Abstract
Acne vulgaris is a common dermatologic condition that can lead to scarring, post-inflammatory hyperpigmentation, and psychosocial distress. Microneedling is an established minimally invasive therapy, and topical insulin has been proposed as an adjunct to enhance tissue repair and clinical outcomes. However, the comparative effectiveness of microneedling with or without topical insulin remains unclear. We performed a systematic review and meta-analysis of four trials including 259 patients to evaluate the efficacy and safety of microneedling combined with topical insulin versus microneedling alone. Outcomes assessed included categorical improvement (poor, moderate, good), mean improvement scores, and adverse events. Patients receiving microneedling plus topical insulin experienced a significantly lower rate of poor improvement compared with microneedling alone (risk ratio (RR): 0.35; 95% confidence interval (CI): 0.17-0.76; p = 0.01), while no notable observed differences for good improvement (RR: 2.96; 95% CI: 0.47-18.76; p = 0.25), moderate improvement (RR: 1.16; 95% CI: 0.68-1.98; p = 0.59), or mean improvement scores (standardized mean difference: 0.26; 95% CI: -0.07-0.58; p = 0.12). Adverse events were comparable between groups (RR: 1.53; 95% CI: 0.61-3.83; p = 0.36). Overall, microneedling remains an effective therapy for acne, and adjunctive topical insulin may reduce the risk of poor clinical response without increasing adverse events. These findings suggest potential benefit for selected patients, but larger, well-designed trials are needed to confirm efficacy and optimize treatment protocols.