Recombinant DNA technology allows the production of insulin analogues with faster absorption rates from subcutaneous tissue as compared to conventional human regular insulin. We report the time-action profiles of 12 U subcutaneously injected insulin analogues (B9Asp + B27Glu or B10Asp) as evaluated against human regular insulin by means of the euglycaemic clamp technique (blood glucose 5.0 mmol/l) in healthy men. After injection of 12 U of either insulin preparation identical values were found for maximal insulin action (maximal glucose infusion rate, time to peak action), total amount of glucose infused as well as area under the curve of glucose infusion rate. Half-maximal glucose infusion rate was reached significantly earlier after injection of modified insulins (mean +/- SD 38 +/- 7 and 43 +/- 5 min) as compared to regular insulin (56 +/- 14 min, p less than 0.01). Forty-five min after injection of both insulin analogues glucose infusion rate had increased by 7.4 +/- 1.8 or 6.1 +/- 1.8 mg.kg-1.min-1, reflecting 83 +/- 27 or 67 +/- 15% of maximal regular insulin action. In conclusion, the two tested insulin analogues showed similar action profiles, but a significantly faster onset of action as compared to regular insulin.