What is Mesotherapy? Mesotherapy has been used in Europe since 1952 when it was invented by the French physician Dr. Michel Pistor for pain management. It is the injection of a mixture of FDA approved medications, vitamins and minerals intro the mesoderm, the layer of fat and connective tissue just under your skin. This mixture may differ depending on the condition and area being treated. Mesotherapy has a number of medical applications that include weight loss, sport body contouring, face and neck rejuvenation and cellulite reduction.