DHA: How it Works
When DHA
(dihydroxyacetone ), a colorless 3-carbon sugar, is applied to the
skin a chemical reaction with amino acids in the surface cells of
the skin occurs. A browning, or tanning, effect is produced. DHA
does not damage skin -- it only affects the outermost cells of the
epidermis. DHA carries less health risks than any other method to
achieve a tanned appearance without sun exposure. DHA has been
approves for sunless tanning by the FDA.
How Quickly Does it Act -- How Long Does
it Last
The tanning action usually appears within an
hour of application. Maximal darkening may take 8-24 hours to
develop. An artificial tan produced by DHA will last until the dead
skin cells rub off, usually 5-7 days with a single application.
How is DHA Formulated
There are many self-tanning preparations
containing DHA on the market and many will claim to be best
formulation available. Concentrations of DHA
can range from 3 to 10%. This may coincide with
product ranges that list shades as light, medium, or dark. A lower
concentration (lighter shade) product may be better for new users as
it is more forgiving of uneven application or rough surfaces. Some
formulations will also contain moisturizers. Alcohol based
preparations will be more suitable for oily-skinned users.
Technically, DHA provides some minimal, short lived protection
against UV rays. Alpha hydroxy acids promote the sloughing off of
excess dead skin cells so should improve the evenness of
coloration. Other ingredients may be added to facilitate
application or to make the color last longer.
Care and Handling of DHA Solutions
DHA is temperature sensitive and degrades at
warmer temperatures. Consult the handling directions for your
particular solution as it may have been prepared to increase
stability at higher temperatures. As a general rule of thumb,
storing your DHA solution at a 60-70 degree range would be ideal.
But storing the solution at a temperature below 80 degrees would be
adequate. Refrigeration should not be harmful to any of the
ingredients in your solution. Air also causes the DHA to degrade
rapidly. Any left over material from a spray session should be
returned to an airtight container.
Application Safety
DHA is listed as a color additive for use in
adding color to the human body. The Food, Drug, and Cosmetic Act
authorizes the regulation of color additives. The use of DHA in
cosmetics is restricted to external application. External
application specifically excludes the lips or any body surface
covered by mucous membrane. Also, no color additive may be used in
cosmetics intended for use in the eye unless the color additive is
specifically permitted. Obviously, applying DHA as a spray or mist
may present some challenges in complying with FDA proscriptions.
Therefore, salon staff should take extra care in informing clients
to avoid breathing the sunless product during the application
process. Consumers should also try to avoid direct application of
the product into the eye area, and use a lip balm or other barrier
product on the lips and in the nostrils to avoid contact with mucous
membrane. There should be proper ventilation for staff and clients
in the sunless application area of the salon.
How to Achieve Best Results
The final result of a DHA sunless tan will
depend on the formulation used, the operator's application
technique, and the client's complexion type. Some application
techniques to achieve a maximal DHA tan are: Prepare skin by
cleansing then by exfoliating using a loofah or exfoliant. This will
avoid uneven application of color. Apply to skin in thin layers wherever you want color, less to
thicker skin, as color is maintained longer in these areas. To avoid
uneven darkening on areas such as the elbows, ankles and knees,
remove excess solution over bony prominences with a wet cotton cloth.
Wash hands immediately after application to avoid tanned palms.
Alternatively, wear gloves to apply. To avoid staining of clothes,
wait 30 minutes for the product to dry before putting on clothes.
Don't shave, bathe, or swim for at least an hour,preferably 8 hours, after applying the
product. Reapply regularly to maintain color.
Precautions and Side effects
DHA self-tanners DO NOT provide significant protection to
your skin against the sun. Despite darkening of the skin, an individual is just
as susceptible to harmful UV rays. Although DHA does provide some short lived UV
protection and many products contain additional sunscreen, the stated SPF for
such solutions should only be regarded as effectice for a few hours after
application. It cannot be stressed enough that an overall sun protection
program is still needed for sun exposure. DHA reacts quickly in the outer
epidermis minimizing systemic absorption. Contact dermititis caused by DHA has
rarely been reported. Most causes of sensitivity are likely due to other
ingredients such as preservatives in the preparation.
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