Mesoporous silica nanocarriers (MSNs) have emerged as significant candidates in the pharmaceutical industry for drug delivery systems, suitable for a wide variety of drugs. Absorbing the active pharmaceutical ingredients (APIs) into the pores can be beneficial in several ways. The narrow pores may stabilize the APIs in an amorphous state, thereby improving its aqueous solubility and providing protection for the encapsulated drug against various factors in the human body, including enzymatic or chemical degradation, which enhances the bioavailability of the product. Beside the overview of their main characteristics, the present review focuses on the recent findings on MSNs form therapeutic and drug formulation perspective, including functionalization possibilities, as the size and surface of the particles influence the interactions with the cell membrane; therefore, the epithelial permeability of and release rate from the carrier, and may offer even targeted delivery in an organ-, tissue- or cell-specific manner, improving the therapy, also avoiding drug-related side effects.