Vitamin C in Cosmetic Products – Does it work? episode 211

It’s an all Vitamin C podcast episode. In this show we answer questions including…

Beauty Questions

  • Are there different grades of vitamin C/ascorbic acid since the prices vary so much for the same thing?
  • What is your opinion of the effectiveness of waterless Vitamin C products?
  • Does Vitamin C really do anything for your skin?
  • Is it ok to use jars for packaging?

Vitamin C in Cosmetics

Alright, let’s move on to the main show topic, Vitamin C!  Now, Randy and I covered the topic way back in episode 31, but I thought it was time to revisit it.  This is an ingredient that gets lots of positive press. A quick look through Google Trends finds that it has been steadily gaining interest in the last ten years. Right now it is about on the same level as another popular topic, CBD. We’ll save that for another show. Let’s look at Vitamin C.

Vitamin C is a chemical called ascorbic acid that has a wide variety of functions in our body, most notably as an antioxidant. It is not naturally produced in our bodies so we need to get it from our diet. Fortunately, a lot of foods we eat either have vitamin C in them or they are fortified with it.

Vitamin C is known to play a role in collagen production in the skin. Additionally, when topically applied it is thought to help heal acne, increase skin barrier function which reduced moisture loss, protects from UV radiation, and prevent & lightens age spots.

So, it sounds like a great ingredient! Which is why you see it in a lot of skin care products and it’s raved about on beauty blogs. Of course, there is a downside – It’s an antioxidant that is highly reactive with oxygen in the air and water so it’s difficult to deliver vitamin C to your skin in a way that is stable, effective and non-irritating.

For this reason raw materials companies have come out with a bunch of different forms of vitamin C. They modify the basic ascorbic acid structure in the hopes of making it more stable but still delivering some benefit. So let’s talk about how successful that is or not.

Types of Vitamin C

First, the types of vitamin C out there. There are a bunch including

Ascorbic Acid (AA) and more specifically, L-Ascorbic acid. The L just refers to the handedness of the molecule. This has to do with chirality and where specific atoms are on the molecule but suffice it to say, L-ascorbic acid is the more active version than D-ascorbic acid.

Other types you might see in cosmetics include Sodium Ascorbyl Phosphate (SAP)
Magnesium Ascorbyl Phosphate (MAP)
Ascorbyl 6-Palmitate (AA-PAL)
Ascorbyl Tetra-Isopalmitate (VC-IP)
Ascorbyl Glucoside (AA-2G)
Dehydroascorbic acid

Now, the ingredient that is biologically active is Ascorbic Acid. So, these other versions need to penetrate the skin and then get converted to ascorbic acid to be effective. Well, in a study published in Dermatologic Surgery back in 2001 looking at this exact question, none of the derivatives significantly converted to L-ascorbic acid in the skin. There is some evidence that they might convert but this is pretty weak. So, while they might be more stable in the formula and penetrate better, they probably aren’t actually working. At least in the way ascorbic acid works.

So let’s talk about Ascorbic Acid (AA) Most importantly in a formula, if it’s going to work, it has to be stable which means it has to chemically exist as ascorbic acid in the formula, and it has to penetrate the skin to get to the Dermis which is where all the skin activity happens.

So, is it stable? Well, researchers have found that it is stable at pH less than 3.5 in aqueous solution and it’s stable in anhydrous systems. So, if your product has a pH higher than 3.5, you’re probably not getting working vitamin C. Unless, it’s waterless.

Based on available research, ascorbic acid is the gold standard for Vitamin C. For it to do anything significant, it needs to be included in a formula in a concentration higher than eight percent. Now studies have shown that above 20 percent there isn’t much more biological significance so it looks like the sweet spot for vitamin C in a formula is between 10 and 20 percent. Effectiveness of course will vary based on the formulation.

I’ll also give our usual disclaimer about these types of cosmeceutical ingredients. If this ingredient was actually working as claimed, (you know affecting collagen synthesis, anti-acne, reducing UV damage, etc.) it would technically be an illegal drug. In the US anyway. Cosmetics are not allowed to do those things. But if companies don’t make specific drug claims, the FDA usually doesn’t go after them. At least, at the moment.

So some things to consider when looking at products that advertise they use vitamin C.

First – Look for something that uses ascorbic acid. It’s the ingredient that works. The derivatives haven’t really been proven to work.

Next, look for products that use ascorbic acid in levels between 10 – 20 percent. Most companies don’t tell you how much they use but when they do (assuming they aren’t lying) that’s what you should look for. Under 10% it’s probably not doing much and over 20% doesn’t do much extra but it can lead to irritation.

Another tip – waterless products are probably going to be more effective.
AA can begin to oxide (which causes it to be used up) as soon as it’s dissolved in water. Look for products where water is NOT one of the first ingredients. That gives you a better chance of finding a product that will really work. That means looks for serums instead of cream based products.

Also, if you are getting a water based product look for something that has a low pH. As I said AA is unstable above 3.5 or so. Look for low pH products. Of course pH is only meaningful if water is present so it’s less of an issue in the kinds of water free formulas we just discussed.

Finally, consider the packaging the product is in. Any Vitamin C formula must be properly packaged to protect it from excess light and air. So pump packaging is probably better and you should avoid things that are clear as light can degrade the ingredient. Look for brown glass containers.


Question 1 – Mei asks – From Kielhs to clinique to the ordinary. Is there different grades of vitamin C/ascorbic acid since the prices varies so much for the same thing. I understand some vit c serum contain other actives thus making it more expensive. Ignoring that, is there a difference in the ascorbic acid these various brands us?  For example, i think mineral oil come in diff grades ie. Cosmetic grade and pharmaceutical grade.

Question 2 – Katherine says – I listened to your most recent podcast and I was wondering what your opinion is of the effectiveness of these 2 Waterless Vitamin C products from The Ordinary.

Vitamin C Suspension 23% + HA Spheres 2%  Ingredients: Ascorbic Acid, Squalane, Isodecyl Neopentanoate, Isononyl Isononanoate, Coconut Alkanes, Ethylene/Propylene/Styrene Copolymer, Ethylhexyl Palmitate, Silica Dimethyl Silylate, Sodium Hyaluronate, Glucomannan, Coco-Caprylate/Caprate, Butylene/Ethylene/Styrene Copolymer, Acrylates/Ethylhexyl Acrylate Crosspolymer, Trihydroxystearin, BHT.

Vitamin C Suspension 30% in Silicone  Ingredients: Dimethicone, Ascorbic Acid, Polysilicone-11, PEG-10 Dimethicone.

Question 3 – This one comes to us from Ashley.  She asks – When using vitamin c, does it actually affect the skin in a positive way? The claim is that is “lightens, tightens, and brightens” the skin. Typically products start at 8% vitamin and go up to 20%. After getting up to 20% you’re supposed to start back at 8% because your skin will get used to it. How does any of this work? 

Question 4What’s the scoop on products that are in jars? Don’t they get exposed to air  when on skin? What about contamination? Is it true  for facial products or products for  the body?

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