Solid-phase peptide synthesis, the standard method for obtaining peptides. The peptide, linked by its C-terminus to a carrier, an inert, insoluble but swellable polymer, is elongated stepwise. The method can be fully automated. Fmoc- and Boc-SPPS differ in the choice of the temporary (= Boc or Fmoc) and permanent (side-chain) protecting groups. The type of Nα-blocking group determines the options for side-chain protection and the conditions of final cleavage (removal of the permanent protective groups and splitting from the carrier). Fmoc-SPPS is considered the milder method.