It’s difficult to avoid seeing those advertisements for skin whiteners plastered across billboards, those images of smiling Thai women with snow-white skin shown on TV and in cinemas, in magazines and newspapers.

In western countries, there’s little demand for whiteners; but in Asian countries, they’re big business. According to the Thai Farmers Research Centre, in 1998 whitening products represented the single biggest stake in skin-care products – 49 percent of a market worth around Bt880 million. But are they safe?

The short answer according to skin specialists is that buying creams over the counter probably is. But you should always ensure the ingredients are listed – some unscrupulous salons may sell creams containing substances banned by the FDA for personal use, and these are the potentially dangerous creams.

Dr Wilai Thanasarnaksorn, a dermatologist at Samitivej Hospital, says that if women want whiter skin they should first consult a dermatologist. "I recommend wearing an antioxidant cream, such as a vitamin C cream, and an SPF15+ sunscreen, applied 15 minutes before going out into the sun. People shouldn’t wear anything else unless they consult a dermatologist first."

Dermatologists can recommend the best over-the-counter brands for a patient’s skin type. "The FDA screens products, so buying them over-the-counter from a proper chemist, or a reputable salon, should be safe," says Dr Wilai.

Dr Dollacha Narindrankura, a skin specialist at Rajtevee Polyclinic, agrees. "The problem is, I think, that people with a poor education can buy creams from a drug store or a beauty shop that the shop has packaged itself – and this can be dangerous. People should only buy products with listed ingredients, so they can check what it is they are putting on their face."

Doctors use the strongest whitening agents to treat actual medical conditions: hyperpigmentation or melasma. Both conditions stem from an excessive production of melanin, the substance that causes the skin to darken. Certain chemicals can help improve these conditions by suppressing that melanin production.

There are two main groups of skin whitening agents, explains Dr Wilai: chemical synthetics and herbs or natural substances. "The first are chemicals with some toxicity – hydroquinone is one of these. Its action is very quick, but used over the long term, or using a cream with a high percentage of it, can lead to permanent confetti-like depigmentation [brown blotches] or ochronosis [dark greyish-blue blotches]. It can also cause redness in the skin by dillating the capillaries."

Unsurprisingly then, this is the chemical that causes the most complications. "Hydroquinone is only safe in the hands of doctors," warns Dr Dollacha. "Also, if you use it for a long time – for years – and you stop, there can be a ‘rebound’ effect, where the skin turns darker than what it was before you started using the cream."

Dr Wilai says that recent studies have suggested that hydroquinone may be mutagenic – that is, cause skin cancer. "So the FDA prohibited its sale over the counter, and now only doctors can prescribe it, because they know when to use it."

More worrying is the possibility of creams containing mercury being sold by unscrupulous vendors. "We aren’t sure if there are still some places selling products with mercury in them, especially in the northeast. Ten to twenty years ago mercury was supposed to be a very strong and effective whitening agent. However, it has renal toxicity – it can lead to kidney failure," Dr Wilai explains. "The FDA prohibited it, but we have found a few cases where the staining on patients faces has led me to think that they may have been using a product with mercury in it."

There are a plethora of other whitening agents. Azelaic acid is a naturally occurring chemical that is not banned by the FDA, but it can still burn or irritate the skin if not used under medical supervision. Then there’s kojic acid, arbutin and alphahydroxy acid, among others … it can be a bewildering list to the uninitiated.

That’s before even starting to consider the naturally occurring whiteners, such as vitamin C, hailed by some in the early 90s as being the next great thing in skin whiteners. "I do use vitamin C cream because it’s an antioxidant," says Dr Wilai. "I believe it will prevent new pigmentation, to some degree."

Plus there are plenty of other natural products that most doctors don’t believe are very effective, but are available over the counter – such as chamomile, mulberry extract, apple phenon, licorice extract and even placenta extract. Dr Dollacha says that most of these creams are really only affecting the skin at a superficial level. "In the short run, they might work, but in the long run, they don’t make any difference. They might help get rid of the dead skin on the skin’s surface, and the new skin will look whiter and brighter. But they will only affect dead skin, so they are safe."

/ Health & beauty