Horses are high performance athletes prone to sportive injuries such as tendonitis and desmitis. Fibrous tissue formation with loss of mechanical properties occurs in tendon repair, becoming a therapeutic challenge to overcome. This impels regenerative medicine to develop innovative therapies that enhance tissue regeneration retrieving original tissue properties. Mesenchymal stem cells (MSCs) have been successfully used to develop therapeutic products. They secrete a variety of bioactive molecules that play a pivotal role in tissue regeneration. These factors are released in culture media producing conditioned media (CM). The aforementioned assumptions impelled us to formulate equine synovial membrane stem cells (eSM-MSCs) – the cellular pool that naturally regenerates joint tissue, combined with medium enriched in immunomodulatory factors produced by umbilical cord stroma-derived MSCs (eUC-MSCs), that naturally contribute to suppress the immune rejection in the maternal-fetal frontier. A clinical case of an equine acute desmitis, treated with the abovementioned formulation is presented. Ligament regeneration occurred in a reduced time frame, reducing stoppage time, allowing return to unrestricted competition after completion of a physical rehabilitation program. This study focus was determination of the formulation therapeutic potential and the evaluation of its synergistic effect in an equine desmitis treatment, utilizing the cells themselves and its secretome.