Peter Attia, M.D.

But to cite one study that I've talked about many times in the past, it's about a 13-year-old study that took a large group of men, chemically castrated them all.

and then made them replete with different doses of testosterone with and without anastrozole.

So this study basically gave men, I think there were five groups of testosterone and with and without anastrozole.

So for folks listening, anastrozole would inhibit the conversion of testosterone to estradiol.

That's right.

It's an aromatase inhibitor.

So you have from low to high, five levels of T with and without estrogen.

It was in the New England Journal of Medicine.

I don't remember who published it.

We'll link to it in the show notes.

The question was, what did these 10 groups, how did they differ with respect to body composition, mood, affect, sexual desire, all these sorts of things?

I don't remember if bone density was studied.

It might not have been a long enough study.

It's been so long since I've looked at it.

But here was the big takeaway.

The TLDR was by far the best producing outcome, was the highest T with high estrogen.

Everything, for body composition, mood, you name it.

The learning to me, it wasn't surprising that higher testosterone was better than lower testosterone for all the metrics that were measured.

The surprising insight at the time, again, we now, I think, understand this much more.

But for me at the time, the surprising insight was more estrogen was better than less for men, not just with respect to how they felt, but even body composition.