Anorexia Nervosa affects 0.5-1% of college-age women in the US and is associated with a number of significant medical conditions including bone loss. A majority of women with anorexia nervosa have bone loss and 50% have bone mineral density measurements greater than 2 standard deviations below normative means. Bone loss in anorexia nervosa is characterized by a decrease in bone formation, therefore therapy with an anabolic agent may be an effective treatment approach. In a randomized, single-blinded, placebo-controlled trial, we will study the effects of parathyroid hormone on low bone mass in anorexia nervosa, specifically looking at the effects of parathyroid hormone on bone mineral density (primary outcome).