Stretch mark study, 2010

Trial centre

proDERM institute for applied dermatological research, Hamburg, Germany.


To assess the efficacy of Bi-Oil in improving the appearance of stretch marks.


Subjects: 38 female participants of varying ethnicities. Age of participants: 18 to 65. Stretch mark causes: various (post pregnancy, weight gain or adolescent growth spurt). Stretch mark locations: abdomen, thigh and hips.


Double-blind, randomised and placebo controlled. Subjects had matching stretch marks or a stretch mark large enough to allow a half-half stretch mark application and intra-subject comparison. Product was applied twice daily for 8 weeks, no additional massaging performed on the target area. Application performed under supervision at regular intervals. Assessments conducted at 0, 2, 4 and 8 weeks. Different scar parameters as defined in the Patient and Observer Scar Assessment Scale (POSAS) were evaluated.


Bi-Oil is efficacious in improving the appearance of stretch marks. A statistically significant result after only 2 weeks (day 15), evident in 95% of the subjects. After 8 weeks (day 57) 100% of subjects showed an improvement, with the extent of the improvement more than double that at 2 weeks. A continuous improvement of POSAS over the duration of the study.