Why people often say that 25 is the age when early ageing and decline begin?

为什么人们常说25岁是进入初老、衰老开始的年龄？

Why do people often say that 25 is the age when early ageing and decline begin?

最主要原因就是胶原蛋白的流失

The main reason is the loss of collagen

胶原蛋白流失伴随而至的就是：

The loss of collagen is accompanied by:

细胞活跃度下降、细胞分化能力下降、新城代谢越来越差

decreased cell activity, decreased cell differentiation ability, and increasingly poor metabolism.

为什么25岁是衰老的始点？

Why is 25 the starting point of ageing?

一般来讲

Generally speaking

人类的骨骼在25岁左右会基本定型不再生长

human bones are basically fully formed by the age of 25 and do not grow any further.

此时脊髓的成纤维细胞也停止生成Ⅲ型胶原蛋白

At this point, the fibroblasts in the spinal cord also stop producing type III collagen.

Ⅲ型胶原于皮肤的意义就像是水对枯树的意义

Type III collagen is to the skin what water is to a dry tree

它是维持细胞活跃度和细胞分化速度的一个基础

It is fundamental to maintaining cell activity and cell differentiation rates.

同时Ⅰ型、Ⅳ型、Ⅴ型、Ⅶ型、XVII型也在流失

At the same time, types I, IV, V, VII, and XVII are also being lost.

伴随而来的皮肤的变化：

Accompanying skin changes:

皮肤干燥、纹理粗糙、保湿能力变差、

光泽度下降、细腻度下降、

炎症反应增加、皮肤脆弱易损伤、

伤口愈合变慢、修复能力降低、

弹性减弱、皮肤松弛、皱纹增多等等

Dry skin, rough texture, reduced moisture retention,

decreased radiance, reduced smoothness,

increased inflammatory response, fragile and easily damaged skin,

slower wound healing, reduced repair capacity,

weakened elasticity, sagging skin, increased wrinkles, etc.