Vitamin K, including menadione (a synthetic form), plays a crucial role in bone health through its involvement in the carboxylation of osteocalcin, a protein essential for bone mineralization. There is substantial scientific validation supporting the role of vitamin K (primarily K1 and K2) in the maintenance of bone health and the prevention of osteoporosis. Clinical and epidemiological studies have demonstrated that vitamin K deficiency is associated with lower bone mineral density and increased fracture risk. Supplementation with vitamin K2 (menaquinone) has been shown in randomized controlled trials to improve bone health and reduce fracture rates in some populations, particularly postmenopausal women.

Menadione (vitamin K3) is a synthetic form and is not commonly used as a dietary supplement in humans due to concerns about toxicity; its use is more common in animal nutrition. Most human studies focus on vitamin K1 (phylloquinone) and K2 (menaquinone). Nevertheless, the essential biological role of vitamin K in the activation of bone proteins is well established, and its importance in skeletal health is recognized by scientific authorities such as the Institute of Medicine and the European Food Safety Authority. Thus, while menadione itself is not recommended due to safety concerns, the broader vitamin K group is scientifically validated as crucial for bone health.