  Based on MAGIC observations from June and July 2007, we have obtained an
integral upper limit to the VHE energy emission of the globular cluster M13 of
$F(E>200 \textrm{GeV})<5.1\times10^{-12} \textrm{cm}^{-2} \textrm{s}^{-1}$, and
differential upper limits for $E>140 \textrm{GeV}$. Those limits allow us to
constrain the population of millisecond pulsars within M13 and to test models
for acceleration of leptons inside their magnetospheres and surrounding. We
conclude that in M13 either millisecond pulsars are fewer than expected or they
accelerate leptons less efficiently than predicted.
