A randomized, double-blind, placebo-controlled trial to determine the effects of topical insulin on wound healing

Although the literature contains evidence demonstrating the beneficial effects of insulin on wound healing, no suitable method for the routine administration of insulin has been reported. A randomized, double-blind, placebo-controlled trial was conducted to determine the safety and efficacy of topical insulin on healing in 45 patients (29 men, mean age for both groups 40.62 years, range 12 to 71 years) with noninfected acute and chronic extremity wounds. Patients were randomly assigned to twice-daily topical application (spray) of 1 cc saline 0.9% for each 10 cm2 of wound with or without 10 units (0.1 cc) of insulin crystal and insulin. The endpoint was complete wound closure. Systemic glucose levels were measured before and 1 hour after treatment application. No patients developed signs or symptoms of hypoglycemia and glucose levels pre- and post-application did not differ significantly. Time to healing did not differ significantly between treatment groups. Healing rates were affected by baseline wound area, patient age, wound type (acute versus chronic), and treatment group. The mean rate of healing rate was 46.09 mm2/day in the treatment and 32.24 mm2/day in the control group (P = 0.029), independent of baseline wound size. In this study, the topical application of insulin was safe and effective. Clinical studies with a larger sample size and that include patients with diabetes mellitus are warranted.