The Ingredient of the Week is ascorbic acid, also known as Vitamin C.
L-ascorbic acid (Vitamin C) |
(For earlier discussions of Vitamin C, see here and here.)
Ascorbic acid occurs naturally in both plants and animals, but humans lack the ability to synthesize it so it must be obtained through our diet. Ascorbic acid is required for numerous biochemical pathways in the human body, including the biosynthesis of collagen, which is an important structural component of connective and epithelial tissue (which includes skin). A deficiency in Vitamin C gives rise to scurvy, a potentially fatal disease if not treated in time.
James Lind, a Scottish physician who carried out some of the first recorded clinical experiments, showing that citrus fruits could be used to treat and prevent scurvy. |
Oxidation of ascorbic acid; last step carried out in the presence of a metal ion, in this case silver (Ag+). |
One way to preserve the activity of Vitamin C is to combine it with other antioxidants, the idea being that the presence of other antioxidants will compete for reaction with free radicals. An example of such an antioxidant is Vitamin E (also known as tocopherol).
alpha-Tocopherol (Vitamin E) |
Cross section of epidermis |
Cellex-C High Potency Serum (see below for ingredient list) is the original Vitamin C serum, introduced in 1994. It is a straightforward formulation of 10% ascorbic acid in water, along with acetyl tyrosine (an amino acid), zinc sulfate, sodium hyaluronate, and bioflavanoids derived from green tea (Camellia sinensis). It is free of any extraneous ingredients: it is fragrance- and colorant-free, as well as being free of preservatives.
Cellex-C High Potency Serum (available in Toronto at The Anti-Aging Store) |
Dr. Lisa Kellett is a well-known dermatologist based in Toronto. Along with a cosmetic dermatology practice, she also has her own skin care line. Thanks to Helen Vong, editor-in-chief of TheSkiny.com, I got the chance to review Dr. Kellett's Topical Vitamin C Ferulic Serum (see below for ingredient list).
Kellett Topical Vitamin C Ferulic Serum (available in Toronto at DLK on Avenue; also available online HERE) |
The form of Vitamin C found in the Kellett serum is tetrahexyldecyl ascorbate, which is an oil-soluble derivative of ascorbic acid. As tetrahexyldecyl ascorbate is oil-soluble, it can penetrate the skin much more readily than ascorbic acid. According to the formulators of this serum, tetrahexyldecyl ascorbate penetrates the skin three times higher than ascorbic acid, when both are applied at the same concentration. The Kellett serum contains additional antioxidants, Vitamin E (tocopherol), green tea extract, and ethylhexyl ferulate (an oil-soluble form of ferulic acid, a plant-derived antioxidant). The combination of antioxidants acts to stabilize each other and thus increase their overall effectiveness, as well as increase the shelf-life and stability of the formulation.
Finally, the Kellett serum contains tridecyl salicylate, an oil-soluble derivative of salicylic acid, a chemical exfoliant which serves to further refine skin texture. It is free of fragrance, colorants, and preservatives.
The Kellett serum is comparable to SkinCeuticals C+E Ferulic Skin Serum (see earlier review here). Although the Kellett serum comes with instructions to apply every other night, I decided to follow the same regimen as with the SkinCeuticals serum, i.e. applying in the morning, followed by SPF 30 sunscreen over top, before heading out for the day, the idea being to use the antioxidants in the serum to protect skin against oxidative damage from environmental exposure during the course of the day. However, due to the presence of the salicylate, those with sensitive skin should stick with applying the serum at night, and be sure to wear sunscreen during the day.
Because this is a silicone solution, it is appears as a very thin, oily liquid that absorbs quickly with a very fast dry-down, so you have to spread very quickly before it absorbs. When I first started using this, I used about 5 drops, but found that after about a week of this regimen, I started to break out and I was getting a lot of plugged pores. From long experience, I know that silicone-based formulations don't work well on my oilier, stress-prone skin type, and so I was not surprised that I had this initial reaction to the Kellett serum. (Besides the breakouts, too much of it makes my skin feel uncomfortable and slightly itchy.) I cut back to 2-3 drops per application, working quickly to apply a very thin film, and that has worked out better for me - no breakouts and far fewer plugged pores. If you have a similar issue with silicone-based formulations, I think the key to this one is to apply very sparingly.
The Kellett serum definitely helps to boost radiance and to refine skin texture. Unlike the Cellex-C serum, the Kellett serum is colourless. More importantly, it does not appear to change colour over time, and it does not need to be refrigerated. The Kellett serum has almost no odour at all, a big plus compared to the SkinCeuticals serum, which had a strong, unpleasant odour of amines, similar to uncooked hotdogs. This serum is recommended for its ease of use, and its anti-ageing and skin-protective effects.
*In this review: Cellex-C High Potency Serum was purchased by me; Kellett Topical Vitamin C Ferulic Serum courtesy of TheSkiny.Com and DLK on Avenue. Thank you to Helen Vong, editor-in-chief of TheSkiny.Com for the opportunity to review the Kellett serum. This review is cross-posted to TheSkiny.Com, an e-magazine dedicated to the latest in beauty and dermatology - please check it out here!
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IngredientsCellex-C High Potency Serum: water, ascorbic acid, acetyl tyrosine, zinc sulfate, sodium hyaluronate, bioflavanoids (from Camellia sinensis).
Kellett Topical Vitamin C Ferulic Serum: cyclomethicone, tetrahexyldecyl ascorbate, tridecyl salicylate, dimethiconol, hexyldecanol, bisabolol, cetyl cetyl hydroxyproline palmitate, stearic acid, rapeseed sterols, tocopherol, ethylhexyl ferulate, Camellia oleifera (green tea) extract.
I love vitamin c
ReplyDeleteCan I have some more please?
ReplyDeleteLet's eat bacon.
ReplyDeleteHow about a chicken mc nugget?
ReplyDelete