TestoJack Now Foods contains a potent standardized extract of Eurycoma longifolia, commonly known as Tongkat Ali or Long Jack. and no clinical trials have shown that Tongkat Ali extract (LJ100®) supports in man and healthy reproductive function by regulating / increasing levels of endogenous testosterone. Tongkat Ali stimulates testosterone through two different mechanisms: A mechanism works by releasing testosterone binding globluina, UNAP roteína that carries testosterone in the blood and prevents it from entering the muscle cells, which can stimulate growth. The other mechanism is stimulating Leydig cells found in the testes to directly increase testosterone production. Now Foods has completed the formula TestoJack adding Tribulus Terrestris and ZMA. Two well-known and effective ingredients used to stimulate testosterone production.