Testosterone Treatment for Erectile Dysfunction and Multiple Sclerosis

Volunteers will be treated weekly with Xyosted 75 mg (given subcutaneously) for 3 months during which they will have 3 study visits, 6 weeks apart. The Baseline visit will include providing a blood sample, completing questionnaires, receiving training on the Xyosted auto-injector, and undergoing a rectal exam for participants 55 years and older. Visits 2 and 3 will also include collecting a blood sample and completing questionnaires. At Visit 3, the rectal exam for those age 55 years and older will be repeated.