Hordenine is a molecule found in a variety of plants alongside other adrenergic amines such as tyramine or synephrine, and has been linked to having adrenergic effects after intravenous administration. Practically, Hordenine is very underresearched and comparative analysis' between other stimulants cannot be conducted right now.
Technically Hordenine can be used as a stimulant and fat burner due to its associated with tyramine and noradrenaline, but not enough evidence exists currently to support its usage as nutritional supplementation.
Hordenine is on the FDA's Dietary Supplement Ingredient Advisory List as of April, 2019. These are ingredients that do not appear to be lawful ingredients in dietary supplements. The list is subject to change (check the provided link for current status).