Vitamin C in this tonic serves as an antioxidant and brightening agent. The product description states it helps the complexion look more even and offers added protection against the visible effects of environmental stress (like pollution). This means it can contribute to reducing the appearance of dullness and uneven tone over time with consistent use.
However, since this is a rinse-off cleanser, the vitamin C's contact time with your skin is relatively short compared to a leave-on serum. You'll primarily benefit from its brightening effect during the cleansing process and its antioxidant protection. For more pronounced brightening, consider following with a leave-on vitamin C serum as part of your routine. Remember, this product is a cosmetic for cleansing and improving skin appearance—it's not intended to treat medical skin conditions.