Concentrated hyaluronic acid capsules. Hyaluronic acid is a high molecular weight linear polysaccharide widely present in the connective tissues of organisms, including humans. It is primarily concentrated in the synovial fluid (which lubricates joint surfaces, protecting them from wear), cartilage, the vitreous humor of the eye, and the umbilical cord. Hyaluronic acid is capable of binding many water molecules, achieving a high degree of hydration. For this reason, given its remarkable thickening properties, hyaluronic acid is essential for maintaining the correct level of hydration, turgidity, plasticity, and viscosity of the extracellular matrix (ECM).