Retinol is the entire vitamin A molecule, and it can
be broken down into thousands of smaller components, of
which one is retinoic acid (also called tretinoin, the
active ingredient in Renova and Retin-A). Skin cells have
a receptor site that is very accepting of retinoic acid.
This relationship between retinoic acid and skin cells
allows a type of communication in which the cell is told
to function normally (that is, not like a damaged or older
cell), and it can, to some extent, conform to that request.
Retinol cannot communicate with a cell until it has been
broken down into retinoic acid. Some of the controversies
regarding using retinol in skin-care products have been
its stability in skin or in a skin-care product, whether
it can be converted into retinoic acid after it is absorbed
into the skin, and how much retinol is needed so that
as it is changed to retinoic acid there is still enough
that can get to the cell. However, over the past couple
of years, some new, stable forms of retinol have become
available, along with lots of impressive research regarding
their efficacy.
It now seems clears that retinol is a beneficial cell-communicating
ingredient and an antioxidant. Simply put, it helps skin
cells create better, healthier skin cells and increase
the amount of skin-support substances. Packaging is still
a key issue, so any container that lets in air (like jar
packaging) or sunlight (clear containers) just won't cut
it, something that applies to most state-of-the-art, skin-care
ingredients. Lots of retinol products come in unacceptable
packaging.
One more point: Neither retinol nor retinoic acid can
take care of anyone's skin-care needs on their own. For
example, they don't replace the need for a well-formulated
sunscreen, AHA or BHA product. AHAs and BHA have a long
history of helping skin to function more normally by removing
built-up layers of sun-damaged skin. Also, retinol should
not be the only ingredient you look for in a moisturizer.
Skin needs a combination of ingredients to function optimally,
including cell-communicating ingredients (of which retinol
is one), antioxidants (to reduce free-radical damage),
and substances that mimic skin structure. Together, all
these various ingredients and elements combine to create
a powerful part of any skin-care routine.
(Sources for this story: Cosmetic Dermatology, Supplement,
Revisiting Retinol, January 2005, pages 1–20; Dermatologic
Surgery, July 2005, pages 799-804; Plastic and Reconstructive
Surgery, April 2005, pages 1156-1162; Mechanisms of Ageing
Development, July 2004, 465-473; and Journal of Dermatology,
November 2001, pages 595-598).