3.5–4.5. It becomes unstable in alkaline conditions, which can lead to degradation and reduced effectiveness.

Why does kojic acid need dark packaging?

Once activated, kojic acid is sensitive to light, heat, and oxygen. Dark or amber packaging helps limit light exposure and slows oxidative degradation, improving both stability and shelf life of the finished product.

Can kojic acid be used daily?

Kojic acid can be used daily at low, regulated concentrations, but tolerance varies by individual. Some skin types may prefer less frequent use, especially if sensitivity occurs. As with most brightening actives, consistent but gentle use tends to give better results than aggressive application.

Is sunscreen necessary when using kojic acid?

Yes. Daily sunscreen use is recommended when using products containing kojic acid. While kojic acid itself is not an exfoliating acid, improving pigmentation concerns requires protecting skin from UV exposure, which can otherwise counteract brightening efforts.