Assume that $A$ is a $C^{*}$ algebra with self adjoint elements $A_{sa}$. Assume that for all $a,b\in A$ we have $$ab\in A_{sa} \iff ba \in A_{sa}$$ >Is $A$ necessarily a commutative algebra? This question is in line of [this post](https://math.stackexchange.com/questions/1687407/is-this-a-characterization-of-commutative-c-algebras)