Collagen is the skin’s “steel reinforcement”; elastin is the “spring”. Understanding how they are lost is the key to choosing an effective anti-ageing strategy.

Fibroblasts are the most critical cells in the dermis, responsible for synthesising collagen, elastin and hyaluronic acid. The essence of anti-ageing is to keep activating fibroblast activity. What is commonly called “collagen” is in fact a composite network: collagen is like the steel reinforcement in a building, providing support and toughness; elastin gives skin its elasticity, ensuring it can return to shape after stretching; reticular fibres are the earliest scaffolding framework.
| Property | Type I | Type III |
|---|---|---|
| Structure | Thick, tough fibre bundles | Fine, soft, elastic reticular fibres |
| Function | Provides support and toughness | Responsible for elasticity and softness |
| Ageing change | Total amount is lost; structure becomes disordered | Lost more rapidly; the proportion drops significantly |
With ageing, Type III collagen is lost rapidly and replaced by Type I, leaving skin that is “thick” yet “hard”, without a soft feel, with fine lines and laxity coexisting.
Injectable treatments (targeted induction): collagen biostimulators such as Sculptra (PLLA) use microspheres as a biological signal, continually stimulating new Type I collagen; results appear progressively and may last more than two years. Ellansé (PCL) has a dual “immediate plus long-acting” mechanism, promoting new Type I and Type III collagen at the same time.
Energy-based devices (full-field activation): Thermage FLX uses monopolar radiofrequency to heat the dermis, immediately contracting lax collagen and, over the following months, stimulating abundant new Type I collagen — suitable for mild-to-moderate laxity. Fractional laser/radiofrequency creates fine heated zones, triggering a wound-healing response and strongly promoting multiple types of new collagen.