Ingredient Spotlight : Vitamin C

As with anything, the cosmetics industry is also susceptible to trends and fashions, whether that be in packaging, colours, scents or ingredients. One of the ingredients that seems to be slapped into any formulation at the moment is good old “cold-busting” Vitamin C.

 

So what is it? What does it do? What is the efficacy like? Stick with me kids, and all will be revealed.

 

Vitamin C is the biologically active form of ascorbic acid, and in the body this is used to neutralise free radicals that may damage cells- it is a highly effective antioxidant. You may see on the INCI (International Nomenclature of Cosmetic Ingredients) list on the back of your bottle the following derivatives of ascorbic acid: ascorbyl palmitate, magnesium ascorbyl phosphate and trisodium ascorbyl phosphate. These compounds are converted in the body into its active form, ascorbic acid.

So why do products include Vitamin C and its derivatives, what do they claim to do?
Well it is largely used for its antioxidant properties, and its use in protecting against and “reversing” UV damage. Human studies on use of topical Vitamin C application and its effect on photo-protection are limited- yes it does reduce free radicals in UV exposed skin, but it is shown to have no significant benefit on reducing the UV-induced erythemal response (the auto-immune response to sun exposure where the skin becomes reddened and inflamed).

It’s also used to treat acne– it has been demonstrated that a 5% (a high concentration) solution of sodium ascorbyl phosphate was effective against acne.

Vitamin C also helps regulate collagen and elastin synthesis. Collagen is a structural protein that gives the epidermis (top layer of your skin) support. Collagen is susceptible to UV degradation and also as you age, synthesis of it slows and it hardens. This can result in ‘wrinkling’ of the skin. Elastin is a protein that simply gives skin its elasticity. However, it is often overproduced in a response to photo-damage, and Vitamin C helps to regulate its production once more. It has been shown that topical application of Vitamin C of 3-10% concentration for at least 12 weeks can decrease wrinkling and even reverse some of the structural damage caused by UV.

 

 

So why are we not all slapping Vitamin C on our faces every day in any which way? Truth is Vitamin C is a right cheeky minx to formulate with and have it remain active. Ascorbic acid is highly unstable and will degrade when in contact with air, heat or light.  Its derivatives which are more stable, such as ascorbate phosphate have limited permeability – this is its ability to be absorbed into the epidermis to be used in the skin. Its efficacy is also affected by skin pH- it works more effective at a lower pH. Human studies and research on its efficacy when applied topically is also limited. It is also been proven that many of the benefits listed above such as its antioxidant properties and its role in collagen synthesis may also be achieved by obtaining Vitamin C orally (aka through your diet).

 

So my recommendation? Its inclusion in cosmetic products is not unwarranted, and there is no harm in buying products that contain it. However research at this stage is limited and any studies I have read where there have been significant results from topical application of Vitamin C, have been applying it in extremely high concentrations- much higher than is likely to be in any cosmetic product on the market. So for now, put down the orange face wash (a subliminal marketing tool used- ascorbic acid in its effective, non-oxidised form is usually white or just off-white in colour) and reach for the actual oranges instead, and leave the scientists to do they thang until enough research has been done, and its formulation issues have been resolved.

 

Sources: 

Cosgrove MC, Franco OH, Granger SP, Murray PG, Mayes AE. Dietary nutrient intakes and skin-aging appearance among middle-aged American women. Am J Clin Nutr 2007;86:1225-1231.  (PubMed)

Darr D, Combs S, Dunston S, Manning T, Pinnell S. Topical vitamin C protects porcine skin from ultraviolet radiation-induced damage. Br J Dermatol 1992;127:247-253.  (PubMed)

Dreher F, Gabard B, Schwindt DA, Maibach HI. Topical melatonin in combination with vitamins E and C protects skin from ultraviolet-induced erythema: a human study in vivo. Br J Dermatol 1998;139:332-339.  (PubMed)

Geesin JC, Darr D, Kaufman R, Murad S, Pinnell SR. Ascorbic acid specifically increases type I and type III procollagen messenger RNA levels in human skin fibroblast. J Invest Dermatol 1988;90:420-424.  (PubMed)

Linus Pauling Institute. 2017. Vitamin C and Skin Health | Linus Pauling Institute | Oregon State University . [ONLINE] Available at: http://lpi.oregonstate.edu/mic/health-disease/skin-health/vitamin-C.

Ou-Yang H, Stamatas G, Saliou C, Kollias N. A chemiluminescence study of UVA-induced oxidative stress in human skin in vivo. J Invest Dermatol 2004;122:1020-1029.  (PubMed)

Pinnell SR, Yang H, Omar M, et al. Topical L-ascorbic acid: percutaneous absorption studies. Dermatol Surg 2001;27:137-142.  (PubMed)

 

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