[jxcole]

Why would that make it less reversible? Honestly it's not like it was ever easy to reverse DNA damage. Reversing other kinds of damage might be harder, but unless you have more information it's not clear that it _must_ be.

[aeternum]

If you have a skin cell that incorrectly differentiated into a mole, how do you reverse it?

You can't just fix the DNA, it must also figure out whether it should become a hair follicle or one of the many subtypes of cells that make up your skin layers. We know that this differentiation seems to be controlled by ion/electrical signals early in life.

So a key question is: Why does differentiation accuracy seem to degrade with aging, and is there anything we can do to stop it?

CRISPR is pretty good at fixing DNA, we definitely need to optimize our use of that tool but at least there's a path. We really don't have a clear path to fix the differentiation/epigenome problem.

[steveylang]

It's theoretically more reversible, but dependent on identifying epigenetic factors that can practically be counteracted or at least lessened (and don't have significantly adverse side effects.)

In reality, it will probably just mean a bunch of snake oil 'epigenetic health supplements' on the shelves that don't actually do anything.