Why does my skin look dull no matter what I do?

Dullness is usually a buildup problem, not a product problem — dead skin cells sitting on the surface scatter light instead of reflecting it evenly.

Skin naturally sheds dead cells roughly every 28 days, but that cycle slows with age, sun damage, and dehydration, leaving a thicker layer of dead cells on the surface. Light bounces off that uneven layer instead of reflecting cleanly, which reads as dull or tired skin — no amount of moisturiser fixes that on its own, since it's a surface-texture issue, not a hydration one.