Collagen, Elastin and Hyaluronic Acid: What They Are and Why They Decline

Almost every aesthetic treatment you will encounter, filler, Profhilo, polynucleotides, microneedling, radiofrequency, chemical peels, PRP, works by targeting one or more of three substances in the skin: collagen, elastin and hyaluronic acid. These are the structural materials that give skin its firmness, its ability to spring back after movement, and its hydration. Understanding what each one does, and what causes each to decline, makes the logic of treatment considerably more legible.

Collagen

Collagen is a protein. It is the most abundant protein in the human body, forming the structural scaffold of skin, tendons, ligaments, bone and connective tissue. In the skin specifically, it lives in the dermis where it is arranged in a dense, interlocking mesh that gives skin its firmness and resistance to stretching.

The primary type in skin is Type I collagen, which provides tensile strength. Type III collagen, sometimes called reticular collagen, is softer and contributes more to the skin’s pliability. Both are produced by cells called fibroblasts.

Collagen production peaks in early adulthood and then declines at an estimated rate of around one per cent per year from the mid-twenties onwards. The decline is accelerated significantly by ultraviolet exposure, which triggers enzymes called matrix metalloproteinases that actively break down collagen, and by smoking, chronic inflammation and sustained high blood sugar levels, which cause a process called glycation that cross-links and stiffens existing collagen fibres.

What this means for treatment: most aesthetic treatments that claim to improve skin firmness work by stimulating fibroblasts to produce new collagen. SkinPen microneedling creates controlled micro-channels that trigger a repair response and new collagen formation. Fractora and Forma radiofrequency deliver heat energy that causes controlled thermal injury and collagen remodelling. PRP, iPRF and polynucleotides each stimulate fibroblast activity through different biological pathways. Chemical peels accelerate cell turnover and prompt the underlying dermis to respond with new structural support.

None of these treatments adds collagen directly. They trigger the body to produce more of its own.

Elastin

Elastin is what allows skin to spring back after movement. When you smile, squint or raise your eyebrows, the skin deforms briefly and then returns to its resting position. In younger skin, that return is almost immediate. As elastin declines, the return slows, and eventually the deformation becomes a more permanent crease.

Unlike collagen, which continues to be produced throughout life (even if at a declining rate), elastin is produced primarily during foetal development and early childhood. Very little new elastin is made in adult skin. What you have by early adulthood is largely what you are working with, and it degrades gradually through UV exposure, environmental damage and the mechanical stress of a lifetime of facial movement.

This makes elastin loss more irreversible than collagen loss from a treatment standpoint. Radiofrequency treatments, Forma and Fractora, do stimulate some elastin remodelling through the heat response, which is one reason they remain a useful option for improving skin resilience alongside firmness. But the realistic expectation from any non-surgical treatment is improvement in the visible signs of elastin loss rather than restoration of what was there at twenty-five.

Hyaluronic acid

Hyaluronic acid is not a protein. It is a polysaccharide and its primary role in skin is water retention. It has a remarkable capacity to attract and hold water, approximately a thousand times its own weight, and this water-binding function is what creates the plump, hydrated quality of well-functioning skin.

Hyaluronic acid is produced continuously by fibroblasts and other cells, but it turns over rapidly. The total amount present in skin declines with age and is significantly reduced by UV exposure, which degrades it more aggressively than either collagen or elastin.

When skin looks dull, flat or dehydrated rather than sagging or wrinkled, hyaluronic acid depletion is often a primary driver. This is the rationale for Profhilo: a high-concentration injectable hyaluronic acid that spreads through the deeper skin layers, binds water extensively, and also stimulates fibroblasts to produce more of their own collagen, elastin and hyaluronic acid. It is not adding volume in the way that filler does. It is restoring the hydrating medium that makes skin look and feel more alive.

Why this matters when choosing treatment

Most skin quality complaints fall into one of three categories: loss of firmness (primarily collagen), loss of resilience and spring (elastin), or loss of hydration and surface quality (hyaluronic acid). Many patients present with elements of all three, which is why combination treatment plans are common.

Where firmness is the primary concern, collagen-stimulating treatments are most appropriate. Where the skin looks dehydrated or lacks surface quality, hyaluronic acid-based treatments are the logical starting point. Where both are present, the plan addresses both in sequence or in parallel.

Understanding which of these is driving your concern makes it easier to evaluate what you are being recommended at consultation and why.

Frequently asked questions