The current article discusses the peristaltic flow of the Casson fluid model with implications for double diffusivity, radiative flux, variable conductivity and viscosity. This study offers a thorough understanding of the functioning and illnesses of embryological organs, renal systems, respiratory tracts, etc., that may be useful to medical professionals and researchers. The main purpose of the study is to evaluate the consequences of double diffusivity on the peristaltic flow of nanofluid. By implementing the appropriate transformation, the governed differential equations of momentum, temperature, concentration and double diffusivity are worked out numerically. The lowest Reynolds number $Re\to 0$ and highest wavelength $\mathrm{\Omega }\to \mathrm{\infty }$ are used. The ramifications of pertinent parameters on the velocity field, heat, chemical reaction rate and double diffusivity are discussed by plotting the graphs using the bvp4c technique. Our analysis shows that solutal and thermal Grashof numbers enhance the motion of fluid flow over the pumping area of the peristaltic boundary. The activation energy and Lewis number indicate the opposite impact on concentration distribution. Due to variations in thermophoresis and the Brownian parameter, the heating process slows during the pumping section and accelerates during the free pumping section. The graph of double diffusivity initially goes upward by escalating Dufour and Brownian parameters and then moves down over the right sinusoidal geometry.