Discovered by a team of researchers seeking a natural alternative for the prevention of breast cancer, this plant indole found in cruciferous vegetables reverses the age-related decline of testosterone. It works by dramatically improving the metabolism of estrogen in your body, which promotes testosterone through two mechanisms:

(1) It improves the testosterone-to-estrogen ratio, amplifying the relative action of testosterone, and

(2) Bumping testosterone from binding proteins called SHBGs that interfere with the ability of testosterone to exert its actions; in this way, it "activates" otherwise dormant testosterone.

In addition to its powerful benefits related to testosterone, DIM is also believed to be responsible for most or all of the protective benefits of cruciferous vegetables, such as prevention (and treatment) of disease, strengthening of the immune system, and more.[1-5]

Tongkat Ali is an herb sometimes referred to as a pro-fertility agent and aphrodisiac. Its testosterone-enhancing effects are well established. In one study published in the British Journal of Sports Medicine, increases in lean muscle and fat loss were observed when Tongkat Ali was used as part of an exercise program.[8]

Like magnesium, zinc is a key mineral that many people are deficient in (especially people who work out, given that zinc is excreted through sweat). Studies have shown that supplementing with the precise amount of zinc included in TEST-XL can improve testosterone levels by 20% or more! Numerous studies also show big increases in free, "bioactive" testosterone, such as one published in the Neuro Endocrinology Letters(2006 Feb-Apr;27(1-2):247-52), which also reported a substantial protective ability of zinc to preserve testosterone levels during and after "exhaustive" exercise, which normally causes testosterone to drop.[9]

Critical to optimal testosterone, magnesium is a mineral that most of the general population – and particularly athletes – are deficient in. In addition to raising testosterone levels, studies have shown that it improves heart health, regulates electrolytes, reduces muscle tension and relieves anxiety and depression. Countless scientific studies demonstrate the testosterone-raising effects of magnesium, including one published in the journal Biological Trace Element Research (2011 Apr;140(1):18-23), which noted a 24% increase in free testosterone in just 4 weeks among participants who supplemented with 10 mg of magnesium per kg of body weight.[10]

Vitamin B6 increases testosterone by triggering luteinizing hormone, which directly stimulates natural T production. Additionally, vitamin B6 suppresses estrogen, leading to increases in both free and total testosterone. Vitamin B6 also increases the production and transport of red blood cells in your body, improving the oxygen-carrying capacity of your blood and dramatically improving endurance.

Piperine, a component of black pepper, enhances the absorption of nutrients. One study showed an incredible 20-fold increase in absorption (a 2,000% improvement!).[11] Here's how: It stimulates the secretion of hydrochloric acid in your gut, which breaks down foods at a much higher rate, improving absorption. Also: it improves gastrointestinal flora, and eradicates parasites and candida from your gut, improving the health and effectiveness of your entire digestive tract. A precise amount of piperine is the secret weapon that dramatically improves the absorption of DIM and the remarkable natural ingredients described above, so that you can take full advantage of TEST-XL's powerful formula.