  We study baryons in an AdS/CFT model of QCD by Sakai and Sugimoto, realized
as small instantons with fundamental string hairs. We introduce an effective
field theory of the baryons in the five-dimensional setting, and show that the
instanton interpretation implies a particular magnetic coupling. Dimensional
reduction to four dimensions reproduces the usual chiral effective action, and
in particular we estimate the axial coupling $g_A$ between baryons and pions
and the magnetic dipole moments, both of which are proportional to $N_c$. We
extrapolate to finite $N_c$ and discuss subleading corrections.
