Topical minoxidil (MXD) is frequently used as therapy for alopecia. In this study, a new MXD molecular salt formed by MXD and the 2,4-dihydroxybenzoic acid (24HA) were prepared and characterized. The nature of the MXD/24HA salt was studied using infrared spectrometry, single-crystal and powder X-ray diffraction, X-ray photoelectron spectroscopy, Hirshfeld surface analysis, and configuration interaction calculations. The theoretical results and the experimental data show that the proton transfer accompanies the formation of the MXD/24HA salt. The resulted MXD/24HA salt crystallizes in themonoclinic space group P21/c. The in vivo assessment with the hair growth model in mice reveals that the MXD/24HA salt is superior to the raw MXD. Thus, the MXD/24HA salt can potentially be a candidate drug for hair loss. The combination of theory and experiment enables an innovative methodology to understand the differences in structure and properties of pharmaceutical salts.