Most M.D.-Ph.D. students complete the requirements for the dual degrees within 7 or 8 years. Some students complete the program in 6 years, while others may take longer than 8 years. The variation is due to the amount of time required to complete Ph.D. requirements, because one cannot predict the progress of research or the amount of time needed to develop into an independent investigator, the primary goal of Ph.D. training.
Note that the average time to complete a biomedical Ph.D. in the United States is about 6 years. Thus, if pursued independently, obtaining a dual degree would take about 10 years. By integrating the didactic components of training, dual-degree students complete the program in 7 or 8 years on average.