Background: Ultraviolet radiation in the skin causes photodamage, immunosuppression and oxidative stress, which can lead to more serious skin disorders. As a result, there is a growing trend of using cosmetic products that are intended to protect against the sun and treat the consequences that the sun leaves on our skin (wrinkles, hyperpigmentation, skin cancer...). There is an increasing interest in cosmetic products that contain active ingredients of natural origin, such as green tea polyphenols, instead of synthetic active ingredients. Green tea polyphenols are naturally occurring substances that have photoprotective effects on the skin through antioxidant, chemoprotective, repairing and many other mechanisms.
Methods: For a more comprehensive review of the literature that answers the research question, we conducted a systematic review of the literature published between 2000 and 2024 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. For the search of relevant literature, we compiled search strings that were used in the PubMed and Web of Science databases. With the help of the Guidelines designed to assist with choosing population, intervention, comparison and outcome approach published by the Critical Appraisal Skills Programme, we then eliminated inappropriate literature. Selected articles were reviewed and analysed.
Results: By taking into account all limiting criteria and guidelines, we selected 16 scientific articles. Our selection included 7 review articles and 9 clinical studies. We reviewed all articles, analysed them according to the year of publication, country of origin, and collected them in a spreadsheet, where we recorded renewals of review articles and key features of clinical trials. Review articles include a general presentation of green tea polyphenols and a description of their photoprotective mechanisms, while clinical studies mainly describe the results of photoprotective effects of dermal application of green tea polyphenols on the skin.
Conclusion: Dermal application of green tea polyphenols protects the skin from photodamage caused by excessive exposure to ultraviolet radiation. Green tea polyphenols have been proven to provide anti-inflammatory, immunomodulatory and antioxidant effects on the skin, protecting it from UV-induced damage, as well as having the ability to repair damage that has already occurred. Green tea polyphenols are suitable for inclusion in anti-aging cosmetics, sunscreen products and products for after sun care.
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