Updated and contextualized version of an article originally published on July 28, 2021
The article retains its original focus by presenting it through a scholarly and accessible perspective, supported by verifiable references.
Authors
- Dr. A. Conte – Biologist
- Roberto Panzironi –Independent researcher
Note editoriali
- First publication: July 28, 2021
- Last update: April 18, 2026
- Version: 2026 narrative revision
IN BRIEF
- Vitamins such as C, A, and E, and certain minerals support biological functions of the skin and ocular surface, with plausible biological mechanisms (enzymatic cofactors, antioxidant action, membrane stability).
- Vitamin C is essential for collagen synthesis and has antioxidant roles whether taken systemically or applied topically; clinical evidence for cosmetic effects is encouraging but variable.
- Other micronutrients (vitamin D, vitamin A, vitamin E, omega-3) show associations with skin and ocular health; evidence differs in quality and clinical context.
- For many indications, the evidence is observational or based on small studies; targeted interventions require individual clinical evaluation and prudence.
Abstract: what does science say?
The body of evidence suggests that certain micronutrients contribute to the structure and function of the skin and ocular surface through known biological mechanisms: vitamin C is a cofactor for collagen chain hydroxylation and has antioxidant action; vitamin A is central to the visual cycle and epithelial homeostasis; vitamin E protects lipid membranes from oxidation; vitamin D is associated with cutaneous inflammatory outcomes; omega-3 can modulate inflammatory processes of the lacrimal glands. However, the strength of the evidence varies: some derived from preclinical studies and small trials, others from reviews and meta-analyses that document associations rather than causal proof. Concrete effects depend on dose, chemical form (e.g., L-ascorbic versus stabilized derivatives), route of administration (oral vs. topical), duration, and population studied. In the absence of strong and uniform evidence, a prudent approach favors a diet rich in fruits, vegetables, and food sources of nutrients, targeted supplementation only when indicated, and the use of topical formulations evaluated in clinical studies. Methodological limitations and individual variability require cautious interpretation of recommendations.
MAIN SECTION
Vitamin C: biological role and evidence for skin and connective tissue
Vitamin C (ascorbic acid) is an indispensable cofactor for enzymes that hydroxylate proline and lysine during collagen formation; this role is the biological basis for the importance of vitamin C in skin and capillary integrity. Recent studies and reviews consider systemic and topical use: reviews on cosmetic formulations show that well-formulated products can increase collagen production and improve skin parameters in short-to-medium term clinical studies [1]. Clinical trials on oral supplementation or nutritional combinations show effects on collagen synthesis and tissue healing in surgical and repair contexts, but the practical effect depends on the dose, combination with other nutrients (e.g., zinc, amino acids), and treatment period [2]. Systematic reviews highlight the presence of evidence but also the need for larger and more standardized studies to define expected doses and results [3].
Topical vitamin C and derivatives: efficacy and limitations
Topical application of ascorbic acid or its derivatives (e.g., magnesium ascorbyl phosphate, MAP) is studied for photo-aging, dyschromia, and improvement of skin texture. Recent reviews of controlled clinical trials show favorable effects on skin radiance and spot reduction, albeit with heterogeneous results related to concentration, formulation stability, and delivery system [4]. In vitro and clinical studies indicate that MAP and other pro-drugs provide ascorbate more stably and modulate inflammatory biomarkers in sebaceous cells, suggesting plausibility for anti-inflammatory and brightening effects [5]. However, the duration required for visible results and interindividual variability remain factors to be evaluated when advising on use.
Vitamins A, D, E and micronutrients for skin and vision
Vitamin A is fundamental in the visual cycle: its derivatives (retinal/retinol) reconstitute the chromophore necessary for rhodopsin formation and vision in low light conditions; prolonged deficiencies cause night vision deficits and retinal alterations. In the cutaneous field, retinoids modulate cell turnover and epidermal differentiation, with documented efficacy on photo-aging and hyperkeratosis [6]. Vitamin E, a fat-soluble vitamin, protects cell membranes from oxidation and can promote the repair of the membranes themselves; experiments and clinical studies show protection from oxidative damage and a synergistic role with other antioxidants in skin photoprotection [7]. Studies on combined supplements (carotenoids plus vitamin E) have shown a reduction in UV radiation-induced erythema, demonstrating a partial dietary photoprotective effect [8]. Vitamin D is involved in cutaneous immune regulation; low levels have been associated with inflammatory conditions such as eczema and psoriasis, but the causal relationship and indications for therapeutic supplementation remain to be rigorously defined.
Omega-3, magnesium, zinc, and other nutrients: what supports vision and the ocular surface
Omega-3 fatty acids (EPA/DHA) have been proposed for their potential anti-inflammatory effect on the lacrimal glands and ocular surface. A large multicenter randomized trial (DREAM) showed no significant clinical benefits compared to placebo for the management of dry eye disease, indicating that the role of omega-3 remains uncertain and is likely conditioned by the context and population studied [9]. Minerals such as zinc participate in enzymatic repair processes; magnesium, and derivatives such as magnesium ascorbyl phosphate in cutaneous formulations, show anti-inflammatory effects in cellular models and preliminary results in clinical studies [5]. Overall, biological plausibility exists, but clinical efficacy varies according to the condition and study design.
What it means in practice
From a practical standpoint, evidence indicates that: promoting a diet rich in fruits and vegetables ensures the natural intake of antioxidant vitamins and minerals; for collagen function, vitamin C is essential as a cofactor, so an adequate diet and, if indicated, supplementation evaluated by a doctor are rational [1][2][3]. The topical use of vitamin C can help improve radiance and dyschromia if a stable formulation with a clinically tested concentration is chosen [4][5]. For specific problems (eczema, psoriasis, dry eye), the literature supports associations but does not prescribe standard solutions: for example, the evidence on the usefulness of omega-3 in forms of dry eye is conflicting, and a large trial did not show clear benefits [9]. For this reason, decisions on integrations or treatments must be based on individual clinical evaluation, measurement of any deficiencies (e.g., 25-OH-D for vitamin D), and attention to forms, doses, and possible drug interactions. In the cosmetic field, it is advisable to prefer products with published clinical data rather than relying on unsupported claims.
KEY POINTS TO REMEMBER
- Vitamin C is biologically necessary for collagen synthesis; topical applications and supplementation have plausibility and some supporting clinical data.
- Vitamin A is central for vision and epidermal differentiation; its intake must respect safety limits.
- Vitamin E protects lipid membranes and can be integrated into antioxidant strategies; nutritional combinations can offer photoprotective benefits.
- Omega-3 show anti-inflammatory mechanisms but clinical evidence on dry eye is conflicting; large RCTs have not confirmed clear benefits.
- A varied diet based on whole foods is the first recommended measure; supplementation and topical treatments should be evaluated on a case-by-case basis.
Limitations of Evidence
It is important to distinguish between association, biological plausibility, and causal proof. Many observations come from in vitro studies, animal models, or small clinical trials; this reduces the strength of conclusions applicable to the general population. Observational studies can document correlations between serum micronutrient levels and skin or eye conditions, but do not necessarily establish causality. Even in RCTs, heterogeneity in dose, formulation, duration, outcome criteria, and participant characteristics makes it difficult to generalize results. An example is research on omega-3 for dry eye: smaller studies had shown positive signals, but a large multicenter trial did not confirm a significant benefit [9]. Furthermore, the effect of topical formulations depends on chemical stability and skin penetration; not all forms of vitamin C are clinically equivalent [4][5]. Finally, individual variability (age, nutritional status, sun exposure, comorbidities, medications) strongly influences results and requires cautious interpretation of recommendations.
Editorial Conclusion
Scientific literature supports the idea that certain vitamins and minerals are beneficial for skin and vision function due to well-characterized biological mechanisms. However, practical application requires balance: a diet rich in plant-based foods remains the most solid starting point. For targeted supplementation or topical therapies, preferring interventions evaluated in published clinical studies and agreeing on choices with healthcare professionals is the most prudent approach. Research continues to evolve: larger and more standardized trials are needed to define doses, formulations, and populations that can benefit. Until then, public communication must remain sober, transparent, and based on verifiable data.
Editorial note
This article was originally published in the past and has been updated following criteria of scientific accuracy and clarity for public dissemination. The text is for informational purposes only and does not replace medical advice. For diagnostic or therapeutic evaluations, consult a healthcare professional.
SCIENTIFIC RESEARCH
- Boo YC. Ascorbic Acid (Vitamin C) as a Cosmeceutical to Increase Dermal Collagen for Skin Antiaging Purposes: Emerging Combination Therapies. Antioxidants. 2022. [https://doi.org/10.3390/antiox11091663]
- Kjaer M et al. Multinutrient Supplementation Increases Collagen Synthesis during Early Wound Repair in a Randomized Controlled Trial. J Nutr. 2020. [https://doi.org/10.1093/jn/nxz324]
- Efficacy of Vitamin C Supplementation on Collagen Synthesis and Oxidative Stress After Musculoskeletal Injuries: A Systematic Review. Orthop J Sports Med. 2018. [https://doi.org/10.1177/2325967118804544]
- Efficacy of topical vitamin C in melasma and photoaging: A systematic review. J Cosmet Dermatol. 2023. [https://doi.org/10.1111/jocd.15748]
- Lee WJ et al. Magnesium Ascorbyl Phosphate Regulates the Expression of Inflammatory Biomarkers in Cultured Sebocytes. Ann Dermatol. 2015. [https://doi.org/10.5021/ad.2015.27.4.376]
- Review: The Role of Vitamin A in Retinal Diseases. Nutrients. 2016. [https://doi.org/10.3390/nu8110746]
- Gibbs et al. Promotion of plasma membrane repair by vitamin E. Nat Commun. (Article: ncomms1594). [https://doi.org/10.1038/ncomms1594]
- Stahl W, Sies H, Tronnier H, Heinrich U. Carotenoids and carotenoids plus vitamin E protect against ultraviolet light‑induced erythema in humans. Am J Clin Nutr. 2000. [https://doi.org/10.1093/ajcn/71.3.795]
- The Dry Eye Assessment and Management (DREAM) Study Research Group. n‑3 Fatty Acid Supplementation for the Treatment of Dry Eye Disease. N Engl J Med. 2018. [https://doi.org/10.1056/NEJMoa1709691]
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