It is suggested that the primary mechanism by which ashwagandha increases testosterone is through lowering cortisol, the 'stress' hormone. It does this by reducing activity in the hypothalamus-pituitary-adrenal (HPA) axis which regulates cortisol . Lower levels of cortisol allow for elevated testosterone. Ashwagandha also upregulates the activity of gonadotropin-releasing hormone which stimulates the Leydig cells in the testes to produce testosterone .
In terms of aiding cognition there are a plethora of studies highlighting this herb's ability to protect against neurodegenerative diseases such as Alzheimer's, Huntingtons and Parkinsons disease. It is proposed that this is achieved through mitigating cell death and inflammation and aiding in endothelial and mitochondrial function . Moreover, many studies suggest that ashwagandha is an aromatase inhibitor. Aromatase is the enzyme needed to transform testosterone to estradiol (an estrogen hormone) so stopping this transformation maintains higher testosterone levels .
Despite shilajit having fewer clinical studies than the other indgredients, the studies that have been done show very promising results for the compound's effect on testosterone and sperm count. Although it is not as heavily researched as many other minerals there is millenia of empirical evidence in arurvedic medicine to suggest its efficacy.
Processed shilajit contains di-benzo-alpha-pyrone which increases spermatogenic activity causing sperm count to increase .
In a study where patients took 500mg of purified Shilajit per day, the two gonadotropic hormones; Leutinizing hormone (LH) and Follicle Stimulating Hormone (FSH) were down regulated and the HPA was supported. Down regulation means that the body is less concerned with reducing the amount of these hormones found in the blood. This increases the serum levels of FSH and LH and as a result testosterone levels are increased .
It has been suggested that zinc may increase the conversion of androstenedione to testosterone via a reduction reaction. It has also been shown that zinc decreases the metabolism of testosterone done in the liver. This means that more testosterone remains in the blood .
It is estimated that 20% of the world is defficient in zinc  ,and low zinc levels are proven to cause leydig cell failure . The Leydig cells, as mentioned above, are where testosterone is produced. Therefore having sufficient zinc levels increases and maintains testosterone production.
Zinc is proposed to also increase testosterone via the following mechanism: zinc binds to G-coupled proteins thereby releasing a messenger chemical called cAMP. This in turn increases production of chorionic gonadotropin hormone (HCG). HCG then induces the production of more testosterone .
Sex hormone binding globin (SHGB) binds with circulating free testosterone to carry it around then body. However, when binded, testosterone is not biologically active, this means that it cannot be used by the body for testosterone's many benefits. Magnesium has been shown to reduce the affinity (strength) of the bonding between testosterone and SHGB therby increasing the levels of bioavailable testosterone that circulate the blood stream .
As with many of the other ingredients in Atlas Testosterone Support, magnesium maintains the capacity of antioxidants and controls oxidative stress. This reduces the inhibiting effect on testosterone production that inflammatory cytokines (cell signalling molecules) have at the pituitary gland and testicles .
One clinical study found a significant increase in bioavailable testosterone levels after just one week of 10mg/day boron supplementation . It is suggested that Boron supplementation increases the conversion of total testosterone to bioavailable testosterone which was indicted in the study by lower levels of blood plasma estradiol (female sex hormone).
Some research has suggested that boron possesses anti-carcinogenic properties. For example boric acid ingestion, found in drinking water could inhibit human prostate cancer , .
It was also observed that after a weeks supplementation of boron, inflammatory biomarker levels (such as hsCRP and IL-6 levels) were drastically reduced (50%) . The importance of this is two-fold: 1) reduction in hsCRP has been shown to correlate with a reduction in cardiac events . 2) Reducing IL-6 levels (an inflammatory biomarker) allows for elevated testosterone levels .
Vitamin D levels are controlled via vitamin D receptors (VDR). It has been proven that a number of VDR's are found in the male reproductive tract, germ cells and Leydig cells: the main sites of testosterone production in men . Studies show that there is a positive association between Vitamin D and testosterone . Although the mechanism has not been found, researchers suggest the location of the VDR's in these important testosterone production areas may be the answer.
Calcium is an essential nutrient for male sex hormone synthesis and vitamin D is a known regulator of calcium. Vitamin D increases the metabolism of calcium in the intestines and as a result more calcium is absorbed by the body. More calcium, more sex hormones. More sex hormones, more testosterone .
Vitamin D and Vitamin K2, like many pairs of vitamins , work synergistically. Vitamin D is required to build Matrix GLA Proteins (MGP).
It has been shown the Vitamin K2 activates MGP when in the blood stream. These MGPs are able to prevent and even reverse calcium plaque from arterial walls, which is a cause of heart disease and attacks .
Calcium is essential for maintaining good bone density and preventing bone fractures. It has been noted that Vitamin K2 supports the absorption of calcium into the bones. This means that the benefits of calcium intake can be enjoyed without the associated heart risk .