[scientizscht (OP)]

Hello

You know when it's cold and you get skin like chicken?

What's the molecular basis of this?

[evan_au]

I think you are referring to "goose bumps"?

It is due to muscles under the skin causing the hairs to stand up. But it doesn't have a big effect in humans, since we don't have very much hair on most of our bodies.

A molecular-level explanation will be less comprehensible than a higher-level explanation, such as you will find here:  https://en.wikipedia.org/wiki/Goose_bumps