][3] Trace amounts are found in apple skin, plums, onions, hazelnuts, pecans, and carob powder (at 109 mg per 100 g).

[2] When taken orally, EGCG has poor absorption even at daily intake equivalent to 8–16 cups of green tea, an amount causing adverse effects such as nausea or heartburn.

[7][8][9][10] A 2011 analysis by the European Food Safety Authority found that a cause and effect relationship could not be shown for a link between tea catechins and the maintenance of normal blood LDL-cholesterol concentration.

[11] A 2016 review found that high daily doses (107 to 856 mg/day) taken by human subjects over four to 14 weeks produced a small reduction of LDL cholesterol.

[18] The warnings were issued because the products had not been established as safe and effective for their marketed uses and were promoted as "new drugs", without approval as required under the Act.