Why Vitamin C Serums Should Never Exceed 20% in Strength

There are a lot of superb vitamin c serums out there. I honestly probably only know of 50% of them, and I seem to learn about new ones all the time. Most of the pure L-ascorbic acid serums are highly effective. However I should point out some things to look for -particularly concerning the strength of the serums.

Dermatologists all agree that vitamin c has several skin benefits that go beyond skin lightening. One thing that is crucial for the l-ascorbic acid to actually be of use is both the pH level and concentration. L-ascorbic acid must be at pH levels of 3.5 to penetrate the skin. Also, serums should never exceed 20% since the skin can only absorb 20% to saturate the tissues. It should be noted that 20% is quite strong, so when I stumble across vitamin c serums that are 22%-30% L-ascorbic acid it really leaves me perplexed.

So what happens when you do apply a vitamin c serum that is beyond 20%? Well according to a study focusing on L-ascorbic acid’s percutaneous absorption levels, the skin only absorbs the 20%. In some cases, the skin ceases to absorb very little L-ascorbic acid in the tissues altogether, so in essence the efficacy is compromised in high level vitamin c serums.

Avoid using vitamin c serums that go beyond 20%. If you have sensitive skin, stick to 10%. If you have built tolerance to vitamin c serums overtime, then opt for 15-20% concentrations.

I highly recommend you to take at look at this study. I learned a great deal about vitamin c from it:

http://www.nordicselfcare.com/pdf/1.09_percutaneousabsorption.pdf