Red Xanax Bars | Red Devil Xanax Pills | 8 followers on LinkedIn. Red Xanax bars contain 2 and 3mg of the drug’s active ingredient. | Have you ever wondered what the difference is between a red xanax bar and a normal one?nnYou may have heard that Red Xanax bars are more potent than regular Xanax, but it's not just the color. These little pills contain 2, 3, or 5 milligrams of the drug's active ingredient.