Across 635 first-hand reports, people mentioned a side effect 25 times (about 4 per 100 reports). The most common: insomnia, liver damage, liver failure. User reports show what people notice — they can't tell you whether Green Tea Extract is safe for you.
“It definitely increases fat burning. I have noticed that, as have multiple people in our office. However, it's not going to feel like caffeine.”
“When I drink a good quality green tea, I'm in a better mood, relaxed, feel more creative and it becomes easier to concentrate.”
“I was taking green tea extract for a couple of months, it gave me great energy but apparently it can be bad for your liver.”
Conclusion: 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.
Conclusion: A safe intake level of 338 mg EGCG/day for adults was derived from toxicological and human safety data for tea preparations ingested as a solid bolus dose. An Observed Safe Level (OSL) of 704 mg EGCG/day might be considered for tea preparations in beverage form based on human AE data.