Vitamin C: Why It's Crucial For Skin & What It Needs To Work

By Brendan Vartan, esthetician & mua / @brendanvartan


Vitamin C is a powerful antioxidant that is naturally abundant in normal skin and is crucial for overall skin health. Why is it crucial, you say?

1. It is an antioxidant that helps protect against free radical oxidative damage from UV rays and environmental pollutants. Oxidative damage can cause dark spots and change the skin structure to result in uneven tone, texture, wrinkles and sagging skin.

2. In addition to its antioxidant abilities, vitamin C also helps to regulate the production of collagen which is crucial for the firmness and support of the skin. 

3. Vitamin C works as an effective and nontoxic depigmenting agent by inhibiting the actions of tyrosinase, the enzyme that catalyzes melanin and other pigments through oxidation.

4. Vitamin C has shown anti-inflammatory activities for conditions like rosacea, acne and can even prevent hyperpigmentation from flare-ups.

While we naturally have vitamin C in our skin, several studies have shown that its levels are lower in aged and environmentally damaged skin.  We can get vitamin C in our diet and while we can benefit from more studies, many studies on vitamin C have also shown that supplementing this with topical vitamin C can be beneficial. The most studied form and the the most biologically active form of vitamin C is L-ascorbic acid. The downside is that this is a very unstable ingredient that degrades when exposed directly to air and light. It is also hydrophilic which means it does not naturally mix well with lipid components of skin making it difficult for delivery. 

However, formulas with the following can help make this ingredient not only effective but can enhance its effects.

1. A formula pH of 3.5 or lower helps improve both stability and permeability to the skin. Those with sensitive skin should be aware that, the lower the formula pH, the more it can irritate skin. 

2. Biologically active L-ascorbic formulas should be between 10 - 20% concentration. Anything above 20 does not increase effectiveness and many even argue that a formula concentration should not go above 18%. 

3. Vitamin E has been shown to enhance the actions of vitamin C four-fold. Additionally, since vitamin E is hydrophilic (water loving) and vitamin E is a lipophilic (fat soluble) antioxidant, they can work to protect both hydrophilic and lipophilic components of cells. 

4. When 15% L-ascorbic acid is combined with specific concentrations of both vitamin E and ferulic acid, the efficiency of vitamin C is boosted to help reduce effects of photodamage eight times above vitamin C alone. (3)

While the focus of this article is L-ascorbic acid, as it's the most studied and most bioavailable form of vitamin C for skin, it should be noted that there are multiple forms of vitamin C's that are available and used in the skincare. A couple of notable forms include magnesium ascorbyl phosphate (MAP) and tetrahexyldecyl ascorbate (THD). Unlike L-ascorbic acid, these are lipophilic (fat soluble) forms of vitamin C and can be stable at a higher pH making them suitable for very sensitive skin types. They are also useful when paired with other skincare powerhouses like retinoids to elevate their effectiveness. However, because they are not pure vitamin C like L-ascorbic acid, they must be converted to be used by the skin. The chemical conversion makes the ingredient less bio-available to your cells and skin. After conversion, MAP has been shown to deliver about 60% of vitamin C to cells and THD delivers only about 13% compared to the potential 100% of L-ascorbic acid. 

It's important to know that just because a product lists vitamin C or even L-ascorbic as an ingredient, does not mean it will do much for skin. Look beyond the price, branding and marketing and you will probably find that many vitamin C formulas are not physiologically effective as they will not show substantial results when compared to those from effective formulations. Unless proper conditions are met in a product (including stability, delivery, proper pH, proper concentrations and supporting ingredients in the formula), they will mainly sit and degrade in the upper layers of skin unable to convert or behave as the biologically active form that skin needs. Worse, a poor formula can cause more oxidation and harm your skin.

As an esthetician who has worked with many formulas for the past 22 years, I can wholeheartedly recommend one to valued clients that meets (and even exceeds) the studied requirements for an effective topical vitamin C discussed in this article - the C+ Skin Defender.  

3. Farris PK. Cosmetical Vitamins: Vitamin C. In: Draelos ZD, Dover JS, Alam M, editors. Cosmeceuticals. Procedures in Cosmetic Dermatology. 2nd ed. New York: Saunders Elsevier; 2009. pp. 51–6. 

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