[en] The reaction rates for α capture processes on self-conjugate nuclei in the mass range A=20 -40 have been investigated. The rates were calculated using the statistical model code NON-SMOKER taking into account isospin suppression rules. These theoretical predictions are compared with rates derived from the available experimental data about the α capture reactions but taking also into account additional experimental information from different reaction channels populating the α unbound states of the self-conjugate compound nuclei