ABSTRACT
Regulatory Environment 545
References 546
REGULATORY ENVIRONMENT
All-trans retinal or retinaldehyde (RAL) belongs to the group of natural retinoids
issued from vitamin A metabolism. Next to retinol, RAL is the key metabolite as
the immediate precursor of retinoic acid (RA) and can be physiologically stored
in the keratinocytes of the skin. With a similar activity (1) and a better tolerability
than RA, RAL is used as cosmetic mainly in skin aging (2).
