The effects of green tea on acne vulgaris: A systematic review and meta-analysis of randomized clinical trials

Green tea extract (GTE) has been studied for the treatment of acne based on its anti-inflammatory/antioxidant properties. This systematic review and meta-analysis aimed to examine the effects of GTE on acne. Electronic databases, including PubMed, Embase, and the Cochrane Library were systematically searched up to August 2019. The effect size of acne lesion counts is presented as mean differences and 95% confidence intervals (CIs). Five randomized-controlled studies were included in the meta-analysis (N; experimental = 125, control = 122). GTE significantly reduced the number of inflammatory lesions (-9.38; 95% CI: -14.13 to -4.63). In subgroup analysis, topical GTE application significantly reduced the inflammatory lesion counts (-11.39; 95% CI: -15.91 to -6.86) whereas oral GTE intake showed minimal effect (-1.40; 95% CI: -2.50 to -0.30). Although GTE did not significantly reduce the number of non-inflammatory lesions (-21.65; 95% CI: -47.52 to 4.22), when stratified by the route of admission, non-inflammatory acne lesions were significantly reduced by topical GTE application (-32.44; 95% CI: -39.27 to -25.62) but not with oral GTE administration (0.20; 95% CI: 0.00 to 0.40). This systematic review and meta-analysis suggest that topical GTE application is beneficial for the treatment of acne without causing significant adverse events while oral GTE intake has limited effects. Further high-quality clinical trials are warranted.