TestoFuel is an all-natural nutritional supplement by Roar Ambition that claims to use scientifically proven and all natural ingredients to increase testosterone production. We’ll get to the details of the TestoFuel ingredients shortly, but I can give away at this stage, that my dietician has confirmed that everything in this product is indeed natural. Now, testosterone gets a bad name as it’s always associated with alpha males, aggressive behavior, and illegal doping scandals. But the truth couldn"t be further from the truth, at least when we’re talking about natural ranges.