Low bone mineral density is one of the primary risks of chronic amenorrhea, and the effects of potentially long-term menstrual disruption on bone mass are serious concerns for individuals with a past or current anorexia nervosa (AN) diagnosis. As such, estrogen therapies are frequently used to address amenorrhea associated with AN. A systematic review of the literature was conducted to examine the effectiveness of estrogen therapies on bone mineral density in women with amenorrhea. Data regarding the effectiveness of oral contraceptives were of low quality and mixed, with the majority of studies finding no benefit of these treatments on bone mineral density. Hormone replacement therapy findings were also mixed, though promising results were found in a study comparing transdermal administration of physiologic estrogen, delivered in developmentally sensitive incremental doses to placebo controls. Though this study suggests a possible role for estrogen therapies in addressing bone density loss in women with AN, in general, more studies are needed. Clinical drawbacks of using these therapies in the treatment of AN, including the loss of menses resumption as a clinical marker for weight and nutritional rehabilitation, must be considered in the decision to use estrogen therapies, particularly given the uncertain effectiveness of most of these treatments.