How Regenerative Injectables Work: PLLA, PDRN and CaHA

Regenerative injectables are not interchangeable. Each biomaterial works through a distinct mechanism, which is why treatment planning matters. Here is a plain-language overview of the three most established families.

PLLA — gradual collagen stimulation

Poly-L-lactic acid microspheres form a stable scaffold in the tissue and activate dormant fibroblasts. Over weeks, those fibroblasts synthesise new Type I and Type III collagen, gradually rebuilding the extracellular matrix. The effect is progressive and natural, developing over months rather than instantly.

PDRN — repair and skin quality

Polydeoxyribonucleotide, derived from salmon DNA, is taken up by cells where it modulates inflammation and activates repair signalling. It supports fibroblast proliferation and healthy tissue structure, making it well suited to barrier repair, post-procedure recovery and overall skin quality.

CaHA — immediate support plus regeneration

Calcium hydroxyapatite microspheres, suspended in a gel carrier, provide immediate structural support on injection. As the carrier degrades, the microspheres stimulate new collagen before being metabolised naturally into calcium and phosphate. CaHA therefore combines an instant contouring effect with longer-term biostimulation.

The takeaway

Because each material behaves differently, the most effective outcomes often come from matching the right material — or combination — to the patient's goals, rather than relying on any single product.