Table 2.

Effects of green tea supplementation on photoaging, stress resistance, neuroprotection, and associated health complications: outcomes of clinical trials.

No.	Compound(s)/Extract(s) Used	Subjects Used	Duration	Treatment Method	Results	Ref.
1	Green tea polyphenols	12 human volunteers between 18–65 years	3 months	Consume capsules of green tea polyphenols	Conjugate metabolites in plasma, blister fluid, and skin biopsy samples	[89]
2	Green tea extract	18 human volunteers between 21 and 71	34 days	Topical application	Reduction in the level of cells with sunburn	[90]
3	Green tea extract	Human volunteers aged between 18 and 50	-	Topical application ranging from 0.25 to 10% Topical applicationof 5% EGCG, EC, and EGC	Decreased sunburn cells by 66% 0.5 to 2.5% concentration showed optimum activity Lesser activity when compared to the crude extracts	[91]
4	Green tea extract	10 human volunteers	15 min prior to UV irradiation and immediately after exposure	Topical application	Lesser DNA damage when compared to vehicle control	[92]
5	Green tea extract	20 Chinese women	30 min prior to UV irradiation and 6, 24, and 48 h after exposure	Topical application (2–5%)	3% of topical application showed less erythema, mild pigmentation, controlled level of thickening of stratum corneum and epidermis, and reduction of matrix metalloproteases	[93]
6	Green tea extract	42 Korean females	8 weeks	Topical application at crow’s feet	Free radical scavenging and antiwrinkle effects	[94,95]
7	Green tea polyphenols	56 women aged 25 to 75	2 years	Oral supplements of 250 mg green tea polyphenols	Improvement in facial skin and in controlling erythema	[96]
8	Green tea extract	2015 subjects aged over 65 years	6 months	Oral consumption	Reduced the prevalence of Alzheimer’s disease and cognitive impairment	[171]

epicatechin (EC); epigallocatechin (EGC).