Marin Morrell leads Scott to believe that one cannot rise to this status if they ever take a life in The Girl Who Knew Too Much, but as Morrell had been fearing for her life at the time there may be reason to doubt the accuracy of this information.
A True Alpha's status and power cannot be taken, stolen were they to be slain like a regular alpha except for a beta of their own making.
In Season 3, Scott McCall's eyes, during situations of high duress but immense determination, briefly turn alpha red. In Currents, Dr. Deaton confirms Scott has the potential to be a True Alpha. In Lunar Ellipse, Scott rises the alpha rank by determinedly pushing through a mountain ash barrier, successfully breaking it, fully awakening his True Alpha status.