We find that the ThT intensity of the shaven fibrils decreases by over 50 % within the shaving phase (100 min). Additionally we find that the shaven fibrils are more prone to higher order assembly (flocculation) than non-shaven fibrils, inducing larger spatial variability in ThT intensity across the microcapillary, compared to the sample without pK treatment (Fig. ). We quantify the degree of flocculation through the spatial standard deviation of fluorescence intensity of the entire field of view of the capillary. This higher order assembly is likely to affect the accessibility of the fibril ends for monomer. The strong tendency of shaven α-synuclein fibrils to undergo higher order assembly is unsurprising, given the highly negatively charged and disordered C-terminal tail is removed, which otherwise provides electrostatic and steric repulsion of other molecules. It is reasonable to assume that removal of the fuzzy coat not only affects the higher order assembly of fibrils and interactions with small molecules, such as ThT, but surface interactions with the monomeric protein as well, as charges are removed and the hydrophobic core becomes more accessible. These various effects conspire to render a quantitative comparison of the intrinsic elongation rates of intact and shaven fibrils in such bulk solution assays very challenging. In addition, we can-not fully exclude residual activity of the inhibited PK in such a bulk solution assay.