RESEARCH: Green Tea Extracts
The skin has three layers, and the tea plant's compounds affect each layer differently. In the outer layer (stratum corneum), tea extracts act as strong antioxidants, protecting the skin from damage. In deeper layers, they protect against ultraviolet radiation, delay signs of aging, and improve blood vessel health.
Tea catechins, found in extracts from the tea plant, have various positive effects on the skin, particularly in protecting against damage caused by free radicals and UV radiation.
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Effects on Free Radicals:
- Directly neutralizing reactive oxygen and nitrogen species.
- Chelating trace elements (e.g., copper, iron) involved in free radical generation.
- Boosting the production of endogenous antioxidant enzymes (e.g., superoxide dismutase, glutathione).
- Inhibiting enzymes that generate reactive oxygen species.
- Protecting and regenerating other antioxidants like vitamin C and E.
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Antioxidant Properties in Cosmetics:
- Tea extracts are widely used in cosmetics for their antioxidant properties.
- Free radicals, responsible for skin aging, are counteracted by tea polyphenols.
- Polyphenols protect and replenish vitamin C, crucial for collagen production, vital for skin elasticity.
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Photoprotective Activity (Protection against UV Radiation):
- UV radiation can harm the skin, leading to skin cancers and aging.
- Tea leaf extracts, especially green tea, absorb UV radiation.
- Tea extracts, when applied topically or consumed orally, protect against UV-induced damage and inhibit skin aging.
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Enhancement of Skin Microcirculation:
- Tea polyphenols improve blood flow and oxygen delivery to the skin.
- Significant improvements in skin parameters like elasticity, roughness, and water balance have been observed.
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Anti-Inflammatory and Anti-Cancer Effects:
- Green tea extract has anti-inflammatory and anti-cancer properties, inhibiting collagenases and protecting skin cells.
- Effective in preventing epithelial deterioration caused by UVB radiation.
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Other Skin Benefits:
- Reduction of cellulite and slimming effects observed in clinical trials.
- Improvement in skin and hair condition, including increased hair growth.
- Significant reduction in sebum production, contributing to improved skin health.
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Combination with Other Extracts:
- Combining tea extracts with other botanical extracts, such as Ginkgo biloba, enhances their photoprotective activity.
Clinical Studies
The concentration of green tea extract is considered effective at around 5% in cosmetic formulations. Yet, na
Despite the popularity of green tea in cosmetics, there is limited scientific data, especially from clinical experiments.
Some clinical studies suggest positive outcomes:
- One study found that a gel with green tea extract compound EGCG improved skin texture and appearance in 45% of participants after four weeks.
- Another study using formulations with 6% green tea leaf extracts showed increased skin moisture, improved microrelief, and enhanced skin smoothness after topical application.
- Green tea-based cosmetics are also marketed for reducing excess sebum production, particularly beneficial for oily skin. Clinical studies have demonstrated the efficacy of green tea extract in decreasing sebum production, with formulations containing higher concentrations showing better results.
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Double-blinded, placebo-controlled trial of green tea extracts
This study looked at the effects of using a combination of green tea cream and green tea supplements on the skin of women with moderate signs of aging due to sun exposure. The participants applied the green tea cream and took green tea supplements for 8 weeks. While there were no noticeable changes in the overall appearance of the skin, microscopic examination of skin samples showed improvement in the elastic tissue. This suggests that green tea might have positive effects on the skin at a deeper level, but longer use may be needed to see visible improvements in the skin's appearance. (source: https://pubmed.ncbi.nlm.nih.gov/16029678/ )
In conclusion, while some studies suggest the positive effects of green tea in cosmetic formulations, it's essential to approach these claims with a critical mindset. More rigorous scientific research, especially clinical trials, is needed to better understand the full benefits of green tea in skincare. (source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6930595/ )
