Despite the thousands of exoplanets and substellar objects discovered to date, numerous questions about the mechanism of the formation and evolution of brown dwarfs and planets remain unknown, mainly because the lack of a statitically significant number of young exoplanets and substellar objects known with well characterized physical properties, in particular their masses. The main scientific objective of the IAC is to investigate the formation and evolution of substellar objects. To reach this goal, we will search and characterize exoplanets and brown dwarf companions around young and metal poor stars, determine their dynamical masses using radial velocity (high resolution spectroscopy), and astrometric (high resolution images) techniques, and study the evolution of their physical properties with time. Our specific objectives are: 1) Commissioning and first science of the GTC Adaptive Optics (GTCAO) system, GRANCAIN camera and Laser Guide Star (LGS) system, 2) Physical properties of substellar companions around young and metal poor stars, 3) Search and characterization of halo brown dwarfs, 4) Masses and radii of planets orbiting young stars: towards the study of the Earth in time, 5) Validation and mass determination of exoplanets discovered by TESS.