Some of you have probably heard that application of cocoa butter (during pregnancy) reduces the likelihood of developing stretch marks. Well according to a few studies published a few years ago, cocoa butter does not appear to be effective like some believe [1][2].
So how about olive oil? Well, a study published last year does not support the application of olive oil as being effective either [3].
So what oil/butter might work then? Research does support is that massaging with almond oil may reduce the development of stretch marks [4].
SOURCES:
COCOA BUTTER LOTION & STRETCH MARKS (2008)
COCOA BUTTER CREAM & STRETCH MARKS (2010)
OLIVE OIL & STRETCH MARKS (2012)
ALMOND OIL & STRETCH MARKS (2012)