They have a more difficult time penetrating the skin than retinol and have lower clinical efficacy. They are, however, more stable than retinol and hence easier to integrate into a formulation. With advancements in retinol delivery technology, and depending on the needs of the formulators, manufacturers are increasingly using retinol rather than retinyl esters, owing to retinol's higher performance.

See also:
Retinoic Acid
Retinaldehyde
Retinol
Retinyl Palmitate
Retinyl Ascorbate
Retinyl Retinoate