NovoMix 30 contains insulin aspart, a rapid-acting insulin that works very quickly and is taken right before meals. Human Mixtard 30 contains soluble human insulin, which acts a bit slower and must be taken about 30 minutes before eating. While Human Mixtard 30 is a highly effective and more affordable alternative, switching requires adjusting your injection timing and potentially your dosage. Please consult your doctor before making this change so they can help you transition safely and keep your blood sugar well-controlled.