The science behind Vitamin C's superlative impact on skin

Today we’ll put the spotlight on a true superhero of skin health.  An ingredient so important that your skin has two delivery mechanisms to bring it to its surface for protection from the elements.  This ingredient is so essential that when it’s in short supply, your skin immediately suffers, gets inflamed, breaks down, does not heal easily, and is more sensitive to sun damage.

Ladies and gentlemen, I present to you…  (drum roll, please)…

Vitamin C!

It seems almost too good to be true-vitamin C, the one that we take when we are sick, the reason why all kinds of fruits and vegetables are good for you, the almost everywhere ingredient, inexpensive to boot, is the answer to many skin issues that come with ageing.  You should take vitamin C, either as part of your plant-rich diet, or as a supplement, and put it on your skin as well, in the form of serums and creams.  To begin, let’s look at the skin itself-the largest organ in the body, whose good appearance is coveted by all but the most spiritually-advanced among us.  The cross-section of the skin is composed of three layers (as always, this is an over-simplification, but bear with me), epidermis (the outside-facing layer), the dermis (middle layer), and the lower hypodermis layer.  The epidermis acts as a barrier between us and the world, and as we age, this barrier becomes less effective.  It is made up of cells called keratinocites, which are arranged in layers-the closer to the surface, the more differentiated they become, meaning that they produce more and more cross-linked proteins and secrete lipids.  This layer then creates a barrier that’s important for integrity and health of the skin, and it is called stratum corneum.  Be careful will all kinds of exfoliation treatments, such as chemical peels… you definitely can overdo those!  Those ‘dead skin cells’ that the peel removes, dead though they may be, are important for your overall skin health.  That barrier prevents water loss, which is especially prominent in dry winter months.   

One important thing to remember is that the epidermis lacks blood vessels, so the delivery of nutrients to the outermost layer of the skin is limited.  For vitamin C, however, there are protein carriers that deliver it to the outer skin layers.  That’s why it is good to supply vitamin C to the skin via cosmetic products-creams and serums-in addition to nutritional intake.

The dermis is where all the collagen and elastin are-the protein structures that provide skin elasticity.  Dermis doesn’t have many cells, aside from fibroblasts, the cells that produce collagen.  And vitamin C enables them to do just that.  It does have vasculature, so nutrients from your bloodstream can reach it easily. 

Healthy skin has high levels of vitamin C throughout its layers.  Since it’s a water-soluble molecule, vitamin C is easily supplied to the dermis via blood vessels. When it comes to outer layer of the skin, protein carriers deliver it to the surface of the skin, where, as mentioned, they cannot get very easily otherwise.  Your skin has two vitamin C transporters (unlike other organs that have only one), as it is very important for this vitamin to reach all layers of your skin.  So, there is a way for our spotlit ingredient to get where it needs to go.  But why does our skin need it?

Many reasons, as it turns out! 

·        Collagen synthesis -it catalyzes collagen production in the dermis.  In fact, vitamin C is essential for collagen production as it is a cofactor for an enzyme that produces it.  As your dermis is supplied with vitamin C through blood vessels, the vitamin C that gets there to help make collagen, comes from your nutrition, not creams-so eat your fruits and vegetables, ladies and gents!  Or supplement, if you so prefer.  Your skin will thank you.

·        Fighting oxidative damage caused by pollution and UV exposure-it neutralizes the free radicals on the skin, which, if left well alone, can do a lot of damage to your skin, not only ageing it, but causing skin cancer as well.  Vitamin C fights UV damage, but this function is greatly enhanced if it is applied in combination with vitamin E and ferulic acid (that’s a topic in and of itself, which we will focus on later).

·        Wound healing-vitamin C speeds up wound healing, and minimizes the appearance of raised scars-this is in direct relation to its role in collagen production.  Supplementation seems beneficial here as well, as vitamin C has a high turnover at the wound site.  In fact, both topical application as well as nutritional intake have shown benefits. 

·        Fighting dry skin-it helps restore the barrier function of the skin, by organizing the stratum corneum layers.  Vitamin C is essential in ceramide synthesis.  Ceramides are the main lipid components of stratum corneum, the outermost layer of the skin. 

·        Brightens skin-vitamin C inhibits melanogenesis (melanin synthesis)-used to treat melasma (skin hyperpigmentation in pregnancy) and age spots. 

In all the biochemical processes that it participates in, vitamin C gets consumed-it doesn’t stay on your skin.  So it’s good to keep taking vitamin C through your diet, as well as applying it topically, so that the skin’s repair mechanisms don’t get diminished by repeated exposure to UV rays or pollution.  The same goes for its shelf life-vitamin C reacts with all sorts of bad actors from the environment and enables the synthesis of collagen and ceramides that keep our skin elastic and good at holding onto its moisture.  But vitamin C is reactive even in the jar, and that’s of course a problem.  As we said above, you want vitamin C to protect and rejuvenate your skin, not react with air, which it actually does, and this process is sped up by light and some metal ions.  That’s why the jars of your product containing vitamin C should be dark, to protect it from light as much as possible, and they should be stored in a dark place.  The oxidation product, dehydroascorbic acid, has a strong color, so as soon as you see the discoloration of your serum (it starts as light yellow, but will get darker with time), it’s time to pitch it.  The product of that oxidation is nontoxic, so it won’t harm you, but it won’t give you the benefits you are looking for either. 

If your product contains pure ascorbic acid, it needs to be formulated so that it is in its neutral form-and that means, that the product you’ll be applying to your skin will have low pH, usually below 4.  The neutral form penetrates skin more easily, so it’s necessary for the effectiveness of the product.  What that practically means, however, is that when you put it on your face, it might tingle or sting a little.  Not a lot of people like that, so that may be a deal breaker for many.  Fortunately, there are other vitamin C derivatives that can be used that don’t have that problem (vitamin C palmitate or magnesium ascorbyl phosphate, for example).

In summary, it’s easy to see why vitamin C is one of our favorite ingredients.  With a myriad of benefits and practically no downsides, it should be a part of your routine, too.  It can be used day and night, but due to its role in UV protection, if you only choose one daily application, make it be the morning one.  It’s not a substitute for sunscreen, but it does play an important role in skin protection.

Next, we’ll look at another superhero status ingredient, that no cream should be without, and that is vitamin E. 

Till next time,

Dr Lasio