For the Surgeon
Articles of Interest
Are you using Vitamin C, or it’s breakdown products?
I hope this little article will help you to understand more about vitamin C, which has gained in popularity but has not achieved its real place in skin care because of various controversies about it. First of all, vitamin C, (ascorbic acid), is inexpensive and easy to obtain but unfortunately, it is unstable and does not last long. On the other hand, stable versions of Vitamin C are expensive and are usually trashed by companies selling ascorbic acid products. So where do you stand? Are you using an active product or are you using a degraded cheap product or maybe an ineffective but expensive one? We need to understand what form of Vitamin C we can get, when the various forms are indicated and how best to use them.
First of all let’s deal with the myths about natural ascorbic acid. Ascorbic acid is one of the most important vitamins in our lives. The exact chemical configuration of natural vitamin C is described as l-ascorbic acid. That means that if polarized light is passed through ascorbic acid crystals, then the light is twisted to the left. When we synthesize vitamin C then d-ascorbic acid is created and as you have probably guessed, it is efiniti “d-“ because it twists light to the right. In fact synthetic ascorbic acid comprises both d- and l- forms and they can be separated – of course this adds some expense, but not much. It just so happens that virtually all “natural” ascorbic acid that is used in the manufacture of cosmetics is synthesized, but it has been “purified” and made natural by excluding the d-ascorbic acid. Although this ascorbic acid is synthesized, it is true “natural” vitamin C.
Ascorbic acid is commercially available as a dry powder (technically called dehydro-ascorbic acid), which is relatively stable and is white in colour. When ascorbic acid powder is exposed to light and air, it slowly decomposes to oxidized ascorbic acid. When ascorbic acid crystals are mixed in water, the solution, as its name implies, has an acidic pH. Under natural conditions the pH can easily be 2 or lower, depending on the concentration. Obviously the greater the saturation, the lower the pH. And the lower the pH, the more stable the ascorbic acid solution. However, it is much less stable than dry powdered ascorbic acid and rapidly decomposes to its oxidized form. I have found that under the best laboratory conditions, ascorbic acid gels even with so-called “stabilizers”, only last at it’s intended concentration for a maximum of three weeks. Therefore, a solution of ascorbic acid, even in a gel, has a limited shelf life and once the solution has been made up, it should be used within three weeks to get the optimum levels of vitamin C. It is easy to see when ascorbic acid has become oxidized: it becomes a yellowish brown in colour. When the solution starts to turn a pale yellow, then one already has less than the original concentration of vitamin C. Many manufacturers claim to have, say 10% ascorbic acid in their product and because ascorbic acid is so unstable they must “overage” the product and add say 25% more, which means that they have 12.5% ascorbic acid in the final product immediately after manufacture. The light yellow colour develops within a few days and by then the concentration may have dropped to 10%. By four weeks, it is likely that the concentration has dropped to about 5%, which is only half of the concentration that was intended. By three months, you can forget about achieving any enhanced vitamin C effects. So in other words, check the date of expiry on your ascorbic acid products. Also check the list of ingredients. I cannot understand why any manufacturer of ascorbic acid products would want to include a yellow brown or any other colour into their product. There is no aesthetic reason, neither is there a functional physiological reason. I leave you to decide what the motives could be. Therefore, check with your supplier and find out if the ascorbic acid product they sell you has any colourant in it
26 October 2002
