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L-Ascorbic acid content in Vitamin C serum
I was told by a technical rep of an ingredient company that 10% L-ascorbic acid is to high for a serum and will cause “burning” in people with sensitive skin. I’ve seen that most products in the market contain at least 10% and haven’t seen any warnings about potential irritation or burning.
I will appreciate some input on this. Thank you in advance. -
4 Replies
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The irritancy will depend more than pH than the concentration of vitamin C.
A solution with 20% of vitamin C at pH 5.5 may be less irritant than a solution with 10% of vitamin C at a pH 2.5 for instance.Anyway, it’s believed is necessary a pH below 4 to achieve a optimum penetration of vitamin C.SkinCeuticals (L’oréal) for instance offers a solution with 15% of vitamin C in a pH about 3.5. -
Just be aware that high concentrations of ascorbic acid will turn your serum yellow/brown after a few short months. Also the more you use the more the product will have a sticky feel while it is drying. That being said, 15% to 20% is very common.
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Generally when they claim a high level of Vitamin C (I call it chasing the Perricone dragon) they are using a more stable form of Vitamin C. L-Ascorbic acid is a HUGELY flawed Cosmetic active in the fact that in an aqueous product you will have oxidation and hence browning unless you can isolate the product (many ways). For water based Vitamon C look at Sodium Ascorbyl Phosphate or Magnesium Ascorbyl Phosphate. For the lipid phase you have Ascorbyl Palmitate or many other forms.
Unfortunately I have seen products imply that 1 part Ascorbyl Phosphate equals 1 part Ascorbic acid. This is not true.
It is common to see these products used that high. But in my experience I see that the Vitamin C certainly peaks in activity at much lower levels. In many cases they lose the advantage of using other actives as well when they “chase the Perricone Dragon.” -
Thank you all for your input. I was planing to avoid the oxidation issue by using an anhydrous system made with 100% silicone, but apparently the concept is protected with a patent. So, I think I will explore Mark’s suggestion on using other stable forms of ascorbic acid in a water system. Besides, silicone gel is expensive. Thanks again. Ruben
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