Rationale: Vitamin D (VitD) effects take place by binding to its receptor (VDR) which is a classical nuclear receptor responsible for genomic effects, but there is also a fraction of the VDR located in the muscle plasma membrane that is responsible for its non-genomic effects. In addition to the established effect of VitD in bone and mineral homeostasis, VitD insufficiency/deficiency is linked to a range of muscle disorders including frailty and muscle loss/dysfunction. Flavonoids decrease insulin resistance and have antioxidant and anti-inflammatory properties by activating Akt signaling pathways. Our study has aimed to evaluate, in VitD deficient conditions, if cocoa flavonoids (CF) are able to mediate the interacction between VitD and skeletal muscle glucose uptake by triggerring the modulation of its genomic and non-genomic signaling pathways. This could be useful in pathological deficient VitD situations, such as diabetes or sarcopenia where muscle function is compromised due to the onset of insulin resistance.