The safety of mesenchymal stem cell therapy for osteogenesis imperfecta has been demonstrated previously. However, it is unknown how the trophic effects are mediated by stem cells. In the present commentary, we bring to the attention of readers the recent report by Infante et al in the journal of clinical and translational medicine. The TERCELOI clinical trial presented the possible paracrine effect of transplanted MSCs in vitro and in vivo using proteomics and transcriptomic analysis. This novel finding adds new knowledge in the field of regenerative medicine. However, the scarcity of solid evidence in growth warrants a more thorough discussion.