T Nation

How Quickly Does an AI Take to Work?

Evening all

Currently running my first cycle 300mg test E a week. 5 weeks in of an 8 week cycle. Pretty tame eh.

My prebloods showed I have had fairly high E but in ranage and low shgb 14.

Anyway first few weeks have been fine but last few days my heart feels like it is pounding hard but not not particularly faster, I suspected high E2 given I’m naturally high in it so took about 0,6mg of letrozole and within half an hour things resolved themselves.

My question can it happen that quick or maybe the symtoms are in my head (anxiety) and the Letro acted as a placebo?


The half life of E2 in the blood is around 2 hours (the studies don’t look that solid though) so it should work very fast. If you block the aromatase completely, in 10 hours you should be at 0 E2. I would say the data is a bit overstated but it emphasizes that it works fast and you should be careful not using too much.

1 Like

The times I felt better in a couple hours (or in the same day) were the times I took too much, and felt low e2 2-4 days later. I use that as a metric when I take AI now


Thanks for this. So I guess it could have been that then, i feel much better today no pounding heart. Probs needs keep a better watch on E2 sides which I dismissed initially as doing a mild cycle but i must be sensitive to it.

I don’t think the pounding heart thing is in your head. I’ve had that before, usually at night. Not sure if it’s e2 related or not but on low test and anavar I don’t get it. High test, high NPP and anavar I do get it. High being 400mg plus. Low being 200mg or less.