Vitamin A in the form of retinoids (such as retinol and its esters like retinol acetate) is widely used in dermatology for the treatment of various skin conditions, including age spots (also known as liver spots or solar lentigines). The scientific rationale for using retinoids is primarily based on their capacity to regulate epithelial cell growth and differentiation, stimulate collagen production, and increase epidermal cell turnover.

Several clinical studies have shown that topical retinoids can improve pigmentation irregularities, including age spots, by accelerating the shedding of hyperpigmented keratinocytes and promoting the growth of new, evenly pigmented skin. Prescription retinoids like tretinoin (all-trans retinoic acid) have the strongest evidence base, but over-the-counter forms such as retinol and retinol acetate are chemically related and are converted to active retinoic acid in the skin, though less efficiently.

According to systematic reviews and clinical trials, regular application of topical retinoids can lead to a modest but significant reduction in the appearance of age spots over several months. However, the strength of evidence for non-prescription forms such as retinol acetate is somewhat lower than for prescription retinoids, leading to an evidence rating of 3 out of 5. Side effects, including irritation and dryness, are common, and sunscreen use is essential due to increased photosensitivity.