This is natural amino acid and can boost testosterone levels. According to research, it increases the production of luteinizing hormone which triggers the production of testosterone from Leydig cells. It also helps in improving sperm quality and quantity. The men who take this have increased testosterone production which allows them to perform better in athletic activity. It helps to increase muscle mass and strength.
The converse is also true; there is an increased incidence of rheumatic/autoimmune disease in men with hypogonadism. Jimenez-Balderas et al (2001) carried out neuroendocrine, genetic and rheumatologic investigations in hypogonadal men. Of the 13 hypogonadal patients, 8 (61%) had rheumatic autoimmune disease (ankylosing spondylitis, systemic lupus erythemetosus, rheumatoid arthritis, dermatomyositis). There is a low frequency of those diseases (0.83%) in the general population.
Decreased testosterone production in men with rheumatoid arthritis is a common finding (Stafford et al 2000), and it is now generally recognized that androgens have the capacity to suppress both the hormonal and cellular immune response and so act as one of the body’s natural anti-inflammatory agents (Cutolo et al 2002). This known anti-inflammatory action of testosterone has led to studying the effect of testosterone therapy in men with rheumatoid disease. Although not all studies have reported positive effects of testosterone treatment (Hall et al 1996), some studies do demonstrate an improvement in both clinical and chemical markers of the immune response (Cutolo et al 1991; Cutolo 2000). This observation would go along with more recent evidence that testosterone or its metabolites protects immunity by preserving the number of regulatory T cells and the activation of CD8+ T cells (Page et al 2006).

Although, most studies on TT have been conducted on animals, the results appear promising. One study that looked at sexually sluggish male albino rats found that having been given extracts of TT, the rats "mount frequency, intromission frequency, and penile erection index" all increased, while "mount latency, intromission latency, and ejaculatory latency" all decreased. Who said romance was dead?
Dr. Ronald Swerdloff, chief of the endocrinology division at the Harbor-UCLA Medical Center and a professor of medicine at UCLA's David Geffen School of Medicine, served on the panel of experts who developed the Endocrine Society's guidelines. He is also the principal investigator for one of the 12 sites of The Testosterone Trial in Older Men, a nationwide study funded mainly by the National Institute on Aging. The study of 800 men over age 65 with low testosterone is looking at whether men using AndroGel for one year, compared to placebo, will show improvements in walking speed, sexual activity, vitality, memory, and anemia. The study will be completed in June 2015.
They also don't make clear how risky exposure to testosterone gel is for others—female partners, children, even pets. The gel is actually notorious for transferring to others. It can cause excess hair to grow on women's faces and arms, deepen their voices, interrupt menstruation, and make them anxious and irritable. In children, exposure to testosterone gels and creams can cause premature puberty and aggression. And in pets, it can cause aggressive behavior and enlargement of the genitalia.
Epidemiological data has associated low testosterone levels with atherogenic lipid parameters, including lower HDL cholesterol (Lichtenstein et al 1987; Haffner et al 1993; Van Pottelbergh et al 2003) and higher total cholesterol (Haffner et al 1993; Van Pottelbergh et al 2003), LDL cholesterol (Haffner et al 1993) and triglyceride levels (Lichtenstein et al 1987; Haffner et al 1993). Furthermore, these relationships are independent of other factors such as age, obesity and glucose levels (Haffner et al 1993; Van Pottelbergh et al 2003). Interventional trails of testosterone replacement have shown that treatment causes a decrease in total cholesterol. A recent meta-analysis of 17 randomized controlled trials confirmed this and found that the magnitude of changes was larger in trials of patients with lower baseline testosterone levels (Isidori et al 2005). The same meta-analysis found no significant overall change in LDL or HDL cholesterol levels but in trials with baseline testosterone levels greater than 10 nmol/l, there was a small reduction in HDL cholesterol with testosterone treatment.
Here’s one proof: in a number of British rivers, 50 percent of male fish were found to produce eggs in their testes. According to EurekAlert,3 EDCs have been entering rivers and other waterways through sewage systems for years, altering the biology of male fish. It was also found that fish species affected by EDCs had 76 percent reduction in their reproductive function.
In general, the normal range in males is about 270 to 1070 ng/dL with an average level of 679 ng/dL. A normal male testosterone level peaks at about age 20, and then it slowly declines. Testosterone levels above or below the normal range are considered by many to be out of balance. Moreover, some researchers suggest that the healthiest men have testosterone levels between 400 - 600 ng/dL.
The definition of the metabolic syndrome continues to be a work in progress. Within the last decade a number of definitions have emerged each with its own set of criteria although there is considerable overlap among them. The most recent definition seems to enjoy considerable consensus. It requires central adiposity (>94 cm waist circumference) plus two of, increased triglycerides, decreased HDL cholesterol, hypertension, insulin resistance as evidenced by impaired glucose tolerance, or frank diabetes (Alberti 2005). Almost immediately on the heels of this consensus, came a number of specific chemical markers which have been proposed to complement the basic definition of the metabolic syndrome (Eckel et al 2005).
Men can experience a range of symptoms if testosterone decreases more than it should. Low testosterone, or low T, is diagnosed when levels fall below 300 nanograms per deciliter (ng/dL). A normal range is typically 300–1000 ng/dL, according to the U.S. Food and Drug Administration. A blood test called a serum testosterone test is used to determine your level of circulating testosterone.
Testosterone makes a contribution to nitric oxide formation. Nitric oxide, released from penile nerves stimulates guanylate cyclase which catalyzes the transformation of guanosine-5-triphosphate into 3′,5′-cyclic, guanosine monophosphate (cyclic GMP). Gyclic GMP causes vasodilatation and hence erection formation (Morelli et al 2005). The breakdown of cyclic GMP to GMP is mediated by the enzyme, phosphodiesterase type-5, the inhibitors of which (eg, sildenafil citrate) enhance erection formation and maintanence (Carson and Lue 2005).
Here’s one proof: in a number of British rivers, 50 percent of male fish were found to produce eggs in their testes. According to EurekAlert,3 EDCs have been entering rivers and other waterways through sewage systems for years, altering the biology of male fish. It was also found that fish species affected by EDCs had 76 percent reduction in their reproductive function.

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.

Every ingredient can be harmful when taken in significant quantities (we go more into that below), so we pored over each booster’s ingredient list to make sure that they weren’t serving up an overdose. In particular, we took a close look at magnesium and zinc, which have enough scientific background behind them to offer hard upper limits on how much you can safely consume.
However, along with bone healthy and density, vitamin D may also ensure proper testosterone production in men. Studies suggest a correlation between low testosterone levels and vitamin D deficiencies. Other research suggests that men supplementing with vitamin D experienced a statistically significant increase in testosterone levels. Studies found that simply spending more time in the summer sun increased the subjects’ vitamin D and testosterone levels.
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).

It doesn’t get more natural than getting a good night’s sleep. Research published in the Journal of the American Medical Association showed that lack of sleep can greatly reduce a healthy young man’s testosterone levels. That effect is clear after only one week of reduced sleep. Testosterone levels were particularly low between 2 and 10 p.m. on sleep-restricted days. Study participants also reported a decreased sense of wellbeing as their blood testosterone levels dropped.

Testosterone levels generally peak during adolescence and early adulthood. As you get older, your testosterone level gradually declines — typically about 1 percent a year after age 30 or 40. It is important to determine in older men if a low testosterone level is simply due to the decline of normal aging or if it is due to a disease (hypogonadism).