Most of us think of our skin as something external. The part we stress about the most. How it looks, what other people see, whether it's holding up. Something to maintain.
But your skin is not just on the outside. It is the largest living organ you have, and every minute of the day it is doing biology: making proteins, defending itself, repairing, signalling, adapting. Once you see it that way, skin health stops being a question of what you put on and starts being a question of what your biology is doing, and what you can do to help it.
What you were born with
Some of how your skin behaves was decided before you were. Your genes set the baseline. How much collagen and elastin you make and how well you make it. How thick your skin is. How much pigment it holds. How reactive it is to the world. How quickly it recovers from a bad week.
This is why two people the same age can have skin that looks a decade apart, and why the products that changed your friend's skin did nothing for yours. You are not working from the same starting point.
Genes are not a verdict, though. They are a predisposition. They set the range your skin can work within. Where you sit inside that range is largely down to something else.
What the world does to it
Scientists have a name for everything your skin meets over a lifetime: the exposome. Sunlight, pollution, smoke, temperature, what you eat, how you sleep, how stressed you are. Studies of identical twins, who share the same genes, show how much this matters. Where one twin smoked, or spent more years in the sun, their skin looked measurably older than their sibling's. Same biology. Different exposure. Different result.
Here is what those exposures actually do. They create oxidative stress, and oxidative stress damages proteins. Your skin is built from proteins: collagen for structure, elastin for spring, keratin for resilience, and thousands of enzymes and messengers keeping the system running. Together they are your skin's proteome, and it is where our research begins. When the exposome damages those proteins, skin loses function. It gets duller, less elastic, less able to hold its barrier. That is what ageing looks like from the inside. Not time passing. Function being lost.
Why this is good news
If skin ageing were only about time, there would be nothing to do but wait. It isn't. A large part of it is about exposure and response, and both of those are things you have a say in.
Our approach to skin health starts there. We don't think of skin as something to correct after the damage shows. We think of it as a living system to defend and to help recover, day after day, so that it holds onto its function for longer. And we measure what we do at the level of the protein itself. In the laboratory, we track protein carbonylation, the chemical signature oxidative stress leaves on skin's proteins, in human skin samples exposed to environmental stress. Unlike a promise, a biomarker can be measured before and after.
You can't choose your genes. You can choose how you treat the biology they gave you. That is agency, and it is the whole point of skin longevity. Not turning back anything. Taking care of what is still working, so it keeps working. Age your way.