Melatonin has been shown to help regrow hair in approximately 60 percent of Pomeranians with follicular arrest. We hypothesize that melatonin works by inhibiting estrogen receptors on hair follicles. Sixteen neutered Pomeranians will be enrolled. Dogs will be evaluated by veterinarians and not necessarily by the principal investigator. They will be diagnosed with follicular arrest by clinical signs and ruling out hypothyroidism and hyperadrenocorticism. A biopsy will be taken from an alopecic area. The histopathology should support the diagnosis of follicular arrest and eliminate diseases that could mimic this condition (sebaceous adenitus, color dilution alopecia, etc.). A second biopsy will be obtained from a similar location after 3 months on melatonin. The biopsies will be evaluated for number of hair parameters. Immunohistochemical detection of estrogen receptors will also be performed. Using morphometric analysis, we will compare estrogen receptor numbers after three months of melatonin to baseline for each dog and numbers of estrogen receptors in dogs with hair regrowth on melatonin to those that did not regrow hair.