Very cool question! Yes, toothpaste does actually have an effect on pimples. But you have to actually use the PASTE (not gels). Most of these contain alcohol and menthol, which dries out the pimple and also kills off the bacteria. The paste also acts much like a clay mask, so as it dries, it absorbs the excess oil and impurities from the pimple. Be very careful not to leave it on too long or overnight as prolonged use can cause extreme sensitivity and that will then just lead to hyperpigmentation. So put it on for an hour MAX.