Finally, drinking green tea can generally result in healthy skin. In a study conducted by Wilhelm STAHL, the aim was to observe the effects of green tea polyphenols on the skin properties of 60 women. Over a period of 12 weeks, the participants consumed either a beverage containing green tea polyphenols providing 1402 mg of total catechins (green tea flavonoid) per day, or a control beverage. Photoprotection, skin structure and function were measured at the start (week 0), week 6 and week 12.
Following exposure of skin areas to UV rays, the UV-induced erythema significantly decreased in the intervention group, by 16 and 25% after 6 and 12 weeks, respectively. The structural characteristics of the skin that were positively affected include elasticity, roughness, scaling, density, and water homeostasis. Consumption of the green tea polyphenol-based drink for 12 weeks increased blood flow by 29% and oxygen supply to the skin. Similarly, in a separate single-dose study (0.5, 1, and 2 g) of green tea polyphenols, blood flow was maximised 30 minutes after ingestion. In summary, it has been demonstrated that the green tea polyphenols contained in a drink contribute to improving skin quality in women.
Maintaining the integrity of the skin is vital for its function and appearance, and requires an optimal intake of nutrients. It has been observed that the ingestion of green tea catechins improves skin hydration, transepidermal water loss (TEWL), density, and elasticity. The improvement in skin structure may also be linked to the increase in skin blood flow due to flavonoids. Microcirculation is important for the supply of nutrients and oxygen to the skin. In the previous study, skin blood flow increased in volunteers who consumed a green tea flavonoid-enriched drink for 12 weeks. This finding could be one of the mechanisms involved in the improvement of skin condition.