The 2 forms of Vitamin A, retinol or Retinyl Palmitate, can be referred to as retinol in a cosmetic product. Dr Antoni Calmon explains that both molecules break down in the skin into retinoic acid. All retinoids must be transformed into their final version, retinoic acid, to be effective. Retinyl Palmitate is slightly less effective, but also better tolerated by the skin, as it requires one more conversion step to become retinoic acid.
Retinol esters convert first to retinol, then to retinaldehyde, and finally to retinoic acid.
This makes retinol esters particularly suitable for sensitive skin or for people using retinol for the first time. The founder of PERS has favored this form in Sérum Pro-Rétinol PERS to guarantee high tolerance with no consequent impact on efficacy, provided retinol is applied over time, rather than as a cure.