Cathepsins are a family of lysosomal proteases which function in several biological processes such as protein degradation, tissue remodeling, immune response and progression of cancer. Among humans, there exist a group of 15 cathepsins with names ranging from Cathepsin A to Cathepsin Z which are examined here in this review for their structure, function and therapeutic perspectives. The Protein Data Bank (PDB) was used to acquire the human cathepsin 3D structures and modeled with AlphaFold2, a state-of-the art deep learning-based method. We explain what the specificities among cathepsin subtypes are for preferred substrates and target organs and include their implication in pathological diseases such as cancer and osteoporosis. In addition, we review the latest research on cathepsin inhibitors as potential therapeutic targets for various human diseases. This review aims to provide an updated and comprehensive understanding of human cathepsins and their potential applications in medicine.