By Hannah Sivak, PhD
Biochemist
Skin Actives Scientific


Ascorbic acid is just one form of vitamin C. We want it, we need it. It is an excellent antioxidant and essential for collagen synthesis. But, in solution and exposed to air’s oxygen, it will oxidize. Rather that doing what skin care manufacturers used to do, i.e. pushing hard to keep it from oxidizing so that it can last one year on the shelf of the department store, it makes more sense to take into account the properties of this valuable active. There are two ways of doing this:

1) You can prepare an ascorbic acid solution fresh every morning, by simply taking a few crystals in the palm of your hand and adding a few drops of water. Refreshing, inexpensive, and it works.

2) Use a form of vitamin C derivative that is more stable and will not oxidize in solution, like the magnesium ascorbyl phosphate (we have in our CHAS serum).

In my opinion, either option is better than trying to imitate an existing product that contains ascorbic acid. Respect chemistry, don’t push, and choose the best active for the job.

Two scare stories inspired by vitamin C

What will happen if you decide to try your hand and prepare your own skin care products? According to the experts, you are in terrible danger, as the following half-myths/half-truths tell us:

1. if vitamins C and E are mixed improperly (i.e. by you and not by the skin care manufacturer) they will auto-oxidize, causing them to become PRO-oxidants, instead of ANTI-oxidants (thus causing oxidation instead of preventing it).
2. The iron in tap water will oxidize vitamin c, making it useless or even bad for you

In my opinion, the problem of oxidation of ascorbic acid is a “fake problem” one of the many invented by the industry to scare people into buying brand X and not brand Y (and scaring you away from making your own skin care products).

It is true that ascorbic acid will be oxidized by oxygen present in the air; it is also true that ascorbic acid, in the presence of metals (like copper, iron, etc.), can participate in chemical reactions that will form undesirable products. Is this dangerous? No. Why?

Oxygen has to diffuse in the solution to where the ascorbic acid molecule is in order to oxidize it. Oxidation will take time, which you can shorten by increasing oxygen concentration, shaking the bottle, heating the solution, increasing pH, etc. In normal circumstances, e.g. a concentrated solution inside a closed bottle, oxidation will be such a slow process that it will not make a significant difference to the effective ascorbic acid concentration in the solution or to the benefits it will provide to the skin. In addition, the acidity of the ascorbic acid solution will help delay oxidation. Just like ascorbic acid is stable enough to make the drinking of orange juice a good idea (even after two weeks in the fridge), it is a good idea to use a cream or serum containing ascorbic acid.

The presence of metals (copper, iron, etc.), can lead to chemical reactions in which ascorbic acid will form undesirable products. For this reason, using distilled water to make a solution is desirable, but NOT critical, as again ascorbic acid concentration will be high, the concentration of iron in the tap water will be relatively low, and time for the reaction to take place will be very short.

Another option when you wish to keep the vitamin C stable for a long time, e.g. years, is to use a derivative like magnesium ascorbyl phosphate (we use it in our CHAS serum). But, if a client wishes to make a serum with ascorbic and ferulic acids, then, why shouldn’t she? I like ferulic acid, it is a good active and it smells nice (like vanilla). Personally, I like using fresh solutions of ascorbic acid because it has a triple effect: it is a nice antioxidant, its acidity will make it work as a very mild peel and the very fine granules will have a "microdermabrasion" effect. But our clients do have other options, and all of them are fine.

A caveat: not all fears are "fake" fears. Playing with acids like glycolic, TCA, lactic, etc. can lead to chemical burns that may results in scarring, infections and who knows what else. Damaging the skin barrier is something that only an expert (M.D., licensed esthetician) should be allowed to do.

What is L-ascorbic acid?
Many molecules that contain carbon have more than a possible structure, because of the peculiar properties of the carbon atom. These are called asymmetric molecules and the old terminology allows for two forms, L and D (levo and dextro) because of the effect a solution has on polarized light. The ascorbic acid we sell at Skin Actives Scientific is the racemic mixture (contains both stereoisomers). Unless you are a biochemist planning an experiment involving ascorbic acid as a cofactor, you will be fine. The miniscule amount of L-ascorbic acid our skin needs is more than provided for by a racemic mixture like the one we sell. The crystals of our ascorbic acid are very fine and ideal for use as a "scrub".