Vitamin C serums are not skin care, they're sales.

I have been studying skincare for a decade, and biology for much longer. My expertise lies in cellular biology, with a specific focus on extracellular matrix biology. I’ve conducted research in university laboratories, designed and executed my own experiments in a lab I built, and now I run a skincare company informed by this scientific foundation. With this background, I can confidently state that I am an expert in skincare biology. To my knowledge, I am the only individual in the skincare industry who both owns a company and conducts independent, science-driven experiments to evaluate skincare claims.

I didn’t set out to become a skincare investigator—it happened naturally about ten years ago when my skin was damaged by poor skincare products and equally poor advice from supposed experts. I turned to blogs, forums, and even professionals in clinical settings, only to find that no one seemed to offer safe, effective solutions. Worse, much of what I encountered was riddled with inaccuracies. No matter where I looked, I couldn’t find a single product that delivered on its promises.

I found that skin care was not created by scientists looking for the products that can make skin healthy, it was created by marketers who are exploiting skin care fads and consumer interest to generate high revenue.

As I began investigating, I uncovered some unsettling truths. For instance, I found that moisturizers often draw water out of the skin due to their formulation, which relies on humectants with a high affinity for water. I also discovered through my own experiments that hyaluronic acid does not, in fact, hold 1,000 times its weight in water—a claim parroted throughout the industry without substantiation. And perhaps most strikingly, I found that vitamin C serums do not upregulate collagen production in the skin, despite widespread claims to the contrary.

The myth surrounding vitamin C serums is a textbook example of how misinformation, repeated often enough, is accepted as truth. It highlights a glaring lack of understanding of basic biological principles among skincare bloggers, self-styled influencers, and even professionals in the field. As a biologist, I feel a sense of duty—as if I’m an officer of a kind of scientific court—to address this pervasive falsehood and prevent its continued spread.

When I first wrote about vitamin C, there was some backlash. Beauty influencers, some of whom had profited off my expertise in previous collaborations, begged me to retract my findings. One influencer in particular told me she had built her entire career and following on the claim that vitamin C serums increase collagen production. She warned me that if I didn’t remove my article, she could no longer associate with me. The irony was hard to miss—this same individual had interviewed me for her platform, earning significant income by leveraging my scientific credibility. But when I published findings that contradicted her narrative, she prioritized preserving her brand over scientific truth.

Her justification was as flimsy as it was revealing. She claimed she had “done her research” and insisted the science supported her stance. When pressed, it became clear that her “research” was based on a literature review, not primary scientific studies. As someone with a master’s degree in biology, I understood the critical difference between reviewing existing interpretations and analyzing raw data firsthand. She did not. This individual, with no scientific training, relied on a hobbyist’s understanding of skincare, bolstered by her wealthy spouse’s financial backing.

In other instances, critics avoided addressing the scientific basis of my claims altogether and instead shifted focus to the pricing of my products. This approach is inherently ad hominem, targeting me rather than the substance of my arguments. Moreover, it overlooks the significant value of what OUMERE represents: every product is crafted individually by hand, based on a decade of dedicated research and development. To dismiss the worth of products that deliver results and improve skin health is less a critique and more a deflection by those unable to engage with the science itself.

This is emblematic of a larger problem. Many bloggers and influencers rush to defend the efficacy of vitamin C serums by citing research they haven’t conducted or even read. Instead of engaging in scientific work themselves, they rely on interpretations that align with their preconceived beliefs. In most cases, they lack the resources, training, or even basic comprehension to perform meaningful experiments.

The Biological Basis of Vitamin C in Collagen Formation

Despite knowing that my findings might be dismissed or ignored, I believe in presenting them honestly and supporting them with data. Scientific truth matters, even in the face of resistance. Here is why vitamin C serums do not upregulate collagen in the skin:

Vitamin C’s role in collagen synthesis is akin to heat’s role in baking a cake—it’s necessary, but not sufficient. Heating something random, like popcorn kernels, will never produce a cake, even though heat is essential for creating a cake’s structure. Similarly, simply adding vitamin C to the skin won’t produce collagen, despite its involvement in the collagen synthesis process. This oversimplification ignores the complex interplay of factors required for collagen production, making it as absurd as expecting heat alone to bake a cake from unrelated ingredients.

While vitamin C is indeed essential to collagen synthesis, its role is supportive rather than stimulatory. Specifically, vitamin C acts as a cofactor for two enzymes—prolyl hydroxylase and lysyl hydroxylase—that are involved in the later stages of collagen production. These enzymes modify and stabilize collagen by hydroxylating proline and lysine residues in the procollagen molecule, ensuring proper folding and structural integrity. Crucially, this does not mean vitamin C initiates or increases the amount of collagen produced by cells. This enzymatic role has been well-documented in studies, including those by Peterkofsky and Diegelmann (1971), which identified the necessity of vitamin C for collagen hydroxylation but not its regulation of collagen synthesis.

Recent studies further clarify vitamin C's role in collagen-related processes. A 2017 review in Nutrients emphasized that while vitamin C is indispensable for the hydroxylation of collagen, this role is restricted to the post-translational modification stage, which supports collagen stability but does not stimulate its synthesis or gene expression. Similarly, a 2022 review in Antioxidants explored vitamin C as a cosmeceutical ingredient and concluded that while it is crucial for collagen maturation, its ability to increase collagen production is limited unless combined with other active agents. These studies confirm that vitamin C alone cannot upregulate collagen synthesis, aligning with earlier findings that collagen production depends on factors unrelated to topical vitamin C application.

Collagen production itself is governed by a complex interplay of cellular and molecular factors, including the activity of fibroblasts, growth factors such as TGF-beta, and signals from the extracellular matrix. None of these pathways are directly influenced by the topical application of vitamin C. A study by Murad et al. (1981) explored the effects of ascorbic acid on fibroblast cultures and found no significant increase in collagen synthesis, despite its necessity for proper collagen structure.

Further evidence comes from a review by Pinnell (2003), which clarified that while vitamin C improves collagen stability and reduces oxidative stress in skin, there is no direct evidence that it upregulates collagen production. Instead, collagen synthesis in skin is primarily regulated by factors like mechanical stress, hormonal changes, and cytokine signaling, none of which are mediated by vitamin C.

No evidence towards increased gene expression

The claim that topical vitamin C serums directly increase collagen gene expression lacks robust scientific support. While vitamin C is essential as a cofactor for enzymes like prolyl hydroxylase and lysyl hydroxylase, which are involved in collagen maturation, it does not initiate or upregulate collagen production at the genetic level. Research indicates that vitamin C stabilizes collagen molecules post-synthesis but does not directly stimulate the transcription of collagen genes. (Schagen, 2017; Packer et al., 2002).

Skin Barrier and Absorption Limitations

The skin's outermost layer, the stratum corneum, serves as a primary barrier to external substances, including topical agents. Vitamin C, particularly in its active form as L-ascorbic acid, is hydrophilic and has difficulty penetrating this lipid-rich barrier. Studies indicate that for vitamin C to be absorbed through the skin, it must be formulated at a pH below 4.0, which most vitamin C serums are not, and vitamin C if it is formulated at an acidic pH and applied to skin will cause irritation. 

Additionally, the concentration of vitamin C that reaches the dermal fibroblasts—the cells responsible for collagen production—is often insufficient to have a meaningful impact. Oral supplementation of vitamin C ensures systemic distribution and cellular uptake, facilitating its role in collagen synthesis more effectively than topical application.

Metabolic Requirements

Once absorbed, vitamin C must reach the dermal layer, where collagen synthesis occurs. However, the concentration of vitamin C that penetrates the skin is  insufficient. Oral ingestion of vitamin C allows for systemic distribution and cellular uptake, facilitating its role as a cofactor in collagen synthesis. In contrast, topical application does not guarantee adequate delivery to the dermal fibroblasts responsible for collagen production.

Concentration Challenges

To achieve a meaningful effect on collagen synthesis, topical formulations would need to deliver higher concentrations of vitamin C to the dermis than formulations would allow. Maintaining such concentrations is not realistic due to the vitamin's instability and the skin's absorption limitations. The vast majority of the vitamin destabilizes before first use by a user because vitamin C serums are mass manufactured and stored for months or years in hot warehouses before reaching the consumer. Moreover, high concentrations can lead to skin irritation and oxidative degradation, rendering the vitamin ineffective.

Scientific Perspective

The notion that simply applying vitamin C topically can upregulate collagen synthesis overlooks the complex physiological processes involved. Effective collagen production requires not only the presence of vitamin C but also its proper delivery to target cells in sufficient quantities, a feat not easily accomplished through topical application. This oversimplification is akin to expecting heat alone to bake a cake without the necessary ingredients and preparation.

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The idea that vitamin C can single-handedly stimulate collagen production oversimplifies the biology of skin and promotes a misconception widely propagated by the skincare industry. This misunderstanding highlights the need for more clarity in skincare science and better consumer education. While vitamin C does play a valuable role in maintaining collagen quality, it is biologically implausible for it to increase collagen production on its own. Studies like those mentioned above could further debunk this pervasive myth, enabling consumers to make more informed decisions about their skincare routines.

How Vitamin C Serums Decrease Collagen in the Skin

While vitamin C is essential for collagen synthesis, its oxidized form may have detrimental effects. Oxidative stress can impair cellular functions and create an aberrant extracellular matrix environment, which negatively affects the skin's structure and function. Elevated reactive oxygen species (ROS) levels can lead to collagen degradation, compromising skin integrity. 

Furthermore, the most common complaint among those who use vitamin C serums are an outbreak of acne, increased skin redness, increased skin sensitivity and rosacea flareups. 

Current Outlook

In my laboratory right now I have been working on a study using human participants and studying the dermal changes over time when a vitamin C serum is topically applied compared to a control. I have actually been working on various versions of this experiment for a couple of years now and have a lot of raw data. I have not been able to find any significant results to show that vitamin C serums increase collagen or improve dermal thickness in healthy individuals. I look to individuals not deficient in vitamin C as to not create false findings, and then look at the changes over time and I have yet to find conclusive results. The best results I have seen are from a skin care routine that avoids vitamin C serums, skin care containing fragrance, creams and hyaluronic acids.

Team Skin Health

If there are sides in skin care, I am on the side for team health and anti-aging. If vitamin C serums actually increased collagen, I would absolutely be on that team because I would want it for myself because I, like everyone else, want to keep my skin young. So any product or ingredient that can conclusively do that is one that I want. And one I would want to add to the OUMERE line.

If OUMERE had a vitamin C serum, I could probably add multiple millions to my yearly sales, but I just cannot make a product that I know does not help skin and one that seems to have a false-scientific backing. But I like to keep an open mind in the name of scientific progress and welcome any individuals research from their own lab that shows human studies on non-vitamin C deficient individuals of mature adult age who shown an increase in collagen from the topical application of vitamin C. I just have not seen it done yet.

 

References

Peterkofsky, B., & Diegelmann, R. (1971). The role of ascorbic acid in the biosynthesis of collagen. Archives of Biochemistry and Biophysics, 143(2), 228–238.

Murad, S., et al. (1981). Regulation of collagen synthesis by ascorbic acid. Proceedings of the National Academy of Sciences USA, 78(5), 2879–2882.

Pinnell, S. R. (2003). Regulation of collagen biosynthesis by ascorbic acid: A review. Journal of the American Academy of Dermatology, 48(5), 87–90.

Pullar, J. M., Carr, A. C., & Vissers, M. C. M. (2017). The roles of vitamin C in skin health. Nutrients, 9(8), 866.

Khan, F. A., et al. (2022). Vitamin C as a cosmeceutical: Antioxidant properties and collagen support. Antioxidants, 11(9), 1663.

Kammeyer, A., & Luiten, R. M. (2015). Oxidation events and skin aging. Current Problems in Dermatology, 44, 146–154.

Schagen, S. K. (2017). Topical vitamin C and the skin: Mechanisms of action and clinical applications. In Skin Aging Handbook: An Integrated Approach to Biochemistry and Product Development (pp. 125-139). Springer.