In some cases, the effects of hydroquinone can be seen in as little as two weeks. However, most should anticipate 8 to 12 weeks of use to see a visible difference depending on a few factors (such as the extent of the hyperpigmentation, how deeply it penetrates, how long it’s been there, etc.).
“As with any product that is applied to the skin, hydroquinone can cause dryness, redness, and burning, which may signal an allergic reaction to the ingredient,” cautions Dr. Cook-Bolden, who always recommends trying a spot test first. Another potential side effect is “ghosting,” which is the inadvertent lightening of the skin outside of the targeted area. To avoid this, apply hydroquinone sparingly to the center of your spot and feather toward the edges.
How to use it: Best applied at night to start, and eventually increased to twice daily for maximum effects. Use it during the day and pair it with sunscreen as the ingredient can cause sun sensitivity.
The well-rated brand Ambi offers hydroquinone-based creams for both normal and oily skin types.
3. Kojic acid
Kojic acid (derived from mushrooms or fermented rice) is commonly used in skin lighteners and is best used in conjunction with hydroquinone for maximum results. “It works by suppressing a key factor in the activity of the pigment cells,” Carlos Charles, M.D., dermatologist and founder of Derma di Colore, tells SELF. “The risk commonly associated with topical kojic acid is allergic dermatitis, and that is why it is primarily found in relatively low concentrations.” Those with sensitive skin should opt for small doses during nighttime only since inflammation and irritation can be side effects. Also, don’t expect speedy results—it can take several months to see improvement of hyperpigmentation with the use of topical kojic acid.
How to use it: At nighttime, only on dark spots or areas of concern.
If you’re curious about kojic acid, give these top-rated serums a try—many of them contain other hyperpigmentation-reducing ingredients like niacinamide, tranexamic acid, and the aforementioned vitamin C.
Soy extract, which is derived from the soybean plant, has been shown to help brighten the skin, Joshua Zeichner, M.D., director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City, tells SELF. That’s why you’ll find it in tons of skin-lightening products. Soy works as a dark spot corrector by preventing melanin from entering the top layer of skin, according to the American Academy of Dermatology (AAD).
How to use it: Apply to dark spots in the morning and at night, before using your usual moisturizer.
This nourishing night cream from Aveeno is a great option not just for treating dark spots but for reducing dullness and blotchiness overall.
5. Azelaic acid
This lesser-known ingredient is a dermatologist-recommended treatment for dark spots on the face. So what is it exactly? “Azelaic acid is a naturally occurring extract from oat, wheat, or rye that interferes with the production of abnormal pigmentation,” Dr. Zeichner explains. Bonus: It has antibacterial properties that can help banish acne and the scars pimples leave behind.