From the Guidelines

Tea has a positive effect on dermatological (skin) health.

Tea, particularly green tea, contains flavonoids such as catechins, which have anti-inflammatory and anti-glycative properties 1.
Catechins, especially epigallocatechin gallate (EGCG), have been shown to reduce the advanced glycation process, accumulation of AGE, and cross-linking of collagen in diabetes 1.
Tea consumption may contribute to the reduction of endogenous AGE/ALE accumulation, which can modulate the glycaemic response and have a positive effect on skin health 1.
Some studies suggest that green tea or Polypodium leucotomos extract may decrease long-term carcinogenesis and protect against photochemical damage, which can be beneficial for skin health 1.
The anti-glycative activity of tea is associated with its ability to inhibit the formation of AGE and trap reactive dicarbonyl species, such as methylglyoxal (MGO) and glyoxal (GO) 1.

The anti-glycative properties of tea are thought to be due to the presence of polyphenols, which can inhibit the biosynthesis of AGE through their antioxidant properties, metal-chelating ability, protein interaction, and MGO trapping 1.
The flavonoids present in tea, such as quercetin and kaempferol, have been shown to have anti-inflammatory and anti-glycative activities, which can contribute to the positive effect of tea on skin health 1.

The evidence suggests that tea, particularly green tea, has a positive effect on dermatological (skin) health due to its anti-inflammatory and anti-glycative properties, and its ability to inhibit the formation of AGE and trap reactive dicarbonyl species.

From the Research

The consumption of green tea has been shown to have antioxidant, anti-inflammatory, and anti-carcinogenic properties, which can be beneficial for skin health 2, 3, 4.
Green tea polyphenols, particularly (-)-epigallocatechin-3-gallate (EGCG), have been found to inhibit chemical carcinogen- or ultraviolet radiation-induced skin carcinogenesis in laboratory animal models 2, 3.
Topical treatment or oral consumption of green tea polyphenols has been shown to prevent UVB-induced inflammatory responses, immunosuppression, and oxidative stress in skin 2, 3.
Green tea has been found to have photoprotective effects, which can help prevent solar UVB light-induced skin disorders, including photoaging, melanoma, and nonmelanoma skin cancers 2, 3, 5.
Clinical evidence supports the use of oral green tea preparations to protect skin from damage induced by ultraviolet radiation, but more studies are needed to confirm its efficacy in other skin disorders 5.
Topical application of green tea extract may be effective for various dermatologic conditions, including atopic dermatitis, acne vulgaris, rosacea, androgenetic alopecia, and others 6.

Protection against UV-induced skin damage and skin cancer 2, 3, 5
Anti-inflammatory and antioxidant effects 2, 3, 4
Potential treatment for various dermatologic conditions, such as atopic dermatitis, acne, and rosacea 6
May help prevent photoaging and improve skin health 2, 3, 5

More clinical studies are needed to confirm the efficacy of green tea in various skin disorders 5, 4, 6
Further research is required to understand the molecular mechanisms of green tea's effects on skin health 3
Safety risks and potential interactions with other medications need to be considered when using green tea preparations for skin health 5