  We present a compact theorem which reveals the fact that static spatially
regular massive scalar fields with nonminimal coupling to gravity cannot form
spherically symmetric asymptotically flat horizonless matter configurations. In
particular, the no-go theorem rules out the existence of boson stars made of
static scalar fields with generic values of the physical parameter $\xi$ which
quantifies the coupling between the spacetime curvature and the massive bosonic
fields.
