Extrinsic vs. intrinsic ageing – what’s the difference?

Ageing of the skin is not solely chronological, because there are several other contributing factors. These fall into either intrinsic or extrinsic categories.

What is intrinsic ageing?

Intrinsic, or chronological ageing, is the inevitable genetically determined process that naturally occurs. Intrinsic ageing is determined by each person’s individual genetic clock and is affected by the degenerative effects of free radicals and the body’s inability to perfectly repair their damage.

Over time cells, tissues and vital organs ‘rust’ or deteriorate. These internal changes to the muscle, fat and bones are not as visible as the signs of ageing on skin, the external organ.

Intrinsic ageing is a continuous process that usually begins in the mid-20s but may not become evident for decades. In a person’s 20s collagen production begins to slow and elastin has a bit less spring. Dead skin cells do not shed as quickly and turnover of new skin cells decreases.

What are the signs of intrinsic ageing?

The apparent signs of intrinsic ageing include the loss and descent of underlying fat, leading to hollowed cheeks and eye sockets, as well as loss of firmness and sagging skin as the bones shrink away from the skin due to bone loss.

What is extrinsic ageing?

The extrinsic, or preventable environmental factors that magnify intrinsic ageing, often act together with the normal ageing process to prematurely age skin.

Most premature ageing is caused by sun exposure, though others are repetitive facial expressions, gravity, sleeping positions and smoking.

What are the signs of extrinsic ageing?

Age-associated changes including thinning, laxity, fragility and wrinkles. In addition, sun exposure leads to dyspigmentation, premature wrinkling, telangiectasia and actinic elastosis.