The present invention relates to novel muteins of human fibroblast growth factor 21 with reduced capacity of O-glycosylation when expressed in yeast compared to wild-type human FGF-21. Both protein and the respective encoding nucleic acid species are disclosed. The invention also embodies vectors and host cells for the propagation of said nucleic acid sequences and the production of said muteins. Also disclosed are methods for treating type 2 diabetes, obesity, or metabolic syndrome.