Ejiao as a preventive agent for osteoporosis - a scoping review of current evidence

Ejiao, a traditional Chinese medicinal product derived from donkey's hide, has long been used to promote blood formation and treat various ailments. Recently, growing pharmacological evidence has suggested that Ejiao and its formulations may also possess bone-protecting properties, making it a potential candidate for preventing and treating osteoporosis. This scoping review aims to summarise the current scientific evidence on the anti-osteoporosis potential of Ejiao and its formulations in osteoporosis prevention. A comprehensive literature search was conducted using PubMed, Web of Science, Scopus, and China National Knowledge Infrastructure up to October 2024. Primary studies published in English or Mandarin, regardless of study design, that investigated the effects of Ejiao on bone in vivo or bone cells in vitro were included. A total of 22 studies were included, comprising five studies on Ejiao alone and 17 studies on Ejiao-based formulations. The findings indicated that Ejiao alone enhanced osteoblast differentiation by increasing alkaline phosphatase synthesis and reducing bone remodelling markers in ovariectomised rats. However, its direct effect on bone mineralisation and density remains uncertain due to the absence of an exogenous mineral source. In contrast, Ejiao-based formulations, such as calcium-Ejiao oral liquid and Donkey-hide glue reinforcing bone oral solution, demonstrated more pronounced bone-protective effects, including improving bone density, enhancing bone repair, and supporting vitamin D metabolism in both animal models and clinical studies. These findings suggest that while Ejiao alone may promote osteoblast activity, its role in osteoporosis management may be more effective when combined with essential minerals. Further long-term studies and human clinical trials are needed to clarify its therapeutic potential and underlying molecular mechanisms.