Known by the Latin for a stripe, striae, these are most commonly associated with pregnancy when they are known as striae gravidarum, but there are numerous other conditions when they will occur.
The cause is a distension of the skin that has resulted in lines of rupture of the underlying collagenous structure of the dermis. The lines are always longitudinal over the surface of the sphere, be it belly or biceps, and the skin is thinned at the jagged stria. They are colored blue or red, the color fading gradually over the years to a white scar.
Conditions in which they are found other than pregnancy are associated one way or another with distension of the underlying tissues and are often associated with cortisone. In males, they are found in weight lifters who do get huge muscles but who all too frequently are taking steroids; they occur in the obese, and in persons with congenital abnormalities of collagen formation such as Ehlers Danlos syndrome.
There are many proprietary treatments offered. It is hard to believe torn dermis tissues can be repaired by the local application of creams, no matter what herb they are made from, nor any food or other substance that is ingested. The FDA has approved the use of treatment of striae by laser, so one presumes some supporting evidence of efficacy was submitted.