Cocoa butter is the best. Thats what I've always used, and mine are barely visable (they'll be thinner and appear whitish).. however.. escaping stretchmarks is near to impossible. We get them no matter what.
yes, cocoa butter or coconut oil seem to work quite well. But all treatments take a lot of time. Stretch marks fade eventually. and virtually everyone gets them at some point.
Apparently it is the vitamin E in cocoa butter that is the effective ingredient. Also the act of massaging in the butter / oil helps, as it helps the elasticity of the skin..