skin-barrier function, all the fancy anti-aging ingredients
you splash on your skin are wasted. Let’s put the humble
moisturizer in the spotlight, shall we?
MOISTURIZERS
SKINCARE DECODED • 48 MOISTURIZERS • 49
Corneocyte
Lipid Matrix
Natural
Moisturizing
Factors
(NMFs)
Cermide
Free
Fatty Acid
Why Moisturize
T
o understand the long-term importance of moisturizing,
we should first revisit some of those Skin Biology 101
terms and concepts. Remember, your skin is like an onion—
it’s got many layers. The outermost layer is called the stratum
corneum, or just SC.
Most skincare products are mainly geared toward treating the topmost layer
of the epidermis, the stratum corneum. (If you need a refresher on skin basics,
refer to page 14 to get your bearings.)
Skin Barrier Function 1: Keep the Bad Guys Out and Water In
Your stratum cornem is the outermost layer of your skin. It’s your first line
of defense against water loss and outside aggressors. Your moisturizers, in a
nutshell, are there to help support your SC in its barrier role.
Skin Barrier Function 2: The Water-Based Stuff
The other component to healthy skin-barrier function is natural moisturizing
factors (NMFs). NMFs are found in the corneocytes of your stratum corneum
and make up about 20–30% of the dry
weight of your stratum corneum.
These water-based molecules
keep the skin elastic and play
an integral part in the good-
enzyme activity that is key to
healthy cell turnover. Common
NMFs in your skin are sodium
PCA, lactic acid, free amino
acids, and urea. Remember:
Healthy cell turnover = healthy
skin barrier = healthy skin.
SKINCARE DECODED • 48 MOISTURIZERS • 49
DEHYDRATED
IRRITATED
AGING
Allergens
All the Woes of
Dehydrated Skin
Your stratum corneum
has it pretty rough: The
beatings of external
allergens, pollutants,
UV rays, weather
changes, and just
plain aging can really
take a toll on the SC
and prevent it from
doing its barrier job
properly. When these
stressors impact your
barrier function, water
loss leads to dehydrated, irritated
skin—and dry skin has long-term
consequences. Neglecting to moisturize leads your poor stratum corneum
into a vicious cycle: increasing water loss, letting in outside aggressors,
causing inflammation, and leading to more dehydration and less absorption
of moisturizers. Uncorrected, this cycle may lead to short-term nuisances like
itchy, flaky skin—which turns into fine lines and wrinkles in the long term!
This means that a solid moisturizing strategy that evolves with age and the
season is one of the most important steps to keep your skin in tip-top shape.
The Takeaway
As boring as skin moisturizing may sound, without this basic step, the stratum
corneum’s job gets a lot harder: Layers below the SC are left not as hydrated,
our bodies end up less protected from outside toxins, and further skin damage
inevitably escalates the aging process. If you don’t have time for all the other
serums, elixirs, or masques, just grab that jar of lotion and slather away.
SKINCARE DECODED • 50 MOISTURIZERS • 51
The Science of Moisturizers
E
ven though scoping out a good moisturizer may seem confusing, there’s
actually some method to the madness. You can divide moisturizers into
three categories of ingredients based on their function: humectants, emollients,
and occlusives. These three categories work together to fullfill your skin’s
moisturizing needs. Understanding how these ingredients work, and finding a
balance of the categories, is the key to cracking your skin’s moisturizing code.
The reality is that your skin will constantly change.
So, instead of hitting the reset button and tossing
out your current moisturizer—the one that took you
forever to find—figure out which of these categories
you might need just a little more of, and you’ll
master your moisturizing needs through the seasons.
Hopefully, thinking about it in this manner will help you
confidently troubleshoot and adjust your moisturizing
routine when your skin decides to be dramatic.
Category 1: Humectants (The Water Stuff)
Humectants are water-grabbing ingredients that help
your skin maintain a healthy moisture level, which is
key to maintaining that desirable, supple feel. Your
skin naturally has its own water-holding system in the
form of natural moisturizing factors (NMFs), and the
humectants in skincare are there to support them. Some gold-star humectants
used in moisturizers are glycerin, hyaluronic acid, and glycols. Humectants
are so important that many skincare products are humectant-centric, such as
essences, ampoules, hydrating serums, and mists.
Who needs humectants? From the oiliest to the dryest skin, every type can
enjoy the benefits of humectants.