Biological Skin Age Estimator

UV sun exposure is the leading cause of premature skin aging (photoaging), responsible for up to 80% of visible aging signs. Other major factors include smoking, poor sleep, chronic stress, dehydration, high-sugar diets, pollution, and lack of skincare. Genetics also play a role but are less modifiable.

Retinoids (tretinoin/retinol) have the most clinical evidence for anti-aging. They boost collagen production, increase cell turnover, and reduce fine lines. Sunscreen is technically the most important product for preventing aging. Other effective ingredients include vitamin C, niacinamide, and peptides.

Prevention is best -- daily sunscreen should start in childhood. A retinoid can be introduced in the mid-to-late 20s, when collagen production begins declining (~1% per year after 25). A basic routine of cleanser, sunscreen, and moisturizer benefits everyone regardless of age.