Is chocolate a stimulant?

Yes

Chocolate does indeed have a stimulating effect, thanks to the theobromine, phenylethylamine and the serotonin. As a result, chocolate alleviates depression and can diminish the effects of stress. Chocolate is a stimulant because it is able to cause the secretion of endorphins in the glands, a substance that has an uplifting effect. Endorphins are released by the brain and are similar to morphine in that they have a soothing effect.