H3R was selected as target for several reasons: (i) ligand data is publicly available, (ii) crystal structure is currently still missing, (iii) H3R is an important drug target discussed for many severe diseases including Alzheimer’s disease, schizophrenia, Parkinson’s disease, narcolepsy, pain, and obesity among others [13,14] and (iv) a recent study of us revealed that H3R and melanin-concentrating hormone receptor 1 can be inhibited by the same ligand which could be potentially used in obesity treatment [15]. Here, HRH3 is linked to obesity due to melanocortin 4 receptor deficiency.