Basically skin whitening or bleaching is what it sounds. It's the use
 of chemical substances to lighten the appearance of your skin tone and 
even out your complexion by lessening the concentration of melanin. Many
 women use skin whiteners to remove age spots, acne scars, moles, and 
even birthmarks. (Dark spot correctors and products are also whitening 
creams that can contain dangerous ingredients.) However, long term use 
of skin whiteners can lead to increased pigmentation of the joints of 
fingers, toes, buttocks, and ears. The skin on your face can also become
 thinned. Areas surrounding your eyes could darken causing a bleached 
panda effect. Prolonged use can cause premature aging, increase your 
chances of getting skin infections, acne, and poor wound healing. There 
are two active ingredients commonly found in most skin whitening 
products: mercurous chloride and hydroquinone.
Mercurous
 chloride is mercury. If the product is used on large areas of skin, 
this can lead to mercury poisoning. Mercury poisoning is known to cause 
psychiatric, neurological, and kidney problems. Pregnant women can also 
pass unhealthy amounts of mercury on to their unborn children. One 
study, according to WebMD, showed that at least one out of every four 
skin lighteners made in Asia that are sold in the US contain mercury. Be
 sure to always check that your product contains no mercury before use. 
Mercury also can be listed under ingredients on the product label as 
calomel, mercuric, mercurous, or mercurio.
The use of hydroquinone
 has been banned in all products throughout Europe, however, is still 
sold in the United States. Products in the US can contain up to 2% of 
hydroquinone if sold over the counter. With a prescription, one can 
obtain a product containing 4% hydroquinone. If the percentage is not 
listed, do not use (unless you consult with your doctor). When 
considering a product containing this ingredient, be sure to consult 
possible side effects with your physician before you begin use.
Many
 women still remain unaware of the possible side effects and dangers of 
using a whitening product. (I checked my own medicine cabinet and found 
that I have two products containing hydroquinone. Percentages were not 
listed.) Do your research as there are many helpful websites offering 
free information, but always remember that doctor knows best!