Vitamin C is undoubtedly one of the most used actives in cosmetics at all times, since its proven benefits are capable of transforming it into an indispensable ingredient.
Skin aging involves the overlapping of two processes: the chronological or intrinsic, and the extrinsic, resulting from contact with environmental stressors, such as exposure to the sun or smoke. The cumulative result of these biological and functional variations brings aesthetic changes that include wrinkles, loss of elasticity, firmness, reduction of skin thickness, and the appearance of spots.
The mechanisms by which the skin ages are diverse, and from the decrease of the cellular proliferation, increase the degradation of the extracellular matrix as collagen and elastin, until the oxidative stress, caused by the imbalance between the greater presence of free radicals, and the reduction of the production of natural antioxidants of the skin. Oxidative stress stimulates other physiological pathways that accelerate aesthetic changes related to aging.
Vitamin C is the most abundant natural antioxidant in human skin. Most plants and animals have the ability to synthesize this vitamin, but in humans, it can not be synthesized by VITAMIN because of the loss of ability to produce L-glucono-gamalactone oxidase, an enzyme necessary for the production of vitamin C. For this reason, it should be obtained from dietary sources like citrus fruits and green leafy vegetables.
Vitamin C is a cofactor for the enzymes responsible for directly stimulating collagen synthesis, and prevent overproduction of metalloproteinase, which degrades existing collagen.
Studies report that vitamin C inhibits the production of melanin and has an anti-inflammatory effect, being therefore one of the most sought and indicated ingredients for the treatment of cutaneous aging in aesthetic cabins.
In several literatures, vitamin C has always been cited as an antioxidant, depigmenting / whitening of topical use, but with reduced chemical stability. In fact, vitamin C, also known by its chemical name ascorbic acid, is recognized in pharmacopoeial literatures as a physiological antioxidant, an essential cofactor for the synthesis of collagen. However, they appear as colorless crystals or white powder, odorless, bitter and water soluble, which is easily altered when exposed to light, air or moisture.
As mentioned, the formulation with ascorbic acid is quite challenging, and requires the balance of several factors. We know that the skin, besides being a protective layer for the body, is the largest system of interaction with external components. As a consequence, there is a need for safe and stable preparations, with active and adjuvants with effective concentrations, in appropriate forms and conditions, in order to minimize product risks.
Over the decades, researchers have studied and modified the unstable molecule of ascorbic acid through different technologies such as esterification and encapsulation, which have resulted in several stable forms of vitamin C. These stabilized forms of vitamin C (or modified ascorbic acid) ensure a more stable, pH-compatible active for the formulation, with optimum stability for application and metabolism, in a suitable carrier and, very importantly, in a concentration that is proven to be effective and safe.
These stabilized forms still allow for more favorable conditions for the packaging and handling of vitamin C containing products.
It is possible to conclude that the moisturizing, whitening, antioxidant, corneal layer renewal stimulating and collagen synthesis stimulating effects should have proven efficacy and safety of use. And these depend on the sum of the concentration of the active, the vehicle, the pH of the formulation, the skin penetration, and also the chemical stability of the vitamin C form used.
Translated from Bel Col Magazine Brazil.