Procyanidins are a class of polyphenolic compounds commonly found in foods such as apples, grapes, cocoa, and various berries. Their use in supporting or treating osteoporosis has some basis in scientific research, though the evidence is still preliminary and not yet robust. Several in vitro and animal studies have suggested that procyanidins may exert beneficial effects on bone health. These effects are proposed to occur through the stimulation of osteoblast (bone-forming cell) activity, inhibition of osteoclast (bone-resorbing cell) differentiation, and modulation of signaling pathways involved in bone remodeling, such as the RANKL/OPG pathway. Additionally, procyanidins possess antioxidant and anti-inflammatory properties, which may help reduce oxidative stress and inflammation—factors that contribute to bone loss in osteoporosis.

However, clinical evidence in humans is limited. Most studies to date are preclinical, and while results are promising, there is a lack of large-scale, well-designed human trials directly demonstrating efficacy for osteoporosis prevention or treatment. As a result, while there is scientific rationale and some supportive evidence from laboratory and animal research, the overall evidence base remains weak (rated 2/5). Further clinical research is necessary to confirm whether procyanidins can be effectively used in the management of osteoporosis in humans.