Comment · Fri, October 9, 2020 · ND Owner
How long does EGCG's inhibition of emzymes last?
Original post in this thread
3ric843 · 4 points
Hello everyone,
I always felt like when I took green tea catechins along with my caffeine, that the caffeine lasted longer. I decided to research this, and I found this study:
https://pubmed.ncbi.nlm.nih.gov/27518169/
It states that EGCG inhibits CYP1A2, which is the enzyme that metabolises caffeine. So now I know to use less caffeine and stop drinking it earlier in the day when I take EGCG. What I'm worried about is that on work days, I workout after work, at 16:00. I usually drink some yerba mate between 14:00-14:30, which usually is the latest I can drink caffeine without it affecting my sleep. So if I took a green tea extract tablet at 6:30, would the enzymes be still inhibited 8 hours later, extending the caffeine's effect to the point of affecting my sleep?
I know that the best way to know is to try it, but I have a workout after work, and really want to sleep well tonight, so...
What they were answering
Direct reply to the original post — see the thread post above.
u/MisterYouAreSoDumb · ND Owner
That is an in-vitro study. The in-vivo human study I found shows that tea catechins' effects on human CYP metabolism is negligible.
Effects of Repeated Green Tea Catechin Administration on Human Cytochrome P450 Activity
Results: There are large between-subject variations in CYP enzyme activities in healthy individuals. Four weeks of green tea catechin intervention did not alter the phenotypic indices of CYP1A2, CYP12D6, and CYP12C9, but resulted in a 20% increase (P = 0.01) in the area under the plasma buspirone concentration-time profile, suggesting a small reduction in CYP3A4 activity.
Conclusions: We conclude that repeated green tea catechin administration is not likely to result in clinically significant effects on the disposition of drugs metabolized by CYP enzymes.
For CYP2C9 specifically, they say this:
For CYP2C9 phenotypic assessment, the mean baseline losartan to E3174 ratio was 1.53 with values ranging from 0.38 to 4.78. Four weeks of green tea catechin intervention did not result in significant changes in CYP2C9 phenotypic index. The geometric mean ratio of posttreatment over baseline CYP2C9 index was 1.07 (90% CI, 0.91-1.08).
So I wouldn't be too worried. There is only one way to know how you will personally respond, though.