1. Vitamin C serum can and will act as a pro-oxidant, causing skin damage
A pro-oxidant is the opposite of an antioxidant. Where an anti-oxidant is a molecule that prevents oxidation of other molecules, and hence protects against the cell-damaging effects of free radical production, a pro-oxidant does the reverse, and induces oxidative stress, either by generating reactive oxygen species or by inhibiting antioxidant systems.
Vitamin C on its own is an anti-oxidant. So when you eat foods high in vitamin C, you get the health benefit of the vitamin donating electrons, and thus preventing oxidation of tissue, lipids, protein, and DNA.
Vitamin C's ability to readily donate electrons, and thus acting as an anti-oxidant also means that it readily reacts with other molecules, which has consequences that aren't always good. In the presence of catalytic metals, vitamin C reacts with those metals causing a pro-oxidant effects, specifically, vitamin C reacts with oxygen, producing superoxide that subsequently dismutes to produce harmful by-products such as hydrogen peroxide (H2O2). Furthermore, it requires little vitamin C to have it act as a pro-oxidant, and a lot of vitamin C to act as an anti-oxidant.
The Fenton Reaction causes vitamin C to act as a pro-oxidant
The Fenton Reaction causes vitamin C to act as a pro-oxidant
When vitamin C acts as a pro-oxidant, the consequences include irritation, inflammation, collagen and elastin breakdown, and acne. So if you have any of these skin ailments, and are using a vitamin C serum, then its time to re-think your regimen.
Vitamin C's propensity to become a pro-oxidant when in contact with metal is concerning from a skin-care standpoint because the metals vitamin C react with are metals our skin encounters often. When vitamin C encounters iron a biological reaction, known as the Fenton reaction, is initiated. The Fenton reaction is the pivotal reaction in the oxidation of membrane lipids and amino acids, and in the reactions where biological reduction agents are present, such as vitamin C. Our skin comes into contact with iron every day. According to the FDA, iron is a significant pollutant in the air and in the water, and from recent research from the University of Birmingham: "Human activities may have led to an increase of atmospherically soluble iron in the oceans by several times since the Industrial Revolution."
When we topically apply vitamin C to our skin, and our skin comes in contact with the air, which contains iron due to pollution, we are inviting a pro-oxidant reaction to occur. It is also safe to assume that since water contains iron contaminants, in general, that much of the water used in your skin care contains iron too. There is no way around iron pollution coming in contact with your skin. Your best safeguard to minimize harm is to avoid molecules that interact with iron to form damaging pro-oxidants.
2. Vitamin C reacts with common compounds found in cosmetics.
Piggybacking on point #1, we can say that many compounds found in cosmetics are further eliciting vitamin C to become a pro-oxidant. Let’s, for the sake of brevity, just take 3 common ingredients found in cosmetics:
1. EDTA
EDTA is a common preservative used in food, household cleaners, laboratory specimens, and in cosmetics. EDTA contains 9.7-19.4 uM of iron per 50mM sample, which is enough to elicit the Fenton reaction described above.
EDTA prevents blood from coagulating, and is used to preserve to laboratory specimens.
EDTA prevents blood from coagulating, and is used to preserve to laboratory specimens.
2. Copper
Copper is another ingredient that has generated a lot of buzz as of late because of research that has found some anti-aging effects when topically applied. The concern with combining copper and vitamin C is greater (by some research) than combining iron with vitamin C. From Buettner and Jurkiewicz:
“But because copper is -80 times more efficient as a catalyst for ascorbate oxidation than iron, in typical phosphate buffers it is the adventitious copper that is the biggest culprit in catalyzing ascorbate oxidation.”
So although copper is not something you are likely to encounter every day in terms of environmental contaminants, the likelihood of it being in your cosmetics (including skin care) is becoming greater due to it’s increasing popularity as an anti-aging ingredient. And this is cause for concern given that it has a stronger effect on turning vitamin C into a pro-oxidant than iron.
3. Phosphates
Phosphates are everywhere in cosmetics, from haircare, to foundations and primers, to cleansers, and have a multitude of functions, including balancing the pH of a formula, emulsifying water and oil ingredients, and enhancing the lathering effect of a product. On their own they are fairly harmless, although for some they can be drying to the skin and hair. However, phosphates contain both trace sources of iron and copper, both of which elicit a pro-oxidant reaction from vitamin C.
Getting vitamin C from food is your best bet for optimal skin health
Getting vitamin C from food is your best bet for optimal skin health
3. Tachyphylaxis and your skin not reacting to skin care when you really need it to.
Tachyphylaxis is a word you probably never heard of before, but I am sure you are familiar with the phenomenon. If you ever had to use a certain medication long-term you may have noticed that the effects were most pronounced in the beginning, and waned over several months of use. One reason why the effects of pharmaceuticals don’t last over the long-term (with certain exceptions) is because the receptors on our cell’s surface become desensitized over time, inhibiting the drug’s effectiveness biologically.
Vitamin C serums are used to promote collagen synthesis (or at least that’s what is among the most common reasons for it being used in anti-aging skin care), and my hypothesis is that using a vitamin C serum too early in one’s life will make your body less inclined to have the positive skin benefits later on when you really need it.
When you are under the age of about 45, your body is still producing collagen on its own. With some exceptions, if you drink, smoke, or go outside without adequate UV protection you are causing the degradation of collagen, but let’s ignore those factors for the sake of this argument. If you are using a skin care supplement, such as a vitamin C serum when you are in your 20s, or 30s, when your body is already producing collagen, what is stopping tachyphylaxis from occurring? And let’s say you have been using a vitamin C serum to promote collagen (when your body is already naturally doing it on its own) for 20 years, you're 45-50 years old and your body is not producing collagen any more. Do you really think that vitamin C serum is going to have any effect now? It is like having a loaded firearm and firing all of your bullets as a warning shot. When the threat actually arrives you won’t have any bullets left to protect yourself.
Ironically, vitamin C serums can cause the breakdown of collagen, acting as a pro-aging agent when in contact with compounds that cause it to act as a pro-oxidant
Nowadays with youth-obsessed culture we go to the top-shelf of our skin care right away. I’m not saying that vitamin C serums are “top shelf” as in they are a holy grail. They’re not. They’re a gimmick at best. I am saying we go to extreme measures (which are usually gimmicky and dangerous) right away before we need them, if we ever truly need them, because people nowadays are told via advertising and marketing that wrinkles are bad. They’re not. In my experience, a person with a few wrinkles atop healthy skin looks magnitudes better than a person with taut, damaged skin from facelifts, chemical peels, and other harsh measures.
My conclusion from vitamin C serums is that they are the product of viral marketing, and are a gimmick at best and a cytotoxic agent at their worst. Why risk your skin’s health for something that we will probably all cradle our face in our hands 20 years from now at the very thought of using? If you are concerned about collagen growth, use a daily chemical exfoliant. If you are just looking for a proper skin care regimen, then just use a serum that has been heavily researched with a balance of healthy oils and extracts. And my final word is that skin care is just like every other industry out there, and every industry is just looking for the latest and greatest way to take your money. Today it’s vitamin C, tomorrow, who knows.
*BONUS*
4. Vitamin C Serums Cause Acne in Healthy Skin
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Updated finding
December 23rd, 2018
Read the updated finding on how vitamin C serums disrupt a healthy skin microbiome and cause acne here
Followup Investigation Below
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May 22, 2018
Read our Followup investigation on Vitamin C Serums
References:
Buettner, G. R., & Jurkiewicz, B. A. (1996). Catalytic metals, ascorbate and free radicals: combinations to avoid. Radiation research, 145(5), 532-541. Chicago.
Ceolin, V., Ghia, C. (2014). The Fenton Reaction: pro-oxydant role of vitamin C. <http://flipper.diff.org/app/pathways/6861> Accessed November 30, 2017.
du Vivier, A., & Stoughton, R. B. (1975). Tachyphylaxis to the action of topically applied corticosteroids. Archives of Dermatology, 111(5), 581-583.
Sullivan, R. J. (1969). Air pollution aspects of iron and its compounds.
Weijun Li, Liang Xu, Xiaohuan Liu, Jianchao Zhang, Yangting Lin, Xiaohong Yao, Huiwang Gao, Daizhou Zhang, Jianmin Chen, Wenxing Wang, Roy M. Harrison, Xiaoye Zhang, Longyi Shao, Pingqing Fu, Athanasios Nenes, Zongbo Shi. Air pollution–aerosol interactions produce more bioavailable iron for ocean ecosystems. Science Advances, 2017; 3 (3): e1601749 DOI: 10.1126/sciadv.1601749
Wendy O
November 30, 2017
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