The obsession with fairness and skin lightening products in Bangladesh and, in fact, throughout most parts of Asia and Africa is rather frightening. It seems all of the major cosmetic companies have come out with one cream or the other, and glamorous celebrities endorsing these make them even more desirable. We don't know much about the contents of these products, except that they have vitamins and sunscreens, and it is usually alleged that these products will make you fairer by 2 to 3 shades.

Leaving the ethical issues of skin lightening aside, there are also major medical concerns that come up because of the widespread use of such products.

Many such products have active ingredients, which used under a prescription of a doctor can be used safely. However, it is difficult to assume that all these creams (even soaps and deodorants) with different lightening extracts are absolutely harmless and even effective for that matter.

The issue with such products is quite perplexing. The ones that have active ingredients that are naturally derived and safe rarely show any actual lightening effect. Whereas the more potent products can have ingredients like hydroquinone, mercury and kojic acid, all of which pose several health risks on usage for prolonged periods.  
Hydroquinone is an active bleaching agent which cannot be used in cosmetics. This is sometimes prescribed in form of creams in low concentrations for the treatment of skin problems like skin scars, melasma, vitiligo and for age spots. This is obviously done so with several precautions, for instance, it is meant to be used for short periods and with plenty of sunscreen. Whenever your dermatologist will give you such an ointment/cream, you will be asked to use sunscreen as hydroquinone makes skin thinner and very reactive to sunlight, if used without sun protection it can lead to sunburn. Hydroquinone also changes the consistency of the connective tissue of skin, it causes spotting and premature aging.

Kojic acid, another product, which has recently been touted as one of the best new methods for skin lightening was studied by the Scientific Committee on Consumer Safety (SCCS) of the European Union (EU). According to their findings, products containing kojic acid in skin whitening agents in concentration of 1 per cent and used only on the face and hands can be safe. When used over the entire body and for prolonged periods and if used after doing chemical skin peels at a salon or from a dermatologist, they can pose major health risks.
Kojic acid has been found to cause cancer and hypothyroidism in rats and enough data does not exist to prove its safety in humans. Kojic acid, though claimed to be safer than hydroquinone, has the same sun damage risks as hydroquinone and though derived from a fungus, may not be as safe as most herbal products.

Both kojic acid and hydroquinone cause dryness of skin, peeling, and contact dermatitis (severe allergic reactions). Hydroquinone creams can cause uneven patchy whitening and permanent skin bleaching.
Mercury is commonly used in skin products as it blocks the formation of melanin. Mercury is also present in makeup as preservatives. It is widely known that mercury is toxic and if present in water, it can contaminate fish. Ingestion of mercury poisoned fish by pregnant women leads to birth defects. Mercury products applied to the skin can cause  kidney damage.

A publication of the WHO states three-fourth of women suffering from nephrotic syndrome (kidney disease) in Africa recovered after they stopped using their fairness creams. Another case report of a 34 year old Chinese woman revealed how she developed nephrotic syndrome after prolonged usage of mercury containing creams. One month after she stopped using fairness creams, the mercury levels in her blood returned to normal and nine months later it came down to safe amounts in her urine. The EU and many African countries have banned the usage of mercury in skin creams, however, there are no strict laws about this in Bangladesh.

Another trend in salons in Dhaka and around the country involves a procedure called fair polish. Unfortunately, no one knows what is used to do this and whether it is safe. It is said that doing a fair polish monthly will give miraculous results and you can look like a different person. The effect of such expensive treatments may be doubtful, but the bigger cause for concern is what these chemicals can do in the long term if applied every month and over large parts of the body, the arms, back, legs, etc. Even the laser skincare industry has tapped into this and started advertising skin lightening services, which basically involves killing melanin cells with laser rays.
Important points

Melanin is good. There is a reason people living in sunny tropical or equatorial regions have more of it. We need this protective substance to prevent sun damage and ageing. It should be more important to have fresh and healthy skin, robbing your skin of its natural melanin will make your skin lighter, but it might not make you look more beautiful. Sunscreen is all you need to prevent skin damage from the sun.

Check labels and ingredients. It is important to know what you are putting on your face and your body. Stop using products with hydroquinone or mercury. Limit usage of kojic acid and other herbal skin lighteners.
Ask your beauty salon what they are using to bleach your skin or for doing a whitening facial or fair polish. Ask us at 'Maya Apa Ki Bole' to know whether these products are safe.

Simplify your beauty routine. Cleansing, toning and moisturising are important. Use a scrub once a week ('Uptan' and semolina are excellent). Sunscreen should be used at all times, whether you are 15 or 50.
Cherish your body, think many times before doing anything that may harm it. Is a lighter skin tone worth the risk of cancer, hypothyroidism, skin reactions or kidney disease? You be the judge.