Vitamin C is an essential requirement for the growth and repair of tissues in our body and skin, but because we cannot produce it ourselves, we must rely on external sources to receive vitamin C:
Topical vitamin C can offer an array of age defense related skin benefits.
- As an antioxidant, it fights against free radicals, making it a great sidekick to your SPF!
- As a cofactor, a helper molecule, in the collagen formation pathway to improve fine lines and wrinkles
- Even skin tone and discoloration by blocking the pigment synthesis pathway
The form of vitamin C used by the body is L-ascorbic acid and is very well- studied. However, it is unstable and has formulation restrictions to be effective, making it difficult to work with. Although it is water-soluble, when used in water-based formulas, it loses efficacy very readily and undergoes oxidation. Formulas must meet very specific requirements for it to be stable and effective to penetrate skin, such as having a lower pH of at most 3.50. The downside is that it may sting or be irritating for more sensitive skin.
Due to these limitations, newer forms or derivatives of vitamin C have been created.
Tetrahexyldecyl ascorbate, THD ascorbate for short, is a stable vitamin C ester derivative. It can also be formulated up to a pH of 6.50 and is considered safe to use up to 30%, even when used with a retinol containing product.
When applied topically, THD ascorbate converts from the ester to L-ascorbic acid through cytosolic esterase that are prevalent in the stratum corneum, the outer layer of our skin. This conversion may seem to be a slower process to obtain vitamin C’s skin benefits, but unlike water soluble L-ascorbic acid, THD ascorbate is actually oil-soluble and is thought to have better skin affinity and penetration. The stratum corneum is mainly composed of lipids, so ingredients that are oil-soluble or lipid-loving may be absorbed more easily through this layer.
With many advantages, THD ascorbate is extremely versatile and even tolerable by more skin types, including sensitive skin.
THD ascorbate can be found in our Asta C Vitamin C Age Defense Serum.