Recombinant insulin lispro has a more rapid onset of action and shorter duration than human insulin. The clinical file on insulin lispro is bulky: comparative trials versus human insulin have involved more than 2,000 patients, most of whom were treated for 6 months to 1 year. These trials show that there is no difference in diabetes control according to the type of insulin used, in either type I or type II diabetes. Some cases of resistance to human insulin have been successfully treated with insulin lispro. According to a meta-analysis of trials comparing insulin lispro with human insulin, insulin lispro does not alter the risk of hypoglycaemia. In practice, insulin lispro can be administered just before meals, which is an advantage over human insulin, that has to be administered 30 to 45 minutes before meals. Both types of insulin must be kept in a refrigerator.