Despite the ubiquity and regularity of the amyloid state, the fibrils of a given protein can have multiple polymorphs, differing primarily in the arrangement of β-strands within a layer. Amyloid elongation is the prototypical aggregation reaction and the dominant pathway for producing amyloid mass. The prevailing polymorph is defined by the relative elongation rates of nucleated species as well as the thermodynamic stabilities i.e. the forward and backwards reactions along the elongation pathway. Attempts to therapeutically target amyloid aggregation is currently hindered by poor understanding of the relevant aggregation pathways and developing a full understanding of the microscopic steps of aggregation is of significant value to the field .