  The abundances of light clusters within a formalism that considers in-medium
effects are calculated using several relativistic mean-field models, with both
density-dependent and density-independent couplings. Clusters are introduced as
new quasiparticles, with a modified coupling to the scalar meson field. A
comparison with experimental data from heavy ion collisions allows settling the
model dependence of the results and the determination of the couplings of the
light clusters to the meson fields. We find that extra experimental constraints
at higher density are needed to convincingly pin down the density associated to
the melting of clusters in the dense nuclear medium. The role of neutron rich
clusters, such as $^6$He, in asymmetric matter is discussed.
