A convenient, sterile-filtered cocktail solution (1000X, in DMSO) containing two small molecules useful for enhancing the reprogramming efficiency of human somatic cells to induced pluripotent stem cells (iPSCs). The two small molecule inhibitors are: CHIR99021 (Cat. No. 1677, 3.0 mM) and PD0325901 (Cat. No. 1643, 1.0 mM).