In this paper, we study the conjecture of Gardner and Zvavitch from [21], which suggests that the standard Gaussian measure γ enjoys 1 n -concavity with respect to the Minkowski addition of symmetric convex sets. We prove this fact up to a factor of 2: that is, we show that for symmetric convex K and L, and λ ∈ [0, 1],More generally, this inequality holds for convex sets containing the origin. Further, we show that under suitable dimension-free uniform bounds on the Hessian of the potential, the log-concavity of even measures can be strengthened to p-concavity, with p > 0, with respect to the addition of symmetric convex sets.