Microneedling — also known as percutaneous collagen induction (PCI) — creates controlled micro-injuries that trigger a healing cascade producing more collagen than it destroys. Growth factors released by platelets (PDGF, TGF-α, TGF-β) initiate three well-established phases.
Phase 1: Inflammation (0–3 days)
Neutrophils and macrophages migrate to the lesion site, releasing additional growth factors (FGF, EGF, VEGF). This phase is essential — suppressing it with NSAIDs reduces results.
Phase 2: Proliferation (3–14 days)
Fibroblasts synthesise type III collagen (provisional) and new elastic fibres. Keratinocytes migrate to restore epidermal continuity. Active ingredients applied during treatment act most powerfully in this phase.
Phase 3: Remodelling (14 days – 2 years)
Type III collagen is replaced by stable type I collagen. Results continue improving for up to 12 months after completing the protocol.