Ascorbic acid, or vitamin C, is a true superstar of the cosmetic world. The benefits of topically applied ascorbic acid are numerous and backed by clinical experiments.
But there's a catch - ascorbic acid needs to be specifically formulated and it is very unstable when exposed to light and air.
Before we dive into the skincare aspects of ascorbic acid, however, let's set the terminology straight. The term "vitamin C" refers to a chemical called L-ascorbic acid, or L-ascorbate. The “L” refers to the active isomer (there is also a D-ascorbic acid but it doesn't have the vitamin C function).
Ascorbic acid and ascorbate are simply two forms of the same vitamin C. In an acidic pH, the molecule occurs in the form of an acid, and if the pH changes to neutral or basic, the molecule transforms into an ascorbate salt.
There are three main benefits of ascorbic acid in skincare:
1. Vitamin C is the essential helper in the process of the formation of new collagen in our skin. Without it, the collagen strands won't assemble properly, which leads to the loss of function.
Think back to what you learned about 17th-century sailors: on long sea journeys without fresh fruit or vegetables they developed scurvy, a disease that stems from a lack of vitamin C. It presents with bleeding gums, skin sores, and wounds that don't heal properly.
Scurvy, fortunately for us, is not an issue anymore, but the skin still appreciates it if we supply it with some additional vitamin C for better collagen synthesis.
Studies have shown that the application of a 5% vitamin C serum can increase the production of collagen and decorin, increase skin density, and reduce deep furrows in the skin.
This makes it one of the most researched anti-aging and anti-wrinkle ingredients, along with retinol.
2. Ascorbic acid is a powerful antioxidant and the most important water-soluble antioxidant in our body.
Our skin in particular has an intricate system of protection against oxidative stress that consists of glutathione, vitamin C, and vitamin E. Starting with glutathione, these three battle against free radicals and are able to recharge the next one in the row if it loses its antioxidant capacity.
Since vitamin E is the main lipid-soluble antioxidant, the role of vitamin C as its regenerator is all the more important. This is why they are often used together in skincare products.
Aside from the antioxidant activity in our skin, ascorbic acid is also a technological antioxidant, protecting the ingredients in the skincare formula from oxidation.
3. Ascorbic acid has been shown to be an anti-pigment ingredient, helping with issues such as melasma, dark spots, freckles, acne scars, and other pigmentation issues. This is due to the fact that ascorbic acid interferes with the activity of tyrosinase, a key enzyme in skin pigment production.
There are other alleged benefits of ascorbic acid on the skin but these are less researched, usually researched only in test tubes and not on real humans.
These include helping skin cells to multiply, helping with the formation of the skin lipid barrier, stimulating the production of hyaluronic acid in the skin, and preventing the UV-light-induced death of skin cells.
Now, how do we reap the full benefits of this ingredient for our skin?
Clinical research shows that eating fruits and vegetables or taking vitamin C supplements can help your skin from within. This does not devalue using vitamin C topically, especially for people exposed to a lot of oxidative stress or people with aging skin, since this type of skin may need more ascorbic acid than what is taken in from food.
Ascorbic acid, however, is extremely unstable and very prone to degradation, especially when exposed to light or oxygen, or is formulated in a water-based medium.
Luckily for us, you can tell when ascorbic acid has gone bad - the skincare product will start turning brown. One way to avoid this problem in products containing ascorbic acid is to have water-less, very acidic, or carefully packaged products.
Another way is to prepare a special formulation of ascorbic acid called liposomal vitamin C – these are microscopic balls of lipids with the ascorbic acid packed inside. Liposomes not only protect ascorbic acid from degradation but also help it to pass through the epidermis into the deeper layers of the skin.
Ascorbic acid derivatives are alternatives to regular ascorbic acid. Examples of such derivatives include various salts, ascorbyl phosphates, and combinations of ascorbic acid and fatty acids. These are supposed to be more stable and better absorbed into the skin than regular ascorbic acid.
Each of them has its own issues. Some are indeed more stable, but the skin cells take more time to convert them back into vitamin C. Others are still under research, and little confirmed information is known about them as of yet. Magnesium Ascorbyl Phosphate (MAP) is generally deemed the most reliable and reasonably stable ascorbic acid derivative.
Vitamin C in skincare products is generally safe, even during pregnancy and breastfeeding. It is safe to combine with other powerful skincare ingredients such as vitamin E, retinol, niacinamide, and others, especially products with the special liposomal formulations.
Occasionally, stinging, erythema, or dryness may be observed after the use of topical vitamin C. These appear in more sensitive individuals or when using highly acidic and concentrated serums. Care should be taken when applying ascorbic acid around the eyes.
