Lactic acid is an alpha hydroxy acid (AHA) that exfoliates surface skin while also helping with hydration. Products containing around 10–12% lactic acid are commonly used for rough skin, although sensitive skin may need a gentler product or less frequent application.

After a lukewarm shower, pat your knees dry and apply a thin layer of the lotion. Once absorbed, follow with a fragrance-free moisturizer or a small amount of petroleum jelly to reduce moisture loss overnight. Avoid applying acids to broken or irritated skin.

Don’t try to speed things up with aggressive scrubbing, lemon juice, baking soda, or other harsh DIY treatments. Irritation can actually make discoloration more noticeable. If your knees are exposed to sunlight, sunscreen can also help prevent pigmentation from becoming darker.

Improvements in dryness and texture may appear sooner than changes in pigmentation, which can take weeks or longer. If the skin becomes thick and velvety, darkens rapidly, or similar changes appear around the neck, underarms, or groin, speak with a healthcare professional because another condition, including acanthosis nigricans, may be involved.