Every day your skin faces a barrage of assaults: UV radiation, pollution, other environmental toxins (e.g. fragrances, many other synthetic inactive ingredients in your cosmetics). Antioxidants like Vitamin C help to fight off free radicals and the damage they wreak on your skin. But not all Vitamin C formulas are created equal. What skin care benefits you can reap from Vitamin C depends on how well your skin can absorb it.
On the Level: Vitamin C Absorption through the Epidermis
The primary method for Vitamin C absorption is through dietary intake. Vitamin C is readily absorbed through the intestine wall and transported throughout the body. The foods you eat determine your plasma Vitamin C levels, which play an important role in many metabolic functions. However, the skin health benefits Vitamin C provides are not always fully realized just because you have sufficient plasma Vitamin C levels. To get maximum benefits, you need to deliver Vitamin C directly to your skin, which is possible through topical applications—skin creams, lotions, serums, etc.
As one of the water soluble vitamins, Vitamin C is a small enough molecule that it can readily pass (diffuse) through cell membranes to be absorbed through the epidermis and transported to the underlying dermis where it can directly fight oxidative stress that leads to wrinkling, hyperpigmentation and development of skin cancers. However, Vitamin C absorption through the skin greatly depends on the pH of the Vitamin C application. Because the skin is slightly acidic, so, too, must the Vitamin C delivery system be acidic. A pH below 4.0 is ideal. The concentration of Vitamin C also impacts absorption. You don’t necessarily absorb more Vitamin C just because a product has a higher concentration of Vitamin C in it. Maximum absorption seems to happen with 20% Vitamin C. Higher concentrations will likely lead to excess Vitamin C being transported from the tissues into the blood where it will eventually be filtered out and excreted in urine.
One major challenge to topical delivery is getting Vitamin C to live cells beneath the (dead) stratum corneum. The key to effective topical delivery of Vitamin C is exfoliation—removing the uppermost layer of dead cells allows Vitamin C formulas to be applied directly to live cells. Chemical peels, microderm abrasion and other gentle mechanical exfoliants will all work.
Dose and Delivery: Vitamin C Derivatives and Chemical Stability
Once you have cleared the way for effective topical Vitamin C delivery, you want to make sure that the Vitamin C you apply to your skin will be effective. Effectiveness depends on two factors: the potency of the Vitamin C derivative used in your skin care formula and its chemical stability.
The purest form of Vitamin C, the one that is naturally bio-available, ready to fight oxidative stress on the cellular level is L-Ascorbic Acid. There are a number of other derivatives of Vitamin C, which can do all the things pure Vitamin C can do…after they are converted to L-Ascorbic Acid in the body. However, the chemical conversion of these other derivatives ultimately means that measure for measure, these derivatives deliver less bio-available Vitamin C to your cells.
The chart below summarizes the Vitamin C derivatives commonly found in skin care products and their potency:
|
Vitamin C Derivative
|
Potency
|
| L-Ascorbic Acid |
100% |
| Sodium Ascorbate |
95% |
| Magnesium Ascorbyl Phosphate |
60% |
| Sodium Ascorbyl Phosphate |
55% |
| Ascorbyl Palmitate |
40% |
| Tetrahexyldecyl Ascorbate |
13% |
The potency refers to the amount of Vitamin C that is actually delivered to your cells. In one gram of L-Ascorbic Acid, one gram of Vitamin C is delivered to your cells, but for one gram of Sodium Ascorbyl Phosphate, for instance, just over ½ a gram of Vitamin C is delivered to your cells. That means that when skin care products use derivatives of L-Ascorbic Acid, they must use a lot of the compound to deliver a sufficient amount of Vitamin C that can actually help combat the signs of oxidative stress.
Regardless of the potency of Vitamin C, whether or not it will be effective on your skin depends on its chemical stability in the skin care formula. Vitamin C will begin to neutralize free radicals anywhere, even in the formula that makes up its delivery vehicle to your skin—i.e. the other stuff in your lotion or serum. Free radicals may be introduced to the delivery compound because of natural degradation caused by heat, light or air exposure. If your Vitamin C skin care product is brown, its antioxidant properties have already spent; it will not do any good on your skin.
To stabilize Vitamin C (i.e. suspend its antioxidant activity until it gets absorbed by your skin), it must be carefully processed and stored. Formulations that compound Vitamin C with another antioxidant, like Vitamin E, effectively preserve the stability of Vitamin C. (Research also shows that Vitamin E boosts the effectiveness of Vitamin C and vice versa.)
Hale Cosmeceuticals’ Commitment to Pure Vitamin C
All Vitamin C products produced by Hale Cosmeceuticals contain only 100% pure L-Ascorbic Acid. So, ounce per ounce, they deliver the most potent form of Vitamin C to your cells. We also use cold water processing to preserve the chemical stability of the L-Ascorbic Acid, and our formulas capitalize on the antioxidant synergy of Vitamin C and Vitamin E.
