The skin
is made up of two main layers: the epidermis on the outside and
the dermis on the inside. Whether you are talking about sun tanning
or self-tanning, the epidermis is where the action occurs. The epidermis
is also made up of layers. The deepest layer of the epidermis, called the
stratum basale (basal layer), is affected during sun tanning. The
stratum corneum (horny layer) is the outermost layer of the epidermis
-- it is this layer that is affected by most sunless-tanning products.
There are several
different kinds of sunless-tanning products available today. People have
been able to pour on a tan since 1960, when Coppertone® came out with
the first sunless-tanning product -- QT® or Quick Tanning Lotion. If
you are old enough to remember this, then you are probably thinking of
the incredibly orange hue this lotion produced. Since then, there have
been several advancements made on the sunless-tanning front. These days,
you can find tanning pills, sunless- or self-tanners and bronzers. You
can smooth, swipe or spray on a light bronze glow or a deep, dark tan.
Many of these products take 45 minutes to one hour to start taking effect,
and once you factor in drying time, you could be looking at about three
hours spent achieving that sun-free tan.
According to the
American
Academy of Dermatology, the most effective products available are sunless-
or self-tanning lotions that contain dihydroxyacetone (DHA) as the
active ingredient. DHA is a colorless sugar that interacts with the dead
cells located in the stratum corneum of the epidermis. As the sugar interacts
with the dead skin cells, a color change occurs. This change usually lasts
about five to seven days from the initial application.
Every day, millions
of dead skin cells are sloughed off or worn away from the surface of your
skin. In fact, every 35 to 45 days, you have an entirely new epidermis.
This is why tans from sunless- or self-tanning lotions will gradually fade
-- as the dead cells are worn away, so is your tan. For this reason, most
of these products suggest that you reapply the sunless- or self-tanner
about every three days to maintain your "tan."
Although gels, lotions
or sprays that contain DHA are said to be the most reliable and useful,
there are dozens of other types of products on the market. Tanning accelerators
-- lotions or pills that usually contain the amino acid tyrosine -- claim
that they stimulate and increase melanin formation, thereby accelerating
the tanning process. At this time, there is no scientific data available
to support these claims.
Another sunless-tanning
product is a tanning pill that contains canthaxanthin, which is most commonly
used as a color additive in certain foods. Although the FDA has approved
the use of canthaxanthin in food, it does not approve its use as a tanning
agent. When used as a color additive, only very small amounts of canthaxanthin
are necessary. As a tanning agent, however, much larger quantities are
used. After canthaxanthin is consumed, it is deposited all over your body,
including in your skin, which turns an orange-brown color. These types
of tanning pills have been linked to various side effects, including hepatitis
and canthaxanthin retinopathy, a condition in which yellow deposits form
in the retina of the eye.
Another popular form
of sunless tanning is the bronzer. These powders and moisturizers, once
applied, create a tan that can easily be removed with soap and water. More
like make-up, these products tint or stain your skin only until they are
washed off.
It's important to
remember that most of these products, unless they contain an added sunscreen,
will not protect you from the sun's UVA and UVB rays. Even products that
do contain a sunscreen won't be of much help, since they lose their efficacy
within hours of application. So, if you're planning to head outside to
show off your new glow, be sure to apply some extra sunscreen.
