Sleeping better helps, but it often is not enough to give dull skin its light back. A flat complexion comes mostly down to cell turnover: when it slows, dead cells stay on the surface longer and the skin reflects light less evenly, looking dull even after a full night's rest.
The real causes of dull skin
Beyond slower cell turnover, stress counts, as do daily exposure to smog and pollution, the change of seasons, and a product routine that no longer suits the moment your skin is going through.
It is usually several things together rather than one alone, which is why a single fix, whether sleep or one particular serum, is rarely enough by itself.
What does not work
Adding yet another brightening serum on top of skin that has not first been exfoliated and properly assessed gives, at best, a temporary effect that fades within hours.
What genuinely helps
A treatment combining exfoliation and targeted hydration, chosen after understanding why your skin is not reflecting light at the moment, gives results you can see from the first session, and results that last longer.
