Editor’s tip: Never used body serum? We’ve got you: “Body serums give your skin below the same love that your face gets. We often neglect our body in terms of skin health, focusing on the favorite child, the face,” board-certified dermatologist Mona Gohara, MD, previously told Allure. “Body serums use actives to address skin concerns, bring out radiance, even out the tone or firm up the limbs and trunk.”
Key ingredients: lactic acid, glycolic acid, mandelic acid, niacinamide | Who it’s for: Anyone with discoloration below the neck | Fragrance-free: yes
Frequently Asked Questions
What is kojic acid, and what does it do?
Kojic acid is a substance derived by funghi—namely, mushrooms, according to Dr. Graf. It’s best known for its skin-brightening properties, since it acts as a tyrosinase inhibitor (which, like we mentioned, interferes with and slows the pigment production process, resulting in less pigment and therefore, more even skin tone). Unlike, say, salicylic acid, its primary function in skin doesn’t involve exfoliation.
“Tyrosinase inhibitors are commonly used in skin care products due to their ability to help with dark spots and uneven skin tone,” says Dr. Woolery-Lloyd. And they work best in groups, which is why you can find kojic acid paired with other tyrosinase inhibitors like vitamin C, licorice extract, and tranexamic acid. (The benefit of vitamin C is that it also functions as an antioxidant, thus neutralizing the free radicals that can lead to more discoloration when left unchecked.)
Since acne scars, sun spots, and hyperpigmentation benefit from a multi-pronged approach, you’ll also find it alongside niacinamide, which works in a different way—by inhibiting the transfer of melanosomes, or bundles of pigment, to skin’s surface, if you want to get nerdy about it—to even out skin tone. As it’s an active ingredient, you can usually find it in face serums and treatments instead of toners and cleansers—as they allow for high concentrations.
What are the potential side effects of kojic acid?
While at the levels found in over-the-counter products, kojic acid is unlikely to have any side effects, it can cause “skin irritation, redness, and dryness, especially with higher concentrations or prolonged use,” says Dr. Graf. For that reason, if you know you have sensitive skin, consider patch-testing it or taking a gradual approach (use it twice a week and work your way up from there).
And, although sunscreen use should be a habit anyway—especially if you’re dealing with discoloration—“it can also increase skin’s sensitivity to sunlight, so I recommend always wearing sun protection during use,” she says.
How long does kojic acid take to work?
While it can vary from person to person, “some may see improvements in skin tone and a reduction of dark spots within four to six weeks of consistent use,” says Dr. Graf. Again, that assumes you’re wearing sunscreen, since sun exposure can undo kojic acid’s hard work. And she does warn that severe hyperpigmentation can take longer to fade—think three months or more.
What should you not use with kojic acid?
When using kojic acid, it’s important to be aware of the ingredients in other formulas you’re using. According to Dobos, skin-care products with a very low pH, like those containing AHAs or BHAs, can lead to increased irritation and dryness when paired with kojic acid.
