Vitamin C has been one of the hypes of 2018 in natural skincare, but it is not the easiest ingredient to work with. As a result, we’ve noticed a good many questions about vitamin C among our students and in our Facebook community. So, we decided it was high time to tackle vitamin C, or L-ascorbic acid.
In this first of a series on vitamin C, we look in particular at its benefits as an active ingredient to include in high-performance skincare formulae. In future posts, we’ll look at the forms it comes in that are suitable for the natural skincare formulator to incorporate easily; and then test out some skincare recipes with vitamin C starring as an active ingredient.
Before we start on its benefits, let’s refresh our minds about vitamin C, which despite being a familiar vitamin, has some surprises in store.
Vitamin C: its nutritional background
Humans are one of the only mammals, together with monkeys and guinea pigs that cannot synthesise vitamin C (L-ascorbic acid) on their own. It is therefore considered an essential nutrient that needs to be supplied in our diet.
Vitamin C deficiencies were very common in the past. When we look back in history, we come across scurvy, a disease caused by extreme vitamin C deficiency and that was potentially fatal. Luckily, in our day and age, scurvy is rare.
Vitamin C Fact: the term “ascorbic” literally means “against scurvy” (‘a’ means “without”; and “scorbuticus” means scurvy).
However, varying degrees of vitamin C deficiency are still possible and more prevalent than you think. It can be caused by mental and/or physical stress, smoking (each cigarette costs you around 25mg of vitamin C), antibiotics, and the regular taking of antidepressants, aspirin and oral contraceptives, as well as over consumption of alcohol and refined sugar. This probably means a good many people suffer a vitamin C deficiency even if they don’t realise it.
Vitamin C can be found in many fruits and vegetables. Examples of sources rich in vitamin C are: acerola cherries, rosehips, blackcurrants, red peppers, parsley, cress and leafy greens like spinach, cabbages, Brussels sprouts, broccoli and kale; as well as cauliflower; along with tomatoes, citrus fruits, melon, pineapple, berries, kiwi fruit, and strawberries. Vitamin C comes bundled in lots of delicious foods which we could easily make part of our daily diet.
Vitamin C and our skin
Not only is vitamin C vital inside our body as a nutrient, it can also be found in the following layers of our skin:
• The epidermis: this is the outer and top layer of our skin. Here, we find melanocytes which are responsible for making the pigment melanin in our skin.
• The dermis: this is the deeper layer of our skin, below the epidermis. Here, we find fibroblasts that make collagen.
We’ll come back to melanin and collagen later.
Our vitamin C content in both these layers can be compromised on account of:
• excessive exposure to UV light; and
• excessive exposure to pollutants, like cigarette smoke and ozone.
Vitamin C is transported through the bloodstream to the skin. So-called transport proteins for ascorbic acid are found in cells within all layers of the skin. Keratinocytes in particular have a high capacity for vitamin C transport.
Vitamin C: its properties and use in high-performance formulae
Vitamin C as an antioxidant
Free radicals are highly reactive molecules with unpaired electrons. They can damage various vital molecules in the body such as proteins, lipids, and nucleic acids such as DNA and RNA.
They can occur through the skin’s exposure to toxins and pollutants but occur mostly through exposure to UV radiation. Side note: anti-pollution skin care is a fast-growing sector of the cosmetics’ industry. See our post on how to make anti-pollution skincare.
They are generated also through our normal internal metabolism. The internal production of free radicals increases with age, while the defence mechanisms that counter them decrease. This imbalance leads to the progressive damage of cellular structures, and results in accelerated ageing.
Antioxidants are substances that can provide protection against oxidative stresses by scavenging these free radicals.
Vitamin C works in two different ways to counter free radicals:
Firstly, vitamin C itself is an effective free radical scavenger as it provides electrons to neutralise free radicals; and secondly, it regenerates alpha-tocopherol (vitamin E) levels which helps counteract the effects of free-radical skin damage.
Vitamin C as a collagen promoter
Collagen is a protein and the primary structural component of the dermis. It is responsible for strengthening and supporting our skin. As we age, these building blocks deteriorate as the production of collagen slows and elastin, another protein, is less springy. This leads to wrinkling and other typical signs of skin ageing.
Vitamin C both influences and promotes quantitative collagen synthesis as well as qualitative changes in the collagen molecule. So, it gives our skin a double whammy helping it look firmer and suppler and overall healthier and younger.
Vitamin C and photo protection
First, we must stress that vitamin C cannot – repeat, cannot – be used as a sunscreen because it does not absorb light in the UVA and the UVB spectrum. You can find out more about sunscreens in formulae on these two posts:
However, vitamin C can limit the damage induced by ultraviolet light exposure because its antioxidant function helps protect the skin from the free radicals that are caused by this UV exposure.
Topically-applied combinations of vitamin C and vitamin E are more effective in preventing photo damage than either vitamin alone.
It also aids in reducing photo damage thanks to its ability to regulate the synthesis of the structural protein collagen.
Vitamin C as a depigmenting agent
Melanocytes in the epidermis make melanin. Melanin is the brown pigment that produces our normal skin colour and what makes our skin tan. When our skin comes into contact with rays of sunshine, melanin particles gather and absorb these rays as they pass through the upper layers of the epidermis. These clusters of melanin form a protective shield over the keratinocytes.
As we grow older, our skin can be characterised by hyperpigmentation which means that patches of skin become darker in colour in comparison with the normal surrounding skin. This darkening occurs when an excess of melanin forms deposits in the skin.
As formulators, it’s our aim to help reduce this hyperpigmentation without causing undesirable hypopigmentation – loss of colour in the skin – and without irritation in the surrounding and normally-pigmented skin.
Melanin is produced by the enzyme tyrosinase located in the melanocytes within the bottom, or stratum basale layer of the skin’s epidermis. As natural, organic cosmetic skincare formulators, we do not use products that have an effect below the cosmetic (ie. epidermal) layers of the skin, nor do we use ingredients that have a bleaching effect on the epidermis.
Therefore, when you are choosing a depigmenting agent, it is important to check its function. We need to know whether the ingredient could be toxic for the melanocyte or whether it could interrupt the key steps of melanogenesis.
Topically-applied vitamin C has the cosmetic effect of fading of dark spots and brightening the skin.
Vitamin C is often combined with soy and/or liquorice for an even greater effect on reducing the visible signs of hyperpigmentation.
Thanks to all these properties, we can definitely conclude that topically-applied vitamin C is of great value in a variety ways in high-performance skincare.
A note about vitamin C and dry skin
The effects of vitamin C on skin dryness are still unclear. Some research suggests that vitamin C has an effect on trans-epidermal water loss (TEWL) because it promotes the synthesis of barrier lipids, which establishes a functioning stratum corneum with low water permeability. Others mention an increased TEWL when vitamin C is applied to the skin. This is something to keep an eye on in the future.