Alpha hydroxy acids, or AHAs, have been used in low quantites for cosmetic purposes for centuries – Cleopatra bathing in milk is one legendary instance of the use of lactic acid – but they only reached the mass Thai market in the mid-90s, where they’re still going strong.

What are they?
Alpha hydroxy acids are a group of simple, structurally related organic acids that are derived from fruit and milk sugars. Glycolic acid, from sugar cane, and lactic acid, from soured milk, are two of the most common ones used and recommended by doctors to improve the skin. Others AHAs include mandelic acid from apples, tartaric acid from grapes and citric acid from citrus fruits.

How do they work?
As one’s skin ages, it becomes less able to shed unnecessary dead skin cells; the build up of these cells can leave the skin’s surface looking dull. Alpha hydroxy acids, when applied to the skin, stimulate and increase the epidermal cell turnover, a process known as exfoliation. There is some scientific evidence that professional treatments, which can contain up to seventy per cent of an AHA, leave the skin feeling more elastic and smooth, while reducing the visibility of wrinkles and fine lines.

"It makes the skin look fresher, brighter and younger," confirms Bumrungrad Hospital dermatologist Dr Niyom Tantikun. He recommends having one treatment per week for four weeks for the best results. Patients with more sensitive skin – such as those with fair skin – should instead have treatments just once a month.

Once the initial series of treatments is over, the results can be maintained by using weaker over the counter creams once or twice a week. "These creams for home use usually contain a concentration under ten per cent," says Dr Niyom, adding that you should check the product label for information.

The most common side effect, whether AHAs are used at home or under a doctor’s supervision, is reddening of the skin. Complaints in the US have, however, also included swelling, burning, blistering, bleeding, rashes, itching, and skin discoloration. "Doctors should start with a low concentration and increase the strength only when there is no adverse reaction," says Dr Niyom.

DIY vs seeing a doctor
Due to the uncertainty involved in an individual’s reaction to a treatment, it’s advisable to head to a qualified dermatlogist for treatment, rather than a beauty clinic. Samitivej Hospital dermatologist Dr Nalinee Sutthipisal says, "Doctors can better manage the side effects that may occur. They also know about the many different concentrations of products, the pH levels and so on, and are more likely to know what the effect on an individual’s skin will be," Dr Nalinee says.

The extent of exfoliation that occurs will depends on the concentration of the AHA, the other ingredients in the produc, its pH level and, of course, the particular AHA used. "It’s the size of the AHA molecule itself matters," Dr Nalinee explains. "Glycolic acid, for instance, is a smaller molecule, so it has a stronger effect. It’s more difficult to control."

For this reason, she personally prefers to use a mixed fruit acid (which has larger molecules) on her patients, as she believes this maximises the benefits of the treatment, while reducing any long term side effects.

Long-term effects are unknown
Since AHAs have been used for such a short length of time, the jury is still out on their longer term effects. Studies have found that since AHAs strip away the skin’s outer layer, a patient will be more sensitive to the sun. This can lead to an increased risk of photoageing (the ageing of the skin caused by the sun) and skin cancer. For this reason, doctors strongly advise that patients undergoing AHA treatments, or using AHA over-the-counter creams, always wear a sunscreen.

Rajtevee Polyclinic
Mahatun Plaza, Ploenchit Rd
Tel: 252 9251
First time free, then five treatments for Bt1500.

Samitivej Hospital
133 Sukhumvit 49
Tel: 381 6807
Bt600 per treatment

Bumrungrad Hospital
33 Sukhumvit 3
Tel: 667 1000
Usually Bt700, but can vary according to doctor

Bangkok Nursing Home Hospital
9/1 Convent Rd, Silom
Tel: 632 0550
Bt600 to 1000

Bangkok General Hospital
2 Soi 7, New Petchaburi Rd
Tel: 318 0066

/ Health & beauty