Few studies have tested the efficacy of commercially available cosmetic products for preventing striae gravidarum . Therefore, the objective of this study was to evaluate efficacy on prevention of striae gravidarum using a specific anti‐stretch mark cream containing hydroxyprolisilane‐C, rosehip oil, Centella asiatica triterpenes and vitamin E. A randomized, double‐blind, placebo‐controlled trial was conducted between November 2009 and April 2011. Pregnant women were included and classified as treated group (emollient and moisturizer containing hydroxyprolisilane C, rosehip oil, Centella asiatica triterpenes and vitamin E) and control group (cream without the active ingredients). Overall incidence of stretch marks during pregnancy was 33.3% for the control group and 37.6% for the treated group (n.s.). Severity of previous stretch marks significantly increased in the control group during the study (17.8%, P = 0.001), but not in the treated group (6.3%, ns). In women who developed new stretch marks during the study, there was a significantly greater ‘difference in severity’ (between baseline and maximum severity) in control group vs. treated group (0.47 [0.57] vs. 0.14 [0.60], P = 0.031). In women without previous striae, incidence of these marks was significantly lower for the treated group patients compared with control group (5.6% vs. 35%, P = 0.031, OR : 9.2 [95% CI : 1.0–83.3]). The use of the anti‐stretch mark product is proved to be effective in reducing severity of the striae during pregnancy, prevents the appearance of new striae and halts progression of those already present. In women who had no striae at baseline, use of the anti‐stretch mark cream was more effective than placebo in preventing new stretch marks.