To evaluate the suitability of DIPSI-3 for use in sensitivity-enhanced solid-state NMR experiments, we recorded 2D hnCACX spectra of 13 C 15 N labelled MLF at 55 kHz MAS. We tested two different approaches for DIPSI-3, with and without 90 degree pulses before and after the DIPSI-3 mixing. The difference between these approaches is that if we include 90 degree pulses with the phase x and -x, while the DIPSI-3 spin-lock is along y (from now on referred to as zTOCSY), the two components that are preserved are Z and X and if we don't include the 90 degree pulses (from now on referred to as xyTOCSY) the preserved components are X and Y. Using zTOCSY (orange spectrum in Fig. ) with 16.3 ms mixing time at a nutation frequency of 10 kHz results in a spectrum where cross-peaks with the C carbons appear for all expected side-chain carbons. With the xyTOCSY approach all expected peaks also appear (brown spectrum in Fig. ), but some mirrored peaks with opposite phase compared to the real peaks can also be observed (grey peaks with red crosses). To further explore the appearance of mirrored peaks we recorded the same spectrum using TOBSY (C948 1 ) (green spectrum in Fig. , from now on referred to as C9) that allows for non-negligible cross-transfer (e.g X-Y, X-Z etc.). C9 shows efficient transfer to all expected side-chains (indicated with black crosses) and additionally strong mirrored peaks (indicated with red crosses) when the spectrum is recorded in a sensitivity-enhanced fashion. In standard experiments unwanted cross-transfers can be compensated for by using a z-filter, which is typically done for applications of C9 sequences . However, applying a z-filter is not compatible with sensitivity-enhanced experiments since then only one component would be preserved. During the preparation of this manuscript a new approach using dipolar-based C- C mixing (homonuclear SPEPS) was published . In addition to backbone homonuclear transfers ( 13 C-13 CO, CO-13 C), a mixing sequence for C- C transfers (homonuclear SPEPS CA-CB , from now on referred to as hSPEPS) suitable for sensitivity-enhanced experiments was reported. We include this mixing sequence as a dipolar based alternative, instead of DREAM that is not compatible with sensitivity-enhancement. As expected, hSPEPS mixing leads to a spectrum with strong C-C cross-peaks without any mirrored peaks. A comparison of the transfer efficiency for the different mixing sequences (Fig. ) reveals that hSPEPS performs best for C-C transfers, while C9 performs best for other side-chains (slightly better than zTOCSY followed by xyTOCSY). The phenylalanine of MLF was not included in the comparison since the C offset for the indirect dimension is at the C chemical shift of the phenylalanine leading to that mirrored peaks will overlap with real peaks and a reliable characterization of the peak intensities is not possible. Note that hSPEPS also allows for transfer to carbons further down the side-chain if a longer mixing time is used , but with lower efficiency compared to TOCSY and C9 (see SI figure ). The main reason for unwanted cross-transfers resulting in mirrored peaks appears to be inhomogeneity of RF pulses or rather the robustness of the mixing sequences towards RF inhomogeneity. This was realized based on SIMPSON simulations of the transfer efficiencies for transfers between all possible components at different mixing times. RF inhomogeneity was tested by varying the RF power in the simulations by 10% from the ideal conditions. Fig. shows a bar plot summarizing the results from the simulations of DIPSI-3 and Fig. shows examples of the results from the full simulations. The transfer efficiency pattern for the X and Z components are very similar (CZ to CZ and CX to CX). The unwanted CX to CZ and CZ to CX cross-transfers are minimal while the CX to CY and CY to CX cross-transfers are non-negligible. This becomes clear when non-ideal RF powers are applied (red and yellow bars and lines in Fig. ). The simulations agree well with the experimental data regarding unwanted cross-transfers resulting in mirrored peaks, see supplementary information for the results from all simulations of DIPSI-3 (SI Fig. ), C948 1 (SI Fig. ) and hSPEPS (SI Fig. ). A comparison of the intensities of the peaks in the zTOCSY and xyTOCSY spectra (Fig. ) shows that the sensitivities of the C-CX peaks are not strongly affected by unwanted cross-transfers in MLF, although any loss of sensitivity and the appearance of mirrored peaks would be problematic for protein chemical shift assignments.