A Standard Herbal Formula, CGAC, Attenuates Bone Loss by Normalizing Low-Bone Turnover Stagnation in an Orchiectomy-Induced Mouse Model.

Background/Objectives: Osteoporosis is a progressive systemic skeletal disease, with male osteoporosis emerging as a critical global concern due to high morbidity and mortality from fractures. This study investigated the anti-osteoporotic potential of CGAC-a herbal mixture of Cervus elaphus Linnaeus, Glycine max (L.) Merr., Angelica gigas Nakai, and Cnidium officinale Makino-and its underlying mechanisms in an orchiectomized (ORX) mouse model. Methods: C57BL/6J mice underwent ORX for 8 weeks, followed by CGAC administration (250 and 500 mg/kg) for an additional 8 weeks. Molecular mechanisms were further validated using MG63 osteoblastic and RAW 264.7 osteoclast assays. Results: ORX induced severe osteoporotic phenotypes, including significant reductions in bone mineral density (BMD) and trabecular microarchitecture. Notably, at the time point examined, ORX was associated with a suppressed bone remodeling state, reflected by reductions in both TRAP-positive osteoclasts and ALP-positive osteoblasts, together with lower serum BALP, CTX-1, and Gla/Glu-OC ratio. Conversely, CGAC normalized this stagnant state and restored physiological remodeling. This was accompanied by reduced marrow fat accumulation through the AMPK signaling axis, which upregulated Runx2 and downregulated PPAR-γ. In vitro results confirmed that CGAC promoted osteoblast differentiation and mineralization while suppressing RANKL-induced osteoclastogenesis. These actions suggest that CGAC may be involved in regulating Wnt/β-catenin signaling. Conclusions: Overall, CGAC is a promising therapeutic candidate for male osteoporosis, offering pharmacological benefits particularly relevant to aging populations.