Dr. Abud Bakri

The rate of decrease varies dramatically from person to person.

So we call this thymic involution.

So from the moment puberty starts till you die, your thymus is slowly shrinking.

That really happens in your 20s and 30s, the majority of that, under the pressure of androgens, estrogens, progestins, and corticosteroids.

Those are driving a lot of the shrinkage.

So the...

Yes.

So like castration will undo some of the thymic involution.

Pregnancy is a great time to involute your thymus, which makes sense because you don't want to be having an autoimmune attack against the baby or an immune attack against the baby.

Do women's thymus disappear after pregnancy?

They involute.

And then we'll regrow during the breastfeeding period under the influences of growth hormone and prolactin.

So hibernating animals will have a dramatic shrinkage of the thymus during hibernation and then a regrowth during the feeding window.

Yeah, there's an interesting study, TRIM trial from Dr. Greg Fahey.

He's doing a study where he's giving a cocktail of growth hormone, metformin, and DHEA.

Gave that for 12 months and had the thymus size increase on imaging.

The amount of CD4, CD8 T cells increased and the ratio of which improved.

And then some of the markers that would show like immune cell exhaustion, like PD-1 and all these different aspects of T cell dynamics also improved.

So they're trying to use growth hormone to regrow the thymus.

So thymus and alpha-1 is part of this thymic family of hormones that gets secreted.