  We propose a method to determine the trilinear Higgs self coupling that is
alternative to the direct measurement of Higgs pair production total cross
sections and differential distributions. The method relies on the effects that
electroweak loops featuring an anomalous trilinear coupling would imprint on
single Higgs production at the LHC. We first calculate these contributions to
all the phenomenologically relevant Higgs production ($gg{\rm F}$, VBF, $WH$,
$ZH$, $t\bar tH$) and decay ($\gamma \gamma$, $WW^{*}/ZZ^{*}\to 4f$, $b\bar b$,
$\tau \tau$) modes at the LHC and then estimate the sensitivity to the
trilinear coupling via a one-parameter fit to the single Higgs measurements at
the LHC 8 TeV. We find that the bounds on the self coupling are already
competitive with those from Higgs pair production and will be further improved
in the current and next LHC runs.
