PRECLINICAL RESEARCH REPORT • SUNGKYUNKWAN UNIVERSITY, REPUBLIC OF KOREA • 2025
Sungkyunkwan University, one of South Korea’s oldest and most prestigious institutions, conducted rigorous preclinical research on Sigma Anti-Bonding Calcium Carbonate (SAC®) and found it protects bone architecture, reduces active bone resorption, and suppresses the molecular machinery of bone destruction.
About the Research Institution
Sungkyunkwan University (SKKU) was established in 1398 during the Joseon Dynasty, making it one of the oldest universities in Asia and among the most prestigious research institutions in the world.
Department of Integrative Biotechnology • Suwon Campus, Republic of Korea
Research funded by the National Research Foundation of Korea (NRF), Ministry of Education
The Silent Crisis Inside Your Bones: A Global Health Issue That Needs Answers
Postmenopausal osteoporosis affects hundreds of millions of women globally. When estrogen levels drop during menopause, the body’s bone-remodeling system falls out of balance: bone-destroying cells (osteoclasts) begin outpacing bone-building cells (osteoblasts). The result is a progressive, silent architectural collapse within bone tissue.
Standard calcium supplementation has long been considered foundational to bone health. But the SKKU research team asked a harder question: does the form of calcium, how it ionizes, how it signals, how cells respond to it, actually change outcomes at the molecular level?
To answer this, they studied Sigma Anti-Bonding Calcium Carbonate (SACx®), a formulation engineered to enhance the release of freely ionized calcium (Ca²⁺) in aqueous environments. SAC® was tested in the most rigorous available preclinical framework: an ovariectomized mouse model combined with direct cellular mechanistic analysis. The researchers didn’t just measure bone density. They looked inside the bone, at its microscopic scaffold, and what they found changes the conversation about what a calcium supplement should actually do.
Bone strength depends not only on mineral quantity but also on bone quality, which encompasses microarchitecture, matrix composition, mineralization heterogeneity, and structural connectivity.
— Seeman & Delmas, New England Journal of Medicine, 2006
What Is SAC® (Sigma Anti-Bonding Calcium Carbonate)?
SAC® is not your standard calcium. It is a proprietary formulation engineered at the molecular level to enhance ionization and solubility in aqueous (watery) environments. The name refers to its structural design: by leveraging sigma anti-bonding molecular principles, SAC® weakens the intermolecular ionic interactions that normally hold calcium atoms together in tight crystalline formations.
The practical result? A greater proportion of freely dissociable calcium ions, the biologically active form, available for cellular uptake and signaling. This matters because calcium in the body is not just a building block. It is a signaling molecule that influences how bone cells behave, how they grow, and crucially, how and when they destroy bone.
Calcium exists in multiple states in the body — bound to proteins, complexed with phosphate, or as free ionized Ca²⁺. Only the ionized fraction is biologically active for cellular signaling. Conventional calcium supplements vary considerably in how much ionized calcium they release, which is influenced by gastric acidity, formulation type, and individual absorption capacity. SAC®’s design targets this critical ionization step directly.
— SCIENCE NOTE — WHY IONIC FORM MATTERS
How the Study Was Conducted
The SKKU research team ran a 16-week study. Female C57BL/6 mice underwent bilateral ovariectomy to induce estrogen deficiency. Following a 3-week surgical recovery, SAC® was administered orally at 100 or 200 mg/kg/day for 13 continuous weeks. A sham-operated group served as the healthy control baseline, and an untreated OVX group served as the disease model comparator.
At study completion, the team assessed outcomes across three levels: whole-body tolerability (body and organ weights), structural bone architecture (micro-computed tomography and histology), and blood biomarkers of bone metabolism (CTX, BALP, P1NP, osteocalcin).
In parallel, they conducted in vitro experiments using RAW264.7 cells, a validated macrophage precursor cell line, stimulated with RANKL to induce osteoclast differentiation. This allowed the team to directly observe how SAC interacts with the molecular machinery of bone destruction, gene by gene, protein by protein.
The Results: SAC® Preserves the Bone’s Inner Architecture
SAC®-mediated preservation of trabecular number is likely biomechanically meaningful. The primary lesion of postmenopausal bone loss is network disruption rather than uniform thinning.
— Sungkyunkwan University Research Team
The micro-computed tomography (micro-CT) findings were visually and quantitatively striking. Ovariectomized mice showed severe deterioration of their trabecular bone network, a sparse, disconnected scaffold. But mice given SAC® showed meaningful structural preservation in a dose-dependent manner.
The Molecular Story: SAC® Silences Bone Destroyers
The cellular experiments revealed something even more remarkable: SAC® doesn’t just supply minerals, it appears to directly interfere with the molecular machinery that creates osteoclasts, the cells responsible for bone destruction.
When RANKL binds to its receptor RANK on bone marrow precursor cells, it activates p38 MAPK (a protein kinase), which in turn activates NFATc1 — the “master switch” for osteoclast creation. NFATc1 then turns on genes like TRAP, Cathepsin K, and Atp6v0d2 that give osteoclasts their destructive capacity. SAC® was shown to interrupt this cascade at multiple points: suppressing p38 phosphorylation, reducing NFATc1 protein levels, and decreasing expression of all downstream osteoclastic genes — dose-dependently, and without any toxicity to healthy cells.
— SCIENCE NOTE — THE RANKL PATHWAY EXPLAINED
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| Molecular Target | Role in Bone Loss | SAC Effect |
|---|---|---|
| p38 MAPK (phosphorylated) | Signals osteoclast formation downstream of RANKL | Reduced phosphorylation |
| NFATc1 protein | Master transcription factor, the “on switch” for osteoclasts | Dose-dependent reduction |
| MITF protein | Co-regulator of osteoclast gene expression program | Reduced expression |
| TRAP mRNA | Osteoclast activity marker, marks actively resorbing bone | Suppressed |
| Cathepsin K (Ctsk) mRNA | Protease that physically dissolves bone collagen matrix | Suppressed |
| Atp6v0d2 mRNA | Ion pump enabling acid secretion for mineral dissolution | Suppressed |
What the Research Team Concluded
The SKKU authors concluded that SAC® may mitigate estrogen deficiency–associated trabecular bone deterioration through suppression of osteoclast differentiation and modulation of the p38–NFATc1/MITF signaling axis.
Modulation of calcium ion availability may therefore influence bone remodeling beyond conventional mineral supplementation and represents a potential strategy for managing postmenopausal osteoporosis.
— Oh Y, Yoo BC et al. — Dept. of Integrative Biotechnology, Sungkyunkwan University
These are preclinical findings. Human clinical trials are the next step. But when a 626-year-old institution produces results this consistent across structural imaging, blood biomarkers, and molecular signaling, the foundation for confidence is real.
Why This Research Matters for You Right Now
Conventional Calcium: The Difference That Matters
The distinction between SAC® and ordinary calcium is not marketing language — it is structural chemistry with measurable biological consequences:
When RANKL binds to its receptor RANK on bone marrow precursor cells, it activates p38 MAPK (a protein kinase), which in turn activates NFATc1 — the “master switch” for osteoclast creation. NFATc1 then turns on genes like TRAP, Cathepsin K, and Atp6v0d2 that give osteoclasts their destructive capacity. SAC® was shown to interrupt this cascade at multiple points: suppressing p38 phosphorylation, reducing NFATc1 protein levels, and decreasing expression of all downstream osteoclastic genes — dose-dependently, and without any toxicity to healthy cells.
— SCIENCE NOTE — THE RANKL PATHWAY EXPLAINED
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Frequently Asked Questions
The study was conducted by researchers at Sungkyunkwan University’s Department of Integrative Biotechnology in Suwon, South Korea, one of Asia’s oldest and most respected research universities, founded in 1398. The research was supported by the National Research Foundation of Korea (NRF) through the Ministry of Education, following IACUC-approved protocols.
Preclinical research is the essential scientific foundation that informs what is worth testing in human clinical trials. The ovariectomized mouse model used in this study is the regulatory gold standard for evaluating interventions targeting postmenopausal bone loss. While human clinical trials remain the final confirmation, findings this consistent across both a validated animal model and cellular mechanistic assays represent a very strong evidence foundation.
CTX, C-terminal telopeptide of type I collagen, is the most widely used biomarker of bone resorption in both clinical and research settings. Elevated CTX levels directly reflect increased osteoclast activity and accelerated bone loss. The significant reduction in CTX in SAC-treated mice, alongside preserved bone architecture on micro-CT, provides convergent evidence that SAC genuinely reduces active bone destruction.
No. At both doses tested, 100 and 200 mg/kg daily for 13 weeks, SAC® produced no significant changes in body weight or in the weight of any major organ including the liver, kidney, lung, spleen, brain, stomach, and intestine. In cell viability assays, SAC showed no cytotoxicity at any dose tested.
Disclaimer
This article is based on preclinical research and is intended for educational and informational purposes only. It does not constitute medical advice. The findings described represent results from animal and cell-based studies; human clinical outcomes may differ. Consult a qualified healthcare professional before beginning any supplement regimen. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Scientific References
