The Scientific Papers Supporting Vitamin C Serum's Skin Benefits are Flawed
The Scientific Papers Supporting Vitamin C Serum's Skin Benefits are Flawed
by Wendy Ouriel
At OUMERE Labs™ we spend half our time on skin care. The other half is spent on age-reversing biological research. And in the months since the Vitamin C article was published I have been working on gathering additional support for my hypothesis that the widely regarded ingredient does more harm than good.
One of the issues with the research supporting vitamin C as an anti-aging ingredient is the lack of negative data. Specifically, there are no follow-up papers discussing how vitamin C does not promote collagen production. And this is is a problem. To a layperson not in the sciences, it would be assumed that the lack of negative data is a good thing because this means the results are conclusive. When I see a lack of negative data, especially for a research topic that is popular and a cosmetic cash cow, I see a red flag. A lack of negative data on a widely researched topic means biased, incomplete science. It means there has been no study trying to reproduce the data obtained from the original study. Without reproducibility you do not have science, and the results of irreproducible research are fools gold.
Science does not prove anything. Only a court of law can do that. Science merely refutes or supports existing hypotheses.
Nothing in biology is concrete or conclusive. You can take something as clear cut as the link between second-hand smoking and lung cancer, and find studies that have convincing support that breathing in another’s cigarette smoke does not increase their chances of developing lung cancer. So when I cannot find, among a mountain of research lauding the skin benefits of topical vitamin C for skin health, a single paper that says this may not be the case, or even discusses the basic pro-oxidant reactivity of vitamin C when topically applied, I am suspicious.
A lack of negative data means a lack of scientific investigation
I am even more suspicious about the lack of studies showing the skin-damaging effects of vitamin C because in the months since I have published the original vitamin C article, I have received countless e-mails from readers saying that after reading my report, they decided to forgo their vitamin C serums. And after one to two weeks, their rosacea, skin inflammation, acne and sensitivity had cleared up.
A Proper Analysis of the Data
I spent 10 years learning how to properly read, analyze and compose scientific research. Specifically biological research. And even more specifically, cellular biological research. A two page scientific paper takes me a week to read because I am analyzing everything:
- The sources the paper cited- are they from credible journals? Is the research sound? Does the research support the citing authors statements?
- The introduction of the paper- What is the starting point for this research? Do the authors show a good background knowledge of the subject matter? Has this research been done before, and if so, why are the authors repeating it?
- The methods- This part takes the longest for me to read, because it is the most important. Methodology is the most fundamental part of any research paper because it shows whether or not the paper has any validity. Did the authors use the right stains? Did the authors use the right kind of microscope? What about the right magnification to observe their samples? What about tissue preparation? Were the right fixatives used? There are countless questions to be asked, and you only know to ask these questions if you have done similar research yourself. Thus necessitating a educational and research background in the paper from which you are reading.
- The results- I have found more fiction in the results section of some scientific papers than in the Mystery section of Barnes and Noble. The results section shows what the authors found as a result of their methods. Did the authors include all necessary figures to support their conclusion? Are the figures clear? Am I seeing enough data to support the authors hypothesis?
- The conclusion- This is where the authors sum up and interpret their results. Do the authors have strong support for their conclusion? Or are big assumptions made from the results? Do the authors admit any gaps still in the research? What are the next steps to be made?
Something key to note is that for all of the above mentioned points, I can only determine the answers to my questions by having a background in biology. There is no way, if I were a chemist, a physicist, or a beauty blogger I could determine if a biological research paper had merit. A chemist cannot look at a piece of cellular biological research, look over the methods, and determine if the researchers used the proper tissue stain for their study. And if the wrong stain is used, the results are a charade. A physicist or a beauty blogger has no life science research background, therefore they cannot properly analyze a scientific paper. They cannot determine if the sources cited support the authors claims, they cannot analyze the methods and determine if the proper steps were taken for the authors to conduct their research, and if the results are a true and accurate depiction of the natural world. And they cannot replicate these experiments, or have the background to understand why replication is necessary, or even question its value in the first place.
Consider the source, and when you read a blog article next time, ask yourself if the person citing scientific studies sat down and did the proper analysis, as described above, or did they just read the summary and then summarize the summary to you?
The reason why misinformation is rampant in skin care is because scientific research papers are now available to everyone. The problem is that they weren’t written for the general public. And when the general public reads scientific research, they provide their own interpretation, which is usually an inaccurate representation of the authors conclusions. This results in the spreading of misinformation, and bad science being passed off as sound science just by mere fact that it was written by someone wearing a white lab coat. The general public does not have a 10 year+ background in the authors subject matter, and the result of a layperson reading scientific research that they have no understanding of or background in, is misinformation that gets carried on to the commercial phase. And from the misreading of scientific papers about vitamin C and collagen, you get the vitamin C serum fad we have today. And damaged skin as a result.
There is a right way and a wrong way to read and use scientific literature
The right way to read scientific literature is carefully, slowly, and thoroughly. You are an investigator who is tasked with determining the validity of the research. You come into the paper not searching for specific answers, but rather for a deeper understanding of the natural world.
The right way to use scientific literature is as a piece of an overall puzzle in your investigation of the natural world.
The wrong way to read scientific literature is quickly, looking for points that coincide with your biases, and using only those points in your arguments.
The wrong way to use scientific literature is as a brick in the wall of your opinion.
In the time since I published my original vitamin C article, I have been working on replicating some of the key papers that stated that topical vitamin C up-regulates collagen in skin. But before I replicated any experiments, I researched the top-cited vitamin C papers for validity. And I found many problems.
The methods for the top cited papers were flawed.
- Improper histological techniques. Tissue samples were not fixed properly, and therefore any data obtained is not an accurate depiction of natural phenomenon. For example, Haftek et al. (2008) makes no mention of dehydration of their tissue after fixation for paraffin embedding. Failing to do so will provide inaccurate data. Furthermore, the study does not detail how the tissues were processed for paraffin embedding, which opens the possibility that improper techniques were used, which can damage the tissue and lead into an artifact
- Sample sizes are too small to be an accurate reflection of the population. Murad et al. (1981) uses a sample size of 1, Humbert et al. (2003) and Haftek et al. (2008) uses a sample size of 20. Nusgens et al. (2001) and Fitzpatrick and Rostan (2002) uses a sample size of 10. * To put the importance of a sample size into perspective. If you were very sick, and needed a new kind of drug, or even a drug that has been around for a while, would you trust a drug that was tested on 10 people? What about one person? Or would you want to see it tested on thousands before you decide to take it for your health?
- Studies were conducted on non-human skin , or skin cells in a dish. Which is not an indication that the same effects will be seen in human models. Lin et al. (2003) Boyera, , Darr et al. (1992), Galey and Bernard (1997), Haha and Senoo (1989)
- Studies were only measuring effects that occurred over a few days or weeks. And made assumptions of long-term effects. Lin et al. (2003), Tajuma and Pinnell (1982)
- Studies are conducted on people who may be deficient in vitamin C. Vitamin C deficiency is a common worldwide phenomenon (Carr et al. 2016, Ravindran et al. 2011, Tveden-Nyborg, P., & Lykkesfeldt, J. 2013) and is especially common among those of older age, and many of the subjects of vitamin C studies are post-menopausal women . Therefore the up regulation in collagen is more the result of their body returning to a normal amount of collagen production. Not the body suddenly making more collagen as a result of topically applying vitamin C, where it otherwise would have produced no collagen on a healthy individual. None of the studies discuss giving a blood test to their subjects beforehand to ensure that they had adequate vitamin C levels prior to the study. Nusgens et al. (2001), Humbert et al. (2003), Haha and Senoo (1989)
- The laboratory environment does not mimic how one would use vitamin C serum at home, or in normal cosmetic usage. For example, Boyera, Galey and Bernard (1997) wrapped their vitamin C cultures in aluminum “to protect compounds from light.” The reason for which is vitamin C’s propensity to rapidly oxidize. When vitamin C is sold commercially, it is exposed to light, even when in an amber container. And when you put it on your skin, you are exposing it to light, further inflating the deleterious, pro-oxidant effects caused by vitamin C, and the resulting oxidation that occurs from light exposure.
- Dubious results section. Graphs are shown, but no actual tissue samples, which opens the door for false reporting of results by fabrication of data. Hate and Senoo (1989), Murad et al. (1981). Or results are shown, but the data does not show what the authors claim. For example, Haftek et al (2008) in their Figure 2 shows a control and tissue after treatment with Vitamin C. I see no difference between the amount of collagen bundles in the control and the vitamin C-treated sample.
- Improper controls: Fitzpatrick and Rostan (2002) assess their subjects for wrinkles, then put a vitamin C serum containing ‘an anhydrous polysilicone gel base’ onto the skin. This will sit into the wrinkles of their patients, and make it appear as though wrinkle reduction has occurred. But all that has happened it the wrinkles were covered up. Furthermore, the study does not control for the skin dryness of patients, which when hydrated by the gel base, will cause wrinkles to be less prominent. And is not a result of up regulation of collagen by the vitamin C serum.
- Improper assessment of test subjects: Wrinkles are measured by researcher on a scale of 1-10, and not by use of specific equipment. Researchers had to rely on a visual measurement. Measuring wrinkles by visual assessment is a highly subjective, varies from person to person, and not reliable (Haftek et al 2008). Patients were tasked with assessing their skin dryness prior to the study, and was not backed up by any research methods (Haftek et al. 2008).
There is a conflict of interest. Studies supporting the benefits of vitamin C serums are funded by the companies that make vitamin C serums
1. Nusgens et al.(2001), Haftek et al. (2008) and Humbert et al. (2003) found that the use of a vitamin C serum enhances collagen stimulation. Supplier of the vitamin C serum: La Roche Posay. Funding of the studies provided by: La Roche Posay.
2.. Boyera, Galey and Bernard (1997), Marionnet et al. (2006) papers on the collagen benefit of topical vitamin C is funded by L’Oreal.
Important findings that refute the author’s hypothesis (or nullify it) are buried in the literature
1. The placebo or control’s values are very close to the values obtained from the experimental variable. Humbert et al. (2003)
2.. The cytotoxicxicity of vitamin C, and resultant cell death experienced by the cells being studied. Boyera et al. (1997).
3. The failure of vitamin C to remove wrinkles on certain areas of the face. Haftek et al. (2008)
I always go into a scientific study assuming the opposite of what the authors say is true, and the onus is on them to convince me otherwise. If I read a paper that states that the sky is blue, I am going to go in assuming it's red. A strong scientific study is written authors with a profound background in the subject matter, has detailed, accurate and highly thorough methods. Results that are a clear and accurate depiction of the variables being measured. Conclusions that properly summarize and assess the results, and a reference section that solidifies the research that went into the study. I do not see any such thing with the above cited vitamin C studies. And the lack of convincing support is troubling considering that these papers are among the most highly cited.
The problem with the vitamin C studies is that the researchers were given a result, and looked for data to confirm that result, while ignoring all refuting evidence. It is bad science.
I am working on replicating some of the above mentioned studies to determine if I achieve the same results, and will follow up in an upcoming post. Stay tuned.
Darr, D., Combs, S., Dunston, S., Manning, T., & Pinnell, S. (1992). Topical vitamin C protects porcine skin from ultraviolet radiation‐induced damage. British Journal of Dermatology, 127(3), 247-253.
Haftek, M., Mac‐Mary, S., Bitoux, M. A. L., Creidi, P., Seité, S., Rougier, A., & Humbert, P. (2008). Clinical, biometric and structural evaluation of the long‐term effects of a topical treatment with ascorbic acid and madecassoside in photoaged human skin. Experimental dermatology, 17(11), 946-952.
Humbert, P. G., Haftek, M., Creidi, P., Lapière, C., Nusgens, B., Richard, A., ... & Zahouani, H. (2003). Topical ascorbic acid on photoaged skin. Clinical, topographical and ultrastructural evaluation: double‐blind study vs. placebo. Experimental Dermatology, 12(3), 237-244.
Lin, J. Y., Selim, M. A., Shea, C. R., Grichnik, J. M., Omar, M. M., Monteiro-Riviere, N. A., & Pinnell, S. R. (2003). UV photoprotection by combination topical antioxidants vitamin C and vitamin E. Journal of the American Academy of Dermatology, 48(6), 866-874.
Marionnet, C., Vioux‐Chagnoleau, C., Pierrard, C., Sok, J., Asselineau, D., & Bernerd, F. (2006). Morphogenesis of dermal–epidermal junction in a model of reconstructed skin: beneficial effects of vitamin C. Experimental dermatology, 15(8), 625-633.
Murad, S., Grove, D., Lindberg, K. A., Reynolds, G., Sivarajah, A., & Pinnell, S. R. (1981). Regulation of collagen synthesis by ascorbic acid. Proceedings of the National Academy of Sciences, 78(5), 2879-2882.
Nusgens, B. V., Colige, A. C., Lambert, C. A., Lapière, C. M., Humbert, P., Rougier, A., ... & Creidi, P. (2001). Topically Applied Vitamin C Enhances the mRNA Level of Collagens I and III, Their Processing Enzymes and Tissue Inhibitor of Matrix Metalloproteinase 1 in the Human Dermis1. Journal of Investigative Dermatology, 116(6), 853-859.
Ravindran, R. D., Vashist, P., Gupta, S. K., Young, I. S., Maraini, G., Camparini, M., ... & Ravilla, T. D. (2011). Prevalence and risk factors for vitamin C deficiency in north and south India: a two centre population based study in people aged 60 years and over. PLoS One, 6(12), e28588.
Tajima, S., & Pinnell, S. R. (1982). Regulation of collagen synthesis by ascorbic acid. Ascorbic acid increases type I procollagen mRNA. Biochemical and biophysical research communications, 106(2), 632-637.
Tveden-Nyborg, P., & Lykkesfeldt, J. (2013). Does vitamin C deficiency increase lifestyle-associated vascular disease progression? Evidence based on experimental and clinical studies. Antioxidants & redox signaling, 19(17), 2084-2104.