Peter Attia, M.D.

This was a wake-up call because I think there were a lot of doctors out there who were prescribing aromatase inhibitors to keep estrogen as low as possible in men.

Who were taking testosterone.

Yeah.

Within physiologic norms.

Yeah.

Okay.

So again, yeah.

Putting aside bodybuilders who are taking a thousand milligrams of testosterone where you do have to block some of the aromatization.

But if you have a guy who's taking 100 or 150 milligrams of testosterone a week, which would put him to a physiologic upper limit of normal, really, it seems to me you ought to let estrogen go as high as necessary or as high as it goes naturally shy of producing a symptom.

And so let's just spend a minute now talking about the role of estrogen and its role in the brain.

What do we know about this?

And do we know about, for example, why at a minimum in some of these studies and even anecdotally, if a male's estrogen level is too low, it has a negative impact on his mood?

Libido was definitely one.

I don't recall.

Gosh, I wish I'd looked at the paper recently.

Yeah.

Does that mean that you need aromatase to get testosterone in the brain or does it mean that you need the testosterone to become estrogen to go into the brain?

The tea enters the brain and is aromatized there.

Once it gets passed because it doesn't have the alpha-fetoprotein.

This doesn't happen in humans.