Skin care and moisturizers
For instance, a
heavy-duty moisturizer for the hands will contain
a large proportion of a humectant such as glycerol.
Under normal conditions, however, this would be
too heavy for use on the face, and a lighter formulation
would be more appropriate.
A cosmetic moisturizer designed
to encourage skin hydration will be made up from
a small percentage of water and humectant, blended
with oils and emulsified to form a liquid or cream.
Night creams can be water-in-oil emulsions
as they contain a high proportion of excellent humectants.
The
general rule is that the drier the skin and its
environment, the richer should be the moisturizer.
Younger people tend to prefer
lighter moisturizing products than older generations.
This is because the younger the skin, the greater
is its capacity to retain water, and the more sebum
it produces.
Specialized moisturizers
Cosmetic companies are now producing skin care moisturizer products
that incorporate substances giving |
|
|
|
protection against
ultraviolet radiation, as well as other ingredients
for hydration and exfoliation. Products with sunscreens
are intended for regular daily use, not only for
application during heat waves or on beach holidays.
As we saw in Chapter
4, there is a good deal of scientific evidence
that the daily use of a moisturizer with sunscreen
ingredients can reduce the long-term effects of
photodamage.
Increasingly men, as well as
women, are recognising the need for regular moisturising
and the daily use of sunscreens.
How a moisturizer may change the appearance
of the skin
As we saw earlier (page 28),
the way in which visible light interacts with
skin is fundamental to how we see it and judge
its condition.
There are several ways in which cosmetic
preparations may improve the appearance of the
skin. Application of a simple oil-in-water emulsion
containing glycerol will smooth down the squames
and produce swelling of the stratum corneum. This
mechanism is responsible for the surface-smoothing
effect that |
|
|
