MoisturizersAs we have seen, even normal skin needs protection
from the effects of simply living. Aging, the sun,
the general environment, all take their toll.
Acquiring the habit of moisturizing the skin, particularly
with a product that contains a sun protection ingredient,
is perhaps the most useful thing to be learnt in
cosmetic care.
If the skin is to remain smooth and supple, it needs
to maintain an adequate moisture level. It is constantly
losing its natural moisture, however, through the
epidermis by TEWL. This water loss is aggravated
by: |
- exposure to the elements - sun, wind, cold
- excessive use of degreasing products on the skin
- central heating and air conditioning
- sebum flow slowing down with age.
|
What
is the best facial moisturizer?
The best facial moisturizer is a product that hydrates the skin, and/or
protects the skin from dehydration. That is, it is designed
to improve water retention in the epidermis, particularly
in the stratum corneum.
Moisturizers are primarily intended
to help the skin to function properly in conditions of
cold and wind. They are usually creams, lotions or serums of a consistency
that varies from light to heavy depending on their content
of thickening agents. These creams are essentially oil-in-water
emulsions, consisting of tiny droplets of oil held
in a watery base, rather like salad dressings: in these
emulsions the watery part is called the continuous
phase. Salad dressings, however, separate rapidly
into their watery and oily
constituents; moisturizers, on the other hand, must not
separate out even during long-term storage. So part of
the skill for a specialist in the formulation of the best facial moisturizer lies in the ability to create a formula that
can hold the oil in the water base for a long time without
separation or deterioration. This is done by the |
|
|
 |
This
bottle originally contained an oil-in-water (o/w)
emulsion, but the important oily ingredients have
separated out from the watery part. Part of the
skill of the cosmetic manufacturer lies in producing
a stable
product that can last for many months. |
incorporation of approved and safe stabilising
ingredients.
An alternative type of moisturizer
is a water-in-oil emulsion, in which the
oily part forms the continuous phase. These tend to be
heavier and more greasy, and are aesthetically
more suitable for use on the dry skin of the hands,
as more of the product remains on the skin and
minimises the loss of barrier lipids on subsequent
washing or sweating. Skilful formulators can produce
water-in-oil (w/o) emulsions with a high proportion
of water. Most people find them pleasanter to
use than greasier products.
Modern oil-in-water emulsions
can be considered for use on dry skin, particularly
on the face, where the greasy nature of water-in-oil
products may be found unpleasant. Oil-in-water
emulsions penetrate well into the skin and can
have a cooling effect. |
|
|
