Insulin aspart, an analogue of human insulin, which is approved for use in people with diabetes, is more rapidly absorbed and achieves higher plasma concentrations than human soluble insulin following subcutaneous injection. Hence, it has a faster and more effective glucose-lowering action, with superior control of postprandial hyperglycaemia compared with human soluble insulin. Its shorter duration of action makes interprandial and nocturnal hypoglycaemia less of a problem than with human soluble insulin. Insulin aspart is approved for use in continuous subcutaneous infusion and offers a valuable treatment option during pregnancy.