TNFRSF11B and Osteopenia: Puerarin decreases bone mass loss (osteopenia) in a concentration dependent manner by stimulating osteoprotegerin (OPG), which promotes osteogenic-specific transcription factors and inhibits Receptor Activator of Nuclear factor-κB (NF-κB) Ligand (RANKL)—a key promoter of osteoclastogenesis [26–28].