Vitamin K has been implicated in skeletal health because vitamin K-dependent proteins are present in bone tissue. While there are multiple forms of vitamin K, most research has focused on phylloquinone, which is found mainly in plant-based foods, and its metabolite menaquinone-4 (MK4). However, there are additional forms of vitamin K that are bacterially produced that appear to influence bone health but have not yet been studied extensively. Herein, we evaluated the effects of menaquinone-9 (MK9), a bacterially produced form of vitamin K, on bone tissue quality and density in young mice. Four-week-old male (