 JAK inhibitors are under development for the treatment of psoriasis, atopic dermatitis, rheumatoid arthritis, polycythemia vera, alopecia, essential thrombocythemia, ulcerative colitis, myeloid metaplasia with myelofibrosis and vitiligo.Examples are tofacitinib, baricitinib, upadacitinib and filgotinib (GLPG0634), the latter is currently under development by the Belgian firm Galapagos.In 2014 researchers discovered that oral JAK inhibitors, when administered orally could restore hair growth in some subjects and that applied to the skin, effectively promoted hair growth.