Peptide nanotubes are promising bio-inspired self-assemblies with a wide range of envisioned applications. The present review addresses the recent advances in their fundamental comprehension and mechanistic aspects of their latest downstream uses. Through well-documented examples, including the Lanreotide peptide monodisperse nanotubes, the molecular organisations and interactions underlying such well-defined hierarchical nanoarchitectures are in particular examined. The kinetic and thermodynamic aspects of the corresponding self-assembly processes are also considered, especially the intriguing mechanism of nanotube wall closure. The recently unravelled Lanreotide self-assembly mechanisms have revealed, for instance, the limiting role of electrostatic repulsion in this critical step. Within the numerous applications currently explored, particular attention is given to promising inorganic deposition processes using peptide nanotubes as scaffolds. In exceptional cases, inorganic nanotubes with tunable diameters could be synthesised viapeptide-based template-directed synthesis combined with peptide chemical design. Such examples highlight the importance of advanced molecular and mechanistic understanding of peptide nanotubes, particularly for bottom-up chemical design strategies and downstream applications. Although incomplete, the current fundamental comprehension of peptide nanotubes has already shown its potential by opening up new valuable routes in the field of biomimetic soft matter.