In recent years, Platelet Rich Plasma (PRP) and Adipose-Derived Stem Cells (ADSCs) have been used separately for many clinical applications, especially skin rejuvenation. A combined injection of PRP and ADSCs could therefore be used to treat skin wrinkles. However, there are controversies and reports with conflicting results regarding the efficacy of this treatment. The authors aimed to determine the anti-wrinkle and skin rejuvenation mechanism of combined PRP and ADSCs treatment. The effects of PRP and ADSCs isolated from the same consenting donors were evaluated using in vitro and in vivo models. The in vitro effects of PRP and ADSCs on dermal fibroblast proliferation, collagen production, and inhibition of Matrix Metalloproteinase-1 (MMP-1) production were investigated using a co-culture model. Fibroblasts and ADSCs were cultured within the same dish, but in two separate cavities (using an insert plate), in the presence of the same PRP-supplemented medium. In vivo, the authors evaluated the effects of combined PRP and ADSCs on skin histochemistry, including changes in the dermal layer and collagen production in photo-aged skin (mice). They also determined the survival and differentiation of grafted ADSCs. The results show that combined PRP and ADSCs strongly stimulate in vitro fibroblast proliferation, collagen production, and inhibition of MMP-1 synthesis. Intra-dermal co-injection of PRP and ADSCs was observed to stimulate increased dermal layer thickness and collagen production compared with the untreated group. These results indicate that a combined PRP and ADSC injection can reduce wrinkles more effectively than either PRP or ADSC alone, and provide insight into the clinical use of PRP combined with ADSCs for dermal applications, particularly skin rejuvenation.