Dr. David Sinclair

When they're 70, they still look 50 or less.

So it is a good indicator.

It's not perfect because you can, like me, grow up in Australia and accelerate the aging of your skin.

But in general, how you look.

No one's ever dyed from gray hair, but overall you can get a sense just from the ability of skin to hold itself up, how thin it is, the number of wrinkles.

Yes.

Really good question.

So those chemicals we can measure, it's also known as the Horvath clock.

It's the biological clock.

It's separate from your chronological age.

There are some people that are 10, 20 years younger than other people biologically.

And it turns out if you measure that clock from birth or even before birth, if you look at animals, there's a massive increase in age based on that clock early in life.

So you're right.

So that's a really important point that you have accelerated aging during the first few years of life, and then it goes linear towards the rest of your life.

But there's another interesting thing you brought up, which is that we're finding that the genes that get messed up, that get scratched,

that are leading to aging are those early developmental genes.

They come on late in life and just mess up the system.

And they seem to be particularly susceptible to those scratches.

So what's causing the scratches?

Well, we know of a couple of things in my lab, we figured out.