Osteoarthritis (OA) is one of the most common degenerative joint disease for which there is no cure. It is treated mainly with non-steroidal anti-inflammatory drugs to control the symptoms and some supplements, such as glucosamine and chondroitin sulphate in order to obtain structure-modifying effects. Aim of this study is to investigate the effects of L-carnitine, a molecule with a role in cellular energy metabolism, on extracellular matrix synthesis in human primary chondrocytes (HPCs). Dose-dependent effect of L-carnitine on cartilage matrix production, cell proliferation and ATP synthesis was examined by incubating HPCs with various amounts of molecule in monolayer (2D) and in hydromatrix scaffold (3D). L-Carnitine affected extracellular matrix synthesis in 3D in a dose-dependent manner; moreover, L-carnitine was very effective to stimulate cell proliferation and to induce ATP synthesis, mainly in 3D culture condition. In conclusion, L-carnitine enhances cartilage matrix glycosaminoglycan component production and cell proliferation, suggesting that this molecule could be useful in the treatment of pathologies where extracellular matrix is degraded, such as OA. To our knowledge, this is the first study where the effects of L-carnitine are evaluated in HPCs.