Supplementation with a Salmon Bone Complex (CalGo®) Preserves Femoral Neck BMD and Attenuates Lumbar Spine Loss: A 24-Month Randomized, Placebo-Controlled Trial

Background/Objectives: Osteopenia is common in postmenopausal women and predisposes to osteoporosis and fracture, representing a population at risk of bone loss but without indication for pharmacologic therapy. Conventional calcium salts offer modest, often transient gains in bone mineral density (BMD). We evaluated whether CalGo®, a salmon bone complex containing microcrystalline hydroxyapatite within a collagen-rich matrix, preserves BMD versus placebo in post-menopausal women with osteopenia. Methods: In a 24-month, randomized, double-blind, placebo-controlled trial, 80 women (50–80 years) with dual-energy X-ray absorptiometry (DXA)-confirmed femoral-neck osteopenia were assigned to CalGo® (2 g/day) or placebo. The prespecified primary endpoint was 24-month change in femoral-neck BMD (g/cm2) analyzed by linear regression (unadjusted and baseline-adjusted). Secondary endpoints included lumbar spine and distal radius BMD, serum P1NP and β-CTX-I, health-related quality of life, and safety. Results: The primary analysis included participants with 24-month DXA (CalGo® n = 29; placebo n = 30). Femoral-neck BMD was maintained with CalGo® (+0.003 g/cm2; +0.4%) but declined with placebo (−0.017 g/cm2; −2.4%), yielding a significant baseline-adjusted between-group difference of +0.019 g/cm2 (95% confidence interval (CI) 0.001–0.038; p = 0.044). Lumbar-spine loss was attenuated with CalGo® (−0.005 g/cm2; −0.3%) versus placebo (−0.028 g/cm2; −3.4%); the adjusted difference favored CalGo® (+0.026 g/cm2; p = 0.058). In exploratory responder analysis, ≥1% lumbar-spine gain was more likely with CalGo® (32.5% vs. 11.4%; OR 3.61; p = 0.043). No treatment effects were observed at the distal radius, in P1NP or β-CTX-I, or in EQ-5D-3L/EQ-VAS. CalGo® was well tolerated with no hepatic or renal safety signals. Conclusions: CalGo® maintained femoral-neck bone mineral density and reduced lumbar-spine loss over 24 months in osteopenic women, with good tolerability. These findings support its potential role as a nutritional approach for maintaining bone health.