Is it okay to drink 6 to 8 cups of green tea a day (sugarless). does it have any adverse effects on my body?

Most recommend: limiting to 5 cups of green tea per day. Overdose of Green Tea (usually extract) may lead to irritability, insomnia, irregular or rapid heart rate, muscle twitching, nausea, vomiting, diarrhea, abdominal cramps, liver damage, trouble breathing, dizziness, fever, confusion, hallucinations, diuresis, seizures, loss of consciousness & even death.