Goodbye Stretch Marks. Scientists at the University of Sevilla just patented the use of L-carnitine for the treatment of stretch marks and scars. According to the researchers, is the first time that they establish the scientific basis for developing a cosmetic product to rebuild the broken frame protein of the dermis that causes stretch marks. According to Rosa María Jiménez-Castilian author of the work, stretch marks are a tearing of the dermis, usually caused by rupture of collagen fibers when they dont have sufficient elasticity to withstand a change in volume of the underlying tissues. The structural and elastic fibers are key in maintaining the structure and elasticity of the skin throughout our life, and L-carnitine restructures them