  We study the impact on the Sun of an exotic energy-loss channel caused by
plasmon decay into fermionic minicharged particles with charge $\epsilon e$ and
mass $m_f$. We compare solar models with this extra emission to
helioseismological and neutrino data, obtaining a bound $\epsilon <2.2\times
10^{-14}\ ({\rm 95\%\, CL})$ for $m_f\lesssim 25 \, \text{eV}$. Our result is
comparable to previous limits from the cooling of globular cluster stars, while
at the same time it is better understood and takes theoretical and
observational errors into account.
