Ferulic acid and its derivatives are included in some skincare formulations aimed at addressing age spots (also known as solar lentigines or hyperpigmentation), primarily due to their antioxidant properties. Ferulic acid is a plant-derived phenolic compound that can neutralize free radicals, thus limiting oxidative damage that contributes to skin aging and pigment changes. Some laboratory (in vitro) and animal studies indicate that ferulic acid can inhibit melanin synthesis by interfering with tyrosinase, a key enzyme involved in the production of melanin, the pigment responsible for age spots. There is also evidence that ferulic acid can stabilize other antioxidants, such as vitamins C and E, enhancing their efficacy in skin-brightening and photoprotection.

However, direct clinical evidence in humans for ferulic acid derivatives specifically reducing existing age spots is limited. Most human studies focus on its antioxidant and photoprotective effects, rather than direct depigmentation. Some cosmeceutical products containing ferulic acid combined with other actives (like vitamin C) have shown modest improvements in hyperpigmentation in small clinical trials, but the specific contribution of ferulic acid derivatives is not well isolated.

In summary, while there is a plausible scientific rationale and some preliminary evidence for the use of ferulic acid derivatives in supporting treatment of age spots, the strength of direct clinical evidence is currently weak, justifying a low to moderate rating.