The bones and the brain are two important tissues in humans where the primary effect of testosterone is by way of aromatization to estradiol. In the bones, estradiol accelerates ossification of cartilage into bone, leading to closure of the epiphyses and conclusion of growth. In the central nervous system, testosterone is aromatized to estradiol. Estradiol rather than testosterone serves as the most important feedback signal to the hypothalamus (especially affecting LH secretion).[115] In many mammals, prenatal or perinatal "masculinization" of the sexually dimorphic areas of the brain by estradiol derived from testosterone programs later male sexual behavior.[116]
The aim of treatment for hypogonadism is to normalize serum testosterone levels and abolish symptoms or pathological states that are due to low testosterone levels. The exact target testosterone level is a matter of debate, but current recommendations advocate levels in the mid-lower normal adult range (Nieschlag et al 2005). Truly physiological testosterone replacement would require replication of the diurnal rhythm of serum testosterone levels, but there is no current evidence that this is beneficial (Nieschlag et al 2005).
Using steroids eventually trains your body to realize that it doesn’t have to produce as much testosterone to reach its equilibrium, so to reach the same highs you’ll need to take more steroids, and when you stop taking them, your body will need to readjust — you’ll be living with low testosterone for a while (and you’ll need to see a doctor if your body doesn’t readjust on its own). Forcing your body to stay above your natural testosterone, even if you’re naturally low, can create this kind of dependency which ultimately decreases the amount of testosterone your body will produce on its own.

The science backs up the soldier’s self discovery, in fact, exposure to radiation (whether it’s from an army radar or the cell phone in your pocket, or the wifi router in your house) has been shown to lower sperm quality, fertility and testosterone. This is true not only for military personnel (88, 89,90) but all males living in a modern world (91).
However, some of these signs and symptoms can be caused by factors other than low testosterone, including medication side effects, thyroid problems, depression and excessive alcohol use. There are also conditions, such as obstructive sleep apnea, that might affect testosterone levels. Once these conditions are identified and treated, testosterone typically will return to a normal level.
That said, a group of researchers at the National University of Malaysia did a systemic literature review of longjack, looking for clinical research that demonstrated a relationship between the shrub and testosterone levels. Of 150 articles, only 11 met their inclusion criteria — involving humans and scientifically rigorous. However, of those 11 studies, seven “revealed remarkable association” between using longjack and improving male sexual health, while the remaining four “failed to demonstrate sufficient effects.” The team concluded that longjack looks “promising” when it comes to raising low testosterone, and that there is convincing evidence that it works.
This being my initial use of product I do find an overall improvement in mind and body "maleness" related to focused goal and strength improvements. Has it turned me into a super stud..no, but at a recent 60th birthday, increased desire has added to performance and that is what I was looking for.I have reinstated diet and exercise that also has made physical and mental health achievements Will finish current bottle, and evaluate overall products worth once completed. Further evaluation pending...
Cognitive abilities differ between males and females and these differences are present from childhood. In broad terms, girls have stronger verbal skills than boys who tend to have stronger skills related to spatial ability (Linn and Petersen 1985). It is thought that the actions of sex hormones have a role in these differences. Reviewing different cognitive strengths of male versus female humans is not within the scope of this article but the idea that cognition could be altered by testosterone deserves attention.
Both testosterone and 5α-DHT are metabolized mainly in the liver.[1][151] Approximately 50% of testosterone is metabolized via conjugation into testosterone glucuronide and to a lesser extent testosterone sulfate by glucuronosyltransferases and sulfotransferases, respectively.[1] An additional 40% of testosterone is metabolized in equal proportions into the 17-ketosteroids androsterone and etiocholanolone via the combined actions of 5α- and 5β-reductases, 3α-hydroxysteroid dehydrogenase, and 17β-HSD, in that order.[1][151][152] Androsterone and etiocholanolone are then glucuronidated and to a lesser extent sulfated similarly to testosterone.[1][151] The conjugates of testosterone and its hepatic metabolites are released from the liver into circulation and excreted in the urine and bile.[1][151][152] Only a small fraction (2%) of testosterone is excreted unchanged in the urine.[151]
The biggest change I made to my diet was increasing my fat and cholesterol intake. There’s a reason why old school strong men would drink raw eggs — studies have suggested that higher fat and cholesterol consumption results in increased levels of total T; men eating low-fat diets typically have decreased testosterone levels. The emphasis on increasing fat and cholesterol consumption meant I got to eat like Ron Swanson for three months — bacon and eggs and steak was pretty much the staple of my diet.

A related issue is the potential use of testosterone as a coronary vasodilator and anti-anginal agent. Testosterone has been shown to act as a vasodilator of coronary arteries at physiological concentrations during angiography (Webb, McNeill et al 1999). Furthermore men given a testosterone injection prior to exercise testing showed improved performance, as assessed by ST changes compared to placebo (Rosano et al 1999; Webb, Adamson et al 1999). Administration of one to three months of testosterone treatment has also been shown to improve symptoms of angina and exercise test performance (Wu and Weng 1993; English et al 2000; Malkin, Pugh, Morris et al 2004). Longer term studies are underway. It is thought that testosterone improves angina due its vasodilatory action, which occurs independently of the androgen receptor, via blockade of L-type calcium channels at the cell membrane of the vascular smooth muscle in an action similar to the dihydropyridine calcium-channel blockers such as nifedipine (Hall et al 2006).

A study published in the Journal of Steroid Biochemistry studied the effects of diet on serum sex hormones in healthy men. Results showed that when men decreased their healthy fat intake, serum concentrations of androstenedione, testosterone and free testosterone also decreased. (8) This indicates you can add low testosterone to the list of low-fat diet risks.


Looking for ingredients that work in the realm of supplements can be like finding a needle in a haystack. Testosterone boosters, like all dietary supplements, are not approved by the Food and Drug Administration prior to marketing. This lack of oversight dates back to the 1994 Dietary Supplement Health and Education Act (DSHEA), which stipulated that purveyors of supplements weren’t required to prove the safety of their products or the veracity of what’s on the labels to the FDA before listing them for sale. Often, there isn’t a lot of scientific backing behind an ingredient, or research has been done solely on animals, not humans.

Testosterone functions within the brain. There are several lines of evidence for this: there are androgen receptors within the brain; testosterone is converted to both dihydrotestosterone (DHT) and estradiol by the actions of 5-α-reductase and aromatase respectively in the brain; steroid hormones promote neuronal cell growth and survival (Azad et al 2003). Testosterone enhances cerebral perfusion in hypogonadal men and that perfusion takes place specifically in Brodman areas 8 and 24, regions of the brain that are concerned with: strategic planning, higher motor action, cognitive behaviors, emotional behavior, generalized emotional reaction, wakefulness and memory (Greenlee 2000; Azad et al 2003). Studies of cognition demonstrate that older men with higher levels of free testosterone index (a surrogate measure of bioavailable testosterone) have better scores in tests of: visual memory, verbal memory, visuospatial functions and visuomotor scanning. Hypogonadal men have lower scores in tests of memory, visuospatial function, with a faster decline in visual memory (Moffat et al 2002). In a very small, short term placebo-controlled study hypogonadal men with Alzheimer’s Disease (AD) treated with testosterone demonstrated a modest improvement in a cognition assessment score in AD (Tan and Pu 2003).
Present in much greater levels in men than women, testosterone initiates the development of the male internal and external reproductive organs during foetal development and is essential for the production of sperm in adult life. This hormone also signals the body to make new blood cells, ensures that muscles and bones stay strong during and after puberty and enhances libido both in men and women. Testosterone is linked to many of the changes seen in boys during puberty (including an increase in height, body and pubic hair growth, enlargement of the penis, testes and prostate gland, and changes in sexual and aggressive behaviour). It also regulates the secretion of luteinising hormone and follicle stimulating hormone. To effect these changes, testosterone is often converted into another androgen called dihydrotestosterone. 
Testosterone belongs to a class of male hormones called androgens, which are sometimes called steroids or anabolic steroids. In men, testosterone is produced mainly in the testes, with a small amount made in the adrenal glands. The brain's hypothalamus and pituitary gland control testosterone production. The hypothalamus instructs the pituitary gland on how much testosterone to produce, and the pituitary gland passes the message on to the testes. These communications happen through chemicals and hormones in the bloodstream.
Testosterone was first used as a clinical drug as early as 1937, but with little understanding of its mechanisms. The hormone is now widely prescribed to men whose bodies naturally produce low levels. But the levels at which testosterone deficiency become medically relevant still aren’t well understood. Normal testosterone production varies widely in men, so it’s difficult to know what levels have medical significance. The hormone’s mechanisms of action are also unclear.
While researchers in Brisbane, Australia, found that while Testofen (“a standardized [fenugreek] extract and mineral formulation”) significantly improved the sexual arousal, orgasm, and the general quality of life of participants, it did not remarkably increase testosterone above normal levels. Participants who took Testofen were more satisfied with their energy, well-being, and muscle strength than those who took the placebo.
"A lot of the symptoms are mirrored by other medical problems," Hedges says. "And for a long time, we were not attributing them to low testosterone, but to diabetes, depression, high blood pressure, and coronary artery disease. But awareness and appreciation of low testosterone has risen. We recognize now that low testosterone may be at the root of problems."
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