A spacer profile for use as a spacer frame in an insulating window unit includes a profile body made of a synthetic material and having an inner wall, an outer wall and sidewalls, which define a chamber for hygroscopic material. A diffusion barrier layer is made of a first metal material and has a first tensile strength and a first thickness. The diffusion barrier layer is disposed at least on or in the outer wall and at least a portion of the sidewalls. A reinforcement layer is made of a second metallic material and has a second tensile strength and a second thickness. The reinforcement layer is formed in the inner wall or on the side of the inner wall, which is directed towards the chamber. The multiplication product of the second thickness and the second tensile strength is preferably greater than the multiplication product of the first thickness and the first tensile strength.