A complaint that comes up frequently is “there are so  many products out there, I don’t know which to choose – what is going to be best for my skin?”  A good starting point is giving your skin the nutrition it needs to function, or as superstar lecturer Florence Barrett-Hill is fond of saying, “what it needs for lunch.”  Even skin which isn’t misbehaving in any way has some basic requirements in order to work efficiently and stay glowing and healthy, in exactly the same way that  your body does.  I’ve already covered Vitamin A and essential fatty acids in previous posts, this post is going to look at Vitamin C and it’s place in daily skin health.

Always read the label!

Incredibly tiny print and long Latin names, coupled with the fact that most wouldn’t have the first clue about what the ingredients actually do, means that not many people bother reading the label on the product box.  Even when you do know what you are looking for you can slowly lose the will to live as well as permanently damage your eyesight trying to determine what is actually in your product.  It’s so much easier to rely on the much more legible information on the front of the box – however, in most cases taking the time to do so can really help you in choosing something that may actually make a difference.  Ingredients are listed in the order of greatest percentage to least percentage, and while it isn’t always true that having a lot of a particular active ingredient is better, in the case of Vitamin C it is a case of the more, the merrier (up to 20% of the total ingredients) so you don’t really want it to be near the end of the list, unless it’s a very short list.

You also need to take note of which formulation of Vitamin C is used, as not all types are able to pass through the skin’s barrier. L-ascorbic acid is one of the most commonly used types and has an acidic pH of at least 3.5.  This version is more stable in higher concentrations but this can cause problems with sensitive, compromised skins and result in irritation, so may not be the best choice for some.  Magnesium ascorbyl phosphate (a water soluble form) is preferable in this case, as it has good effect in significantly lower concentrations which means that potential irritation is greatly reduced. The combination of ascorbic acid, magnesium and phosphate trick the skin cell to uptake a higher dose than just ascorbic acid alone, and once inside the cell this compound is converted to its individual elements and used within the cell.  Ascorbyl tetraisopalmitate (an oil soluble form) is a highly stable version of vitamin C.  Due to its molecular structure (there are four molecules of palmitic acid to one of ascorbic), it is less irritating than L-ascorbic acid and due to it’s lipophilic nature it can pass easily through the lipid bilayers of the stratum corneum and reach the target cell walls.  Ascorbyl palmitate is another very commonly used form of vitamin C, and works in synergy with vitamin E to help protect the cell membranes from lipid peroxidation.  Ascorbyl glucoside has been used effectively along with niacinamide in skin lightening products.  Other beneficial forms include sodium ascorbyl phosphate, ascorbyl stearate, erythorbic acid/isoascorbic acid, aminopropyl ascorbyl pphosphate, vitamin C palmitate, L-ascorbyl-6-palmitate and 3-oxo-L-gulofuranolactone 6-palmitate.

That’s all very interesting, but what does it do?

Vitamin C is probably most well know as an antioxidant, but it also has a marked effect on collagen production, helps reduce pigmentation and has an anti-inflammatory effect.  It needs to be replenished daily due to it’s unstable nature (it oxidises easily), and so it is an important  ingredient in your daily skin care and nutritional programme.

How does it do it?

Vitamin C and the treatment of hyperpigmentation: Vitamin C is an incredibly effective treatment for the prevention and improvement of pigmentation. It blocks the action of the enzyme tyrosinase, and by doing so inhibits all future steps of melanogenesis (formation of melanin, the pigment in the skin).  Tyrosinase is the enzyme which catalyses the reaction between the amino acid tyrosine and other metabolites which leads to the formation of melanin within the melanosome.  The catalyst requires an oxidising environment within which to work, and Vitamin C being an antioxidant effectively alters this.  By blocking tyrosinase, the formation of melanin is reduced and a lightening effect on the pigment patches is achieved.  It is particularly important in this instance to keep feeding your skin with vitamin C, as the skin cells which are producing the hyperpigmentation are doing so because they are damaged, and will continue to do so forever more.  Daily treatment is essential to maintain the positive effects of a treatment programme.

Vitamin C and collagen synthesis:  Vitamin C is one of the ingredients which is required for collagen synthesis and facilitates hydroxylation, or conversion of the amino acids proline and lysine to hydroxyproline and hydroxylysine.  These substances assist the binding together of collagen fibres, creating the strong triple helix structure that you may be familiar with.  Without both vitamin C and iron, hydroxylation does not take place and collagen fails to produce triple helixes, resulting in weak connective tissue.  This is what causes the bleeding gums associated with scurvy, and for the brainiacs out there the word ascorbic comes from the Latin ascorbus, which means “no scurvy”.  It also seems to play a role in stimulating fibroblasts to create collagen (http://www.ncbi.nlm.nih.gov/pubmed/7518857), which is always good news. In addition, it also stimulates the expression of the agent which inhibits the production of the enzyme which breaks down collagen.  So as you can see, it plays many roles in keeping the skin strong.

Interestingly, there is evidence to suggest that vitamin C has a inhibitory effect on elastin synthesis, which initially gave me a bit of a start as I’d always believed that it was a vital ingredient in any anti-aging formulation and this sounded counter-intuitive.  On digging deeper I found this inhibitory effect is in fact anti-aging in itself, as when the skin is exposed to UV radiation it has a boost in elastin production.  While this sounds good (stop right now if you are running out to bathe in the last rays of sun we are having this summer!), it is actually very detrimental to the skin as it isn’t healthy elastin but an accumulation of abnormal elastin that forms in the spaces between the cells.  Over time this leads to a condition known as solar elastosis, characterised by dry, thickened skin with deep furrows and a yellowish colour.  So no, an overabundance of elastin isn’t a bonus in this case.

Vitamin C as an antioxidant:  All the cells of our bodies are constantly doing a dance with reactive oxygen species (ROS), otherwise know as free radicals.  The simple act of breathing is an oxidative process and as every cell in our body needs to breathe, we just can’t avoid it.  What I’m getting to here is that there is no way for anyone to manage a life without encountering free radicals, so what we need to do is make sure we are getting a constant supply of antioxidants to help counteract this.  Vitamin C is highly effective in this capacity throughout the entire body (so be sure to get plenty of fresh fruit and veg in your diet daily) but as far as the skin is concerned it has an indispensable function to protect it from the formation of ROS formed by UV radiation.  What exactly is a free radical?  It’s a compound which is formed when oxygen molecules combine with other molecules, yielding an odd number of electrons.  This means the compound is unstable, and will seek to become stable by stealing an electron from another molecule, leaving that molecule damaged.  Vitamin C enters the field and donates an electron, effectively stabilising the free radical.  It’s got proven benefits to the skin for both pre- and post sun exposure – tests have shown that skin treated with vitamin C prior to sun exposure has noticeably less redness, fewer sunburn cells (basal epidermal cells which have undergone cell death or apoptosis in response to being damaged by UVB), and decreased tumour formation after UV exposure.  Vitamin C also works synergistically with vitamin E, another important antioxidant in the skin, where they both reactivate the other after neutralising free radicals.

Oral versus topical

When talking about using vitamins topically I am often asked whether its necessary to use vitamin based products on the skin, as surely if you eat a healthy diet and perhaps take supplements you will be getting the same effect?  While you absolutely should be eating a diet rich in a variety of fruit and vegetables since your skin reflects your overall health, you have no control over where your body decides to send these nutrients or knowledge of how well you are absorbing them.  Vital organs will always be taken care of first, and whether your skin is producing it’s optimal amount of collagen just doesn’t really hit your body’s survival radar.  If you are looking to deliver vital nutrients to your skin to keep it in optimal health, then using products which deliver these nutrients to exactly where you want them makes sense.

It’s not enough for a product to contain vitamin C, the format of vitamin C, its delivery system, processing, packaging and shelf life needs to be considered too.  Even more so than vitamin A, this ingredient is susceptible to degradation on exposure to light and air so products need to be packaged in a pump dispenser which also protects the contents from exposure to light (i.e. not clear glass), or in a collapsible tube (like an aluminium tube which stays constricted once squeezed).  If the product is in a jar, then once open the active ingredient oxidises and is quickly rendered useless – it still contains vitamin C, but it won’t be doing you any good.

Conclusion

As you can see this is a extremely important ingredient in the maintenance of skin health and structural integrity, and should be included in every person’s daily skin care routine.

References

Cosmetic Chemistry byFlorence Barrett-Hill

Cosmetic Dermatology by Leslie Baumann, MD

Dr Saukar Pamori Telang, Vitamin C in Dermatology (National Institute of Health)