alpha-helical CRF (9-41) is a corticotropin releasing factor receptor (CRF) antagonist with Ki values of 17, 5 and 0.97 nM at human CRF1, rat CRF2alpha and mouse CRF2beta receptors respectively. alpha-helical CRF (9-41) decreases anxiety like behaviour in the conditioned fear test and reverses the potentiation of startle amplitude produced by administration of CRF in anxiety models. alpha-helical CRF (9-41) pre-treatment blocks CRF induced food intake inhibition.