For hyperpigmentation treatment, which of the following ingredients is effective?

Kojic acid is recognized as an effective ingredient for treating hyperpigmentation. It works by inhibiting the enzyme tyrosinase, which is crucial in the production of melanin, the pigment responsible for skin color. By reducing melanin production, kojic acid can lead to a more even skin tone and diminish the appearance of dark spots associated with hyperpigmentation.

In contrast, while hyaluronic acid is known for its ability to hydrate and plump the skin, it does not specifically target pigmentation issues. Aloe vera is primarily used for its soothing and healing properties rather than for addressing melanin production. Salicylic acid, often used for treating acne, can help with exfoliation and may improve skin texture but does not have a direct effect on reducing hyperpigmentation. Therefore, kojic acid stands out as the most relevant and targeted option for hyperpigmentation treatment.