A method and a device are described for non-invasive monitoring of blood glucose level of a user. The method includes determining an electrical skin impedance between a first point and a second point of a surface of skin of user using a skin impedance sensor. In an embodiment, electrical skin impedance is indicative of an opacity of surface of skin between first point and second point. The method includes determining a temperature and a hyper spectral signature of skin of user using a temperature sensor and a hyperspectral sensor. The method includes updating a light intensity of a light source based on temperature and hyperspectral signature. In an embodiment, surface of the skin is illuminated based on updated light intensity of light source. The method includes computing a blood glucose level using temperature, hyper spectral signature, and electrical skin impedance. The method includes providing computed blood glucose level to user.