Your skin will be smoother and more fresh looking; fine lines will disappear; your skin will be brighter and lighter. These are the various claims cosmetic companies make for vitamin C, and in theory the vitamin can indeed help your skin in several ways.

Firstly, Vitamin C is an antioxidant, which means it helps neutralise toxic "free radicals". These are the byproducts of chemical reactions that take place in the body. Smoking, exposure to sunlight and pollution, stress, drugs and a poor diet can all lead to an increased production of free radicals on the surface of the skin. In turn, free radicals speed the skin’s aging process and may also contribute to skin cancer and inflammation. Applying topical vitamin C assists in destroying free radicals, and reduces their harmful effects. "I do use vitamin C cream because it’s an antioxidant," says Samitivej Hospital’s Dr Wilai Thanasarnaksorn, adding that its application also helps prevent new pigmentation in the skin.

Secondly, vitamin C helps in the skin’s production of collagen – an important structural protein of the skin – that slows as a body gets older. When vitamin C is properly delivered to skin cells, it can help reduce fine wrinkles and improve the skin texture, often described as a "boosting" or "rejuvenation" of the skin by cosmetics companies.

In practice, however, there are two major difficulties in getting vitamin C to work. First of all, vitamin C molecules are relatively large and therefore very difficult for the skin to absorb. In dermatologists’ clinics, a process called iontophoresis – where a small electrical charge is administered to the skin – may be used to encourage the molecule to be absorbed. It costs around Bt1000 to 2000 depending on the product used, but is usually used to treat medical conditions such as melasma.

The other problem is that vitamin C is highly unstable. In the presence of air or other oxidizing agents such as light, vitamin C is converted to an oxidized form that benefits neither collagen synthesis nor free radical scavenging. In fact, in poorly prepared or stored products, the vitamin C may be oxidized by the time you apply it to your skin. "The stability of the vitamin partly depends on the process used when making the cream," Apex Skin Centre’s Dr Natipat Supaninachart says. "It can disintegrate within a couple of months of being on the shelf [even unopened]."

There are numerous vitamin C products available for the consumer wanting to test the for themselves. "It’s very hard to say which products are better," says Dr Natipat. "But the main benefit for any vitamin C product off the shelf is its moisturising effect."

If you’d like to give it a go on your own, The Body Shop has a citrus-fragranced vitamin C range, which includes Skin Boost (Bt990 for 30mL), Intensive Night Treatment (Bt990 for 30mL) and SPF 15 Daily Moisturiser (Bt790 for 50mL). The Body Shop emphasises vitamin C’s usefulness as an antioxidant, and claims its products will leave the skin feeling smooth and softer.

Helena Rubenstein also has a range. Available in Thailand since January, it includes a Super Energy Serum (Bt 2,800, 6.8 mL x 4 bottles), Moisture Mousse (Bt1,750 for 200mL), Daily Activating Fluid with SPF15 (Bt 1,850 for 50mL) and Super Energising Cream (Bt1,700 for 30 mL or Bt2,200 for 50 mL) and Anti-Fatigue Eye Care (BT1,500 for 15 mL).

But if you’re a little sceptical now, perhaps wait for a few years before giving the products a go. "Companies who are serious about vitamin C are working hard on how to diffuse it into the skin better, and how to stabilise it," says Dr Natipat, adding that vitamin C is a substance of current great interest to dermatologists.

/ Health & beauty