The present invention is directed to novel 1,2,4-thiadiazol-2-ium derivatives useful as agonists or antagonists of the melanocortin receptor. More particularly, the compounds of the present invention are useful for the treatment of metabolic, CNS and dermatological disorders such as obesity, impaired oral glucose tolerance, elevated blood glucose levels, type II diabetes, Syndrome X, diabetic retinopathy, spinal cord injury, nerve injury, acute neurodegenerative disorders, chronic neurodegenerative disorders, plexopathies, male erectile dysfunction, dry eyes, acne, dry skin, aged skin, seborrheic dermatitis, rosacea, excessive ear wax, meibomian gland disorder, pseudofolliculitis, yeast infections, dandruff, hidradenitis suppurativa, ocular rosacea and eccrine gland disorder.