Vitamin C is a potent water-soluble antioxidant which occurs naturally in human skin. It helps to protect the skin from reactive oxygen species (ROS), treat and prevent changes associated with photoaging, promote collagen production and tissue healing.
Only a small fraction of oral supplementation of vitamin C could be available in the skin, hence we can only rely on topical application of vitamin C to get the desired benefits.
Benefits of vitamin C:
A) Anti-oxidative: When skin is exposed to UV ray it generates reactive oxygen species (ROS), which can lead to chemical alterations of the cellular DNA and the cellular proteins, including collagen. To combat these oxidative stresses and decrease collagen degradation, vitamin C neutralizes free radicals.
B) Photo-protective: It prevents hyperpigmentation. “Vitamin C interacts with copper ions thereby decreasing the melanin formation.”
** “Although vitamin C provides photoprotection by itself, it works best in conjunction with Vitamin E, which potentiates the action of vitamin C four-fold.”
** “To optimize UV protection, it is important to use sunscreens combined with a topical antioxidant. vitamin C does not absorb UV light but exerts an UV-protective effect by neutralizing free radicals, while this effect is not seen with sunscreens.”
C) Anti-pigmentary: It helps treating photoaging and hyperpigmentation.
**Since vitamin C is not stable it is often combined with other depigmenting agents such as soy and liquorice to be more effective.
D) Antiaging: Vitamin C is essential for collagen biosynthesis; it also stabilizes collagen fiber.
In order for Vitamin C to be effective it has to penetrate and be delivered into the dermis in an adequate quantity and convert to the active form of vitamin C in the skin which is ascorbic acid.
To find out the likelihood how effective a vitamin C product is we have to ask:
1. What type of vitamin C it is?
2. What is the concentration of vitamin C in the formula?
3. What is the Ph?
4. What are other ingredients in the formula?
5. Does it contain water?
6. What is the delivery system used?
7. Is the packaging air proof?
8. The amount of usage.
Most common types of vitamin C:
1. L-ascorbic acid (LAA)
+ is the most active form of vitamin C.
+ is hydrophilic (loves water) and unstable molecule, hence the poor penetration into the skin because of the hydrophobic (hates water) character of the stratum corneum.
+ is a charged molecule, which further limits its penetration.
+ pH below 3.5 in aqueous solution is an effective method of improving its stability and permeability.
+ harsh on the skin because of low ph.
+ Ferulic acid aids in both stabilization of the molecule and achieving an acidity of a pH below 3.5.
+When exposed to light & air, it becomes inactive, oxidises extremely fast and degrades to acids that are very irritating to the skin.
2. Magnesium ascorbyl phosphate (MAP)
+ Less effective than ascorbic acid.
+ Is the most stable derivative of vitamin C.
+ Is lipophilic (loves oil) molecule is easily absorbed into the skin
+ not as sensitive to light and air as ascorbic acid.
+ less irritating and not as pH dependent as Ascorbic acid.
+ has a hydrating effect on the skin and decreases transepidermal water loss.
+ It is also a free radical scavenger that is photoprotective and increases collagen production under laboratory test conditions.
4. Ascorbyl palmitate
+ It is an ester of ascorbic acid and palmitic acid.
+ Is lipophilic. The lipid solubility of palmitic acid enhances the penetration of ascorbic acid into the skin.
+ It is a stable derivative of the active vitamin C.
+ It is effective at a neutral pH, which means that it is non-irritating on the skin.
Vitamin C is available in the form of creams, serum and powder. The best option is the colorless vitamin serum. Studies have shown that the best and most effective form of vitamin C is Ascorbic Acid. It works best when it is paired with vitamin E. Ferulic Acid helps to stabilize vitamin C in the formula & enhances the effectiveness of vitamin C and E. Lecithin also does a great job in enhancing the penetration of ascorbic acid molecules.
The higher the concentration of vitamin C the more the efficiency and absorption; but only up to 20% ;“The half-life (degrading time) of vitamin C in the skin after achieving maximum concentration is only 4 days.”
**If your skin can tolerate it the concentrations of 10% or 15% will give better absorption.
Vitamin C is stable and absorbs well if the PH remains below 3.5. At this pH, the ionic charge on the molecule is removed and it is transported well across the stratum corneum. Look for vitamin C products with low pH.
** “PH is only meaningful if water is present so it’s less of an issue in the kinds of water free formulas.”
Airless pump packaging is the best to protect vitamin C from air. Avoid products in plastic tubes unless you know they’re used some kind of laminate to act as a barrier to oxygen transmission.
**Avoid clear packages to protect from light.
**The oxidized forms of vitamin C is relatively non-reactive.
**Exposure to UV light reduces the availability of vitamin C in the skin.
**It has also been observed that Vitamin C is a good priming agent and a post-operative agent for the prevention of erythema following laser resurfacing.
**Smokers have been found to have low vitamin C levels in the dermis.
**As UV light lowers tissue vitamin C levels, it is best to use vitamin C after exposure to UV light and not prior.