Disclosed is the field of cosmetic products, in particular, a hair dye, of the permanent coloring type, including: a mixture including primary dyes, couplers, at least one alkalizing substance, a buffer substance, an antioxidant substance; and at least one oxidizing agent. The alkalizing substance is contained in an alkaline solution including: tri-N-propylamine; arginine; water; and an alkalizing agent selected from glucamine and bis (3-aminopropyl) dodecylamine, where the pH value of the alkaline solution is ≥9.5.