Tribulus: multiple trials show no testosterone effect. Horny Goat Weed: icariin is a weak PDE5 inhibitor in vitro; human data is thin. Fenugreek: mixed libido data. Tongkat Ali: some promising trials but quality varies wildly.
Maxorin focuses on ingredients with mechanistic clarity: nitric oxide substrate, NO protection, mitochondrial energy and adaptogens with randomized data.