4 fingers away from belly button. (approx 2 inches); as area around the belly is highly sensitive. Injection may cause pain in this area.
By the way, paradigms of diabetes have changed now, and we need to go beyond just blood sugar control to avoid complications of diabetes. And Ayurveda is proven to play an excellent role in this issue to help patients in correcting the diabetes pathology beyond bs control by insulin alone. I hv been a practising ayurvedic diabetologist since last 14 years and will be able to help you if you book my on line appointment. Rgds.