  In this paper we study the $\eta'$ in $N_f=2+1+1$ lattice QCD simulations at
finite temperature. Results are obtained from the analysis of the gluonic
defined topological charge density correlator after gradient flow. Our results
indicate the growth of the $\eta'$ mass above the pseudocritical temperature,
associated with the chiral symmetry restoration. In the vicinity of the
pseudocritical temperature the results are consistent with a small dip in the
$\eta'$ mass. The magnitude of the dip is compatible with the reduction of the
$\eta'$ mass obtained by experimental analysis and suggests that $\eta'$ mass
comes close to zero temperature non-anomalous contribution.
