Polyphenon E is a preparation that is decaffeinated and contains defined green tea catechins. Catechins are known to be powerful antioxidants, antimicrobial agents, anticancerous agents and have anti-inflammatory properties. The predominant catechin in green tea is epigallocatechin gallate (EGCG) and it is reported to be the most beneficial catechin in green tea.
Researchers conducted a trial focused on the effects of dosages of Polyphenon E on human subjects and its effect on UV-induced skin redness.1 The dosages, administered randomly were 800 mg EGCG once a day, 400 mg EGCG twice a day, 800 mg EGCG as Polyphenon E once a day, 400 mg EGCG twice a day as Polyphenon E or placebo once a day. The 800 mg EGCG per day dosage is equivalent to the amount of EGCG in 8-16 cups of green tea per day. There were 8 subjects assigned to each dosage and the treatment period was 4 weeks.
Results included more than 60% increase in EGCG in the blood at the highest dosage of EGCG or Polyphenon E. There were no significant changes in blood chemistry after 4 weeks and none of the treatments protected skin from UV light damage, as indicated by skin redness.
A study was conducted by Chow and others to assess catechin availability in human test subjects following single doses of EGCG or Polyphenon E at 4 dosage levels.2 There were 5 subjects assigned to each of four dose levels, 200, 400, 600 and 800 mg EGCG. Blood and urine samples were collected until 24 hours following ingestion of the EGCG product. Concentration of EGCG in blood was significantly higher with the 800 mg dosage than with the other 3 dosages. No differences were observed based on the source of EGCG (pure EGCG or Polyphenon E).
Scientists have found that bioavailability of catechins is low when they are taken orally. A 2005 study was conducted to test the hypothesis that catechin levels in humans are higher when the catechins are ingested after fasting. The treatments were 400, 800 or 1200 mg Polyphenon E, based on EGCG content. There were 10 subjects for each treatment and they participated in an overnight fast before receiving the supplement. One half of the subjects were given one or two muffins and water before treatment and the other half did not. After one week the subjects were crossed over and received the same Polyphenon E dosage with the opposite fast/fed condition.
EGCG in the blood was present as metabolites, meaning the compound had been broken down in the subject’s body. Other catechins were present in the blood in their original form (epicatechin and epigallocatechin). The catechins in their original form in the blood were more than 3.5 times higher when Polyphenon E was taken in the fasting condition as compared to taken with food. The researchers concluded that better bioavailability of catechins in the blood are achieved when Polyphenon E is given orally under fasting conditions. They also concluded that the optimum dosage to realize the best health benefits from catechins was 800 mg EGCG and that this dosage is tolerated well by subjects undergoing an overnight fast.
1Pharmacokinetics and safety of green tea polyphenols after multiple-dose administration of epigallocatechin gallate and polyphenon E in healthy individuals. Chow HH, Cai Y, Hakim IA, Crowell JA, Shahi F, Brooks CA, Dorr RT, Hara Y, Alberts DS. Clin Cancer Res. 2003 Aug 15;9(9):3312-9.
2Phase I pharmacokinetic study of tea polyphenols following single-dose administration of epigallocatechin gallate and polyphenon E. Chow HH, Cai Y, Alberts DS, Hakim I, Dorr R, Shahi F, Crowell JA, Yang CS, Hara Y. Cancer Epidemiol Biomarkers Prev. 2001 Jan;10(1):53-8.
3Effects of dosing condition on the oral bioavailability of green tea catechins after single-dose administration of Polyphenon E in healthy individuals. Chow, HH; Hakim, IA; Vining, DR; Crowell, JA; Ranger-Moore, J; Chew, WM; Celaya, CA; Rodney, SR; Hara, Y and Alberts, DS. Clin Cancer Res. 2005. 11(12):4627-33.
