الكولاجين
Collagen is the protein that gives skin its structure and firmness and the one that declines steadily with age. Topical collagen skincare supports the appearance of plump, firm, hydrated skin, working largely at the surface (the collagen molecule itself is too large to penetrate deeply, which is worth knowing honestly). For visible firmness over time, collagen formulas are best combined with ingredients that support the skin's own collagen-related processes, like peptides and vitamin C. Use as a serum or cream within a consistent routine, with daily SPF to protect existing firmness.