Your skin has a support material inside it called collagen. Think of it like the scaffolding that holds a building up. Collagen is what keeps skin firm, smooth, and bouncy.
Your body makes collagen with the help of a hormone called oestrogen. During menopause, your body makes a lot less oestrogen. Less oestrogen means your skin makes less collagen. And less collagen means the "scaffolding" gets weaker.
This isn't a new idea. Doctors first studied it back in 1985. Researchers at King's College Hospital in London measured skin thickness and collagen in postmenopausal women. What they found was clear: the longer it had been since a woman's last period, the less collagen her skin had. It wasn't about how old she was. It was about the hormone drop.
Since then, more research has put a number on it. Skin can lose up to 30% of its collagen in the first five years after menopause. After that, it keeps dropping slowly — about 2% every year.