Mínguez-Alarcón, L., Chavarro, J. E., Mendiola, J., Roca, M., Tanrikut, C., Vioque, J., ... Torres-Cantero, A. M. (2017, March–April). Fatty acid intake in relation to reproductive hormones and testicular volume among young healthy men [Abstract]. Asian Journal of Andrology, 19(2), 184–190. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/27834316
So what is this Big T, anyway? Derived from cholesterol, testosterone is a steroid hormone—called an androgen—that causes the development and maintenance of masculine characteristics. It's mainly secreted by the testicles in males, although the adrenal cortex and ovaries in females also secrete testosterone—though only about one-tenth the amount as in healthy males.

The amount of testosterone synthesized is regulated by the hypothalamic–pituitary–testicular axis (see figure to the right).[129] When testosterone levels are low, gonadotropin-releasing hormone (GnRH) is released by the hypothalamus, which in turn stimulates the pituitary gland to release FSH and LH. These latter two hormones stimulate the testis to synthesize testosterone. Finally, increasing levels of testosterone through a negative feedback loop act on the hypothalamus and pituitary to inhibit the release of GnRH and FSH/LH, respectively.

A recent study compared total and bioavailable testosterone levels with inflammatory cytokines in men aged 65 and over. There was an inverse correlation with the pro-inflammatory soluble interleukin-6 receptor, but no association with interleukin-6 (IL-6), highly sensitive CRP (hsCRP), tumor necrosis factor-α (TNF-α) or interleukin-1β (IL-1β (Maggio et al 2006). Another trial found that young men with idiopathic hypogonadotrophic hypogonadism had higher levels of proinflammatory factors interleukin-2 (IL-2), interleukin-4 (IL-4), complement C3c and total immunoglobulin in comparison to controls (Yesilova et al 2000). Testosterone treatment in a group of hypogonadal men, mostly with known coronary artery disease, induced anti-inflammatory changes in the cytokine profile of reduced IL-1β and TNF-α and increased IL-10 (Malkin, Pugh, Jones et al 2004).
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 group's 2010 clinical practice guidelines make it clear that "the threshold testosterone level below which symptoms of androgen deficiency and adverse health outcomes occur and testosterone administration improves outcomes in the general population is not known." They also clearly advise against screening men in the general population to avoid "labeling and medicalization of otherwise healthy men for whom testing, treatment, and monitoring would represent a burden with unclear benefit."
The chemical synthesis of testosterone from cholesterol was achieved in August that year by Butenandt and Hanisch.[183] Only a week later, the Ciba group in Zurich, Leopold Ruzicka (1887–1976) and A. Wettstein, published their synthesis of testosterone.[184] These independent partial syntheses of testosterone from a cholesterol base earned both Butenandt and Ruzicka the joint 1939 Nobel Prize in Chemistry.[182][185] Testosterone was identified as 17β-hydroxyandrost-4-en-3-one (C19H28O2), a solid polycyclic alcohol with a hydroxyl group at the 17th carbon atom. This also made it obvious that additional modifications on the synthesized testosterone could be made, i.e., esterification and alkylation.
When females have a higher baseline level of testosterone, they have higher increases in sexual arousal levels but smaller increases in testosterone, indicating a ceiling effect on testosterone levels in females. Sexual thoughts also change the level of testosterone but not level of cortisol in the female body, and hormonal contraceptives may affect the variation in testosterone response to sexual thoughts.[51]
Total levels of testosterone in the body are 264 to 916 ng/dL in men age 19 to 39 years,[165] while mean testosterone levels in adult men have been reported as 630 ng/dL.[166] Levels of testosterone in men decline with age.[165] In women, mean levels of total testosterone have been reported to be 32.6 ng/dL.[167][168] In women with hyperandrogenism, mean levels of total testosterone have been reported to be 62.1 ng/dL.[167][168]
A large number of trials have demonstrated a positive effect of testosterone treatment on bone mineral density (Katznelson et al 1996; Behre et al 1997; Leifke et al 1998; Snyder et al 2000; Zacharin et al 2003; Wang, Cunningham et al 2004; Aminorroaya et al 2005; Benito et al 2005) and bone architecture (Benito et al 2005). These effects are often more impressive in longer trials, which have shown that adequate replacement will lead to near normal bone density but that the full effects may take two years or more (Snyder et al 2000; Wang, Cunningham et al 2004; Aminorroaya et al 2005). Three randomized placebo-controlled trials of testosterone treatment in aging males have been conducted (Snyder et al 1999; Kenny et al 2001; Amory et al 2004). One of these studies concerned men with a mean age of 71 years with two serum testosterone levels less than 12.1nmol/l. After 36 months of intramuscular testosterone treatment or placebo, there were significant increases in vertebral and hip bone mineral density. In this study, there was also a significant decrease in the bone resorption marker urinary deoxypyridinoline with testosterone treatment (Amory et al 2004). The second study contained men with low bioavailable testosterone levels and an average age of 76 years. Testosterone treatment in the form of transdermal patches was given for 1 year. During this trial there was a significant preservation of hip bone mineral density with testosterone treatment but testosterone had no effect on bone mineral density at other sites including the vertebrae. There were no significant alterations in bone turnover markers during testosterone treatment (Kenny et al 2001). The remaining study contained men of average age 73 years. Men were eligible for the study if their serum total testosterone levels were less than 16.5 nmol/L, meaning that the study contained men who would usually be considered eugonadal. The beneficial effects of testosterone on bone density were confined to the men who had lower serum testosterone levels at baseline and were seen only in the vertebrae. There were no significant changes in bone turnover markers. Testosterone in the trial was given via scrotal patches for a 36 month duration (Snyder et al 1999). A recent meta-analysis of the effects on bone density of testosterone treatment in men included data from these studies and two other randomized controlled trials. The findings were that testosterone produces a significant increase of 2.7% in the bone mineral density at the lumber spine but no overall change at the hip (Isidori et al 2005). These results from randomized controlled trials in aging men show much smaller benefits of testosterone treatment on bone density than have been seen in other trials. This could be due to the trials including patients who are not hypogonadal and being too short to allow for the maximal effects of testosterone. The meta-analysis also assessed the data concerning changes of bone formation and resorption markers during testosterone treatment. There was a significant decrease in bone resorption markers but no change in markers of bone formation suggesting that reduction of bone resorption may be the primary mode of action of testosterone in improving bone density (Isidori et al 2005).
Most people associate testosterone with facial hair, gigantic muscles & illegal steroids.  Naturally produced testosterone plays a very important role in male/female metabolic function.  Lowered testosterone is a chronic epidemic that is threatening lives all around the world.  This article will go over 12 ways to boost testosterone levels naturally through healthy lifestyle measures.
These results have been echoed in clinical trials. A meta-analysis of 24 RCTs looked at weight loss caused by diet or bariatric surgery:[22] In the diet studies, the average 9.8% weight loss was linked to a testosterone increase of 2.9 nmol/L (84 ng/dL). In the bariatric-surgery studies, the average 32% weight loss was linked to a testosterone increase of 8.7 nmol/L (251 ng/dL).

Growth of spermatogenic tissue in testicles, male fertility, penis or clitoris enlargement, increased libido and frequency of erection or clitoral engorgement occurs. Growth of jaw, brow, chin, and nose and remodeling of facial bone contours, in conjunction with human growth hormone occurs.[21] Completion of bone maturation and termination of growth. This occurs indirectly via estradiol metabolites and hence more gradually in men than women. Increased muscle strength and mass, shoulders become broader and rib cage expands, deepening of voice, growth of the Adam's apple. Enlargement of sebaceous glands. This might cause acne, subcutaneous fat in face decreases. Pubic hair extends to thighs and up toward umbilicus, development of facial hair (sideburns, beard, moustache), loss of scalp hair (androgenetic alopecia), increase in chest hair, periareolar hair, perianal hair, leg hair, armpit hair.


Magnesium comes with a strict upper cap. Excess magnesium is hard on your kidneys, and can lead to kidney failure. The NIH recommends that men consume 400-420 mg of magnesium daily, but that they should not exceed 350 mg of supplemental magnesium per day. Because while it’s rare for people to chronically overdose on magnesium through diet (you’d have to eat a lot of almonds and spinach, for example), overdose by supplement is far more common.
According to British Medical Journal (BMJ), the European Male Ageing Study has provided the best estimate of the prevalence of low T—defined as a combination of sexual symptoms and measured testosterone level—finding that only 0.1 percent of men in their forties, 0.6 percent in their fifties, 3.2 percent in their sixties, and 5.1 percent of men in their seventies would meet the criteria for the diagnosis.
Any day that you don’t get 20 minutes of direct sunlight on your skin, you want to supplement with 5,000 IUs of vitamin D3. If you get your blood levels tested and you’re extremely low — below 50 IUs — you typically want to do 5,000 IUs twice a day for three months until you get those numbers up. You can do everything in the world, but if your vitamin D levels aren’t right, your testosterone levels will stay low.
And then there’s also the fact that sodium bicarbonate tends to act as a molecular switch for the cyclic adenosine monophosphate (cAMP). And increased cAMP levels – as you might already know – correlate with increased T production since cAMP activates protein kinase A and serves as a secondary messenger between cells and hormones (study, study, study, study, study, study, study, study, study).
If you want to continue exploring the cool topic of eating foods to improve testosterone. I have some tips for you. First, you should read the post about the testosterone boosting recipes to find how you can cook the foods that you have just read about here. Finally, now that you know the best foods to increase testosterone, it is also crucial that you know which foods to avoid to protect your testosterone.
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Starting around the age of 30, men’s testosterone production begins to decline and only continues to go down as you get older. Whether you simply want to build lean muscle or ensure that you always have healthy levels of testosterone, there are a wide range of dietary supplements that can help to increase your testosterone levels. Let’s take a look at some of the most popular ingredients to boost your testosterone. 
Common side effects from testosterone medication include acne, swelling, and breast enlargement in males.[10] Serious side effects may include liver toxicity, heart disease, and behavioral changes.[10] Women and children who are exposed may develop virilization.[10] It is recommended that individuals with prostate cancer not use the medication.[10] It can cause harm if used during pregnancy or breastfeeding.[10]
The mechanism of age related decreases in serum testosterone levels has also been the subject of investigation. Metabolic clearance declines with age but this effect is less pronounced than a reduction in testosterone production, so the overall effect is to reduce serum testosterone levels. Gonadotrophin levels rise during aging (Feldman et al 2002) and testicular secretory responses to recombinant human chorionic gonadotrophin (hCG) are reduced (Mulligan et al 1999, 2001). This implies that the reduced production may be caused by primary testicular failure but in fact these changes are not adequate to fully explain the fall in testosterone levels. There are changes in the lutenising hormone (LH) production which consist of decreased LH pulse frequency and amplitude, (Veldhuis et al 1992; Pincus et al 1997) although pituitary production of LH in response to pharmacological stimulation with exogenous GnRH analogues is preserved (Mulligan et al 1999). It therefore seems likely that there are changes in endogenous production of GnRH which underlie the changes in LH secretion and have a role in the age related decline in testosterone. Thus the decreases in testosterone levels with aging seem to reflect changes at all levels of the hypothalamic-pituitary-testicular axis. With advancing age there is also a reduction in androgen receptor concentration in some target tissues and this may contribute to the clinical syndrome of LOH (Ono et al 1988; Gallon et al 1989).
It is important not to use any DHEA product without the supervision of a professional. Find a qualified health care provider who will monitor your hormone levels and determine if you require supplementation. Rather than using an oral hormone supplementation, I recommend trans-mucosal (vagina or rectum) application. Skin application may not be wise, as it makes it difficult to measure the dosage you receive. This may cause you to end up receiving more than what your body requires.
In females, this test can find the reason you’re missing periods, not having periods, or having a hard time getting pregnant. Doctors can also use it to diagnose polycystic ovary syndrome (PCOS). That’s a hormone problem that can cause irregular periods and make it hard to get pregnant. A testosterone test can also reveal if you might have a tumor in your ovaries that affects how much of the hormone your body produces.
Alpha-5-Reductase Inhibition– This method for test boosting reduces the concentration of Alpha-5-Reductase, which is an enzyme throughout the body which converts active testosterone to DHT. The effect of this inhibition prevents the degradation of testosterone and by doing so, raises testosterone concentrations in the body. This type of A5R inhibition is also the primary method for treating prostate enlargement, which is caused by high levels of DHT.
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.
Up Regulation – Many herbs available in natural test boosters function as testosterone up regulators or promoters. These function by use of specific natural compounds inside the herb, which once inside the body can naturally signal your DNA to express greater testosterone production. There is a variety of herbs that do this, and by signaling different ‘zones’ in your DNA. In addition, some many work better than others for different people due to variation in the genetic code between different people.
Michael T. Murray, ND, is widely regarded as one of the leading authorities on natural medicine. He is the author of many books, including the classic Encyclopedia of Nutritional Supplements. His latest book is What the Drug Companies Won’t Tell You and Your Doctor Doesn’t Know. Visit him online at doctormurray.com.   Article Courtesy of Better Nutrition  
Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than testosterone, so that its androgenic potency is about 5 times that of T.[114] The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects.
Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4–7 months of age.[15][16] The function of this rise in humans is unknown. It has been theorized that brain masculinization is occurring since no significant changes have been identified in other parts of the body.[17] The male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected.[18]
Hooper, D. R., Kraemer, W. J., Saenz, C., Schill, K. E., Focht, B. C., Volek, J. S. … Maresh, C. M. (2017, July). The presence of symptoms of testosterone deficiency in the exercise-hypogonadal male condition and the role of nutrition [Abstract]. European Journal of Applied Physiology, 117(7), 1349–1357. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/28470410

A recent study conducted on trained subjects showed that squats stimulated a greater testosterone response than leg presses.10 Stick with multijoint exercises like squats, bench presses, and deadlifts—the kinds of compound lifts that'll help jack up your testosterone levels. Since machines isolate a muscle you're working (less stabilizer activity), they're not as good a choice compared to free weights.
To find the best testosterone booster, we collected every supplement available on BodyBuilding.com, and cross-checked our list against the top results on best of lists like MensFitness, BroScience, and BodyNutrition. We only looked at pills since some of the ingredients in testosterone boosters have a reputation for tasting bad, and powders just prolong the experience. There are a lot — 133 of them to be precise — and they all claim to boost testosterone levels. Testosterone (for men) is “thought to regulate sex drive (libido), bone mass, fat distribution, muscle mass and strength, and the production of red blood cells and sperm.” If a supplement can increase your natural testosterone levels, the rest should follow. As we mentioned above, it’s not that simple, and at best, you’ll experience only a short-lived boost.
To find the best testosterone booster, we collected every supplement available on BodyBuilding.com, and cross-checked our list against the top results on best of lists like MensFitness, BroScience, and BodyNutrition. We only looked at pills since some of the ingredients in testosterone boosters have a reputation for tasting bad, and powders just prolong the experience. There are a lot — 133 of them to be precise — and they all claim to boost testosterone levels. Testosterone (for men) is “thought to regulate sex drive (libido), bone mass, fat distribution, muscle mass and strength, and the production of red blood cells and sperm.” If a supplement can increase your natural testosterone levels, the rest should follow. As we mentioned above, it’s not that simple, and at best, you’ll experience only a short-lived boost.
Attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer's type,[100][101][102][103] a key argument in life extension medicine for the use of testosterone in anti-aging therapies. Much of the literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone,[104] where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.
In accordance with sperm competition theory, testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.[40] This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction.
TT may help you but it may have adverse (harmful) results. (See discussion of these side effects below.) The Federal Drug Administration (FDA) has said that testosterone drug labels should state that there is a risk for heart disease and stroke for some men using testosterone products. All men should be checked for heart disease and stroke before, and periodically while on, TT. The AUA however, on careful review of evidence-based peer review literature, has stated that there is no strong evidence that TT either increases or decreases the risk of cardiovascular events.
Why bother with such common micronutrients? Because it's not uncommon for athletes to suffer from zinc and magnesium deficiencies, partly due to inadequate replenishing of levels after intense bouts of exercise. Deficiencies in these key minerals can lead to a poor anabolic hormone profile, impaired immune function, and increased cortisol, ultimately leading to decreases in strength and performance.[6]
The maximum hormone concentration in the blood is reported immediately after the workout. And the effect lasts throughout the day. However, it’s important to ensure that your physical activity is moderate. The matter is that too much high-intensity exercise can give an undesirable result. But even if for any reason you can’t attend a gym, it’s not a problem. Just move as much as possible during the day. Even simple walking will be of great benefit.
About a year ago I had trouble falling asleep and staying asleep. I'd toss in bed for close to an hour before I'd fall asleep and wake up only a few hours later to go to the bathroom. So I then started looking for a supplement to help me sleep. I didn't want to take any type of chemical based supplement; I wanted something natural that wouldn't have any side effects.
How do you boost testosterone naturally? Testosterone is a male sex hormone. Low levels can cause changes to the distribution of body fat and muscle strength. Testosterone reduces with age, but people can boost it with lifestyle changes, including diet and exercise. Adequate sleep, nutritional supplements, and stress reduction may also help. Learn more here. Read now
In accordance with sperm competition theory, testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.[40] This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction.
A recent study compared total and bioavailable testosterone levels with inflammatory cytokines in men aged 65 and over. There was an inverse correlation with the pro-inflammatory soluble interleukin-6 receptor, but no association with interleukin-6 (IL-6), highly sensitive CRP (hsCRP), tumor necrosis factor-α (TNF-α) or interleukin-1β (IL-1β (Maggio et al 2006). Another trial found that young men with idiopathic hypogonadotrophic hypogonadism had higher levels of proinflammatory factors interleukin-2 (IL-2), interleukin-4 (IL-4), complement C3c and total immunoglobulin in comparison to controls (Yesilova et al 2000). Testosterone treatment in a group of hypogonadal men, mostly with known coronary artery disease, induced anti-inflammatory changes in the cytokine profile of reduced IL-1β and TNF-α and increased IL-10 (Malkin, Pugh, Jones et al 2004).
While it would be nice to buy a testosterone pill from the local supplement store and have your testosterone levels go up, such a magic pill does not exist. As you can see from the above rundown, while a few supplements may be somewhat effective if your T levels are already low, none will significantly raise your testosterone above a baseline level. Thus, the basics of keeping your T levels high remain pretty simple:
A sedentary lifestyle is another scourge for modern civilization. And this is a serious danger for men. After all, if physical activity is minimal, the testosterone levels will decrease steadily. And in this situation, strength training exercises are a proven method for raising testosterone. Thus, sports exercises always helped raise the levels of male sex hormone. As a result, the testosterone levels elevate after every workout.

A deep rooted passion, writing for me is as much a pleasure as it is business! From remedies to politics, I love breathing in life into the most mundane of topics! When I am not writing, you will often find me either curled up with a book and a bag of fries, or playing with my son of five years and his many transformers and cars! Wanna watch a movie? Ask me for an unbiased review first! If you ask me what I love most, my answer will be quick: Travel, Food, Movies, Music, Writing, Books, and My Son!
There have been case reports of development of prostate cancer in patients during treatment with testosterone, including one case series of twenty patients (Gaylis et al 2005). It is not known whether this reflects an increase in incidence, as prostate cancer is very common and because the monitoring for cancer in patients treated with testosterone is greater. Randomized controlled trials of testosterone treatment have found a low incidence of prostate cancer and they do not provide evidence of a link between testosterone treatment and the development of prostate cancer (Rhoden and Morgentaler 2004). More large scale clinical trials of longer durations of testosterone replacement are required to confirm that testosterone treatment does not cause prostate cancer. Overall, it is not known whether testosterone treatment of aging males with hypogonadism increases the risk of prostate cancer, but monitoring for the condition is clearly vital. This should take the form of PSA blood test and rectal examination every three months for the first year of treatment and yearly thereafter (Nieschlag et al 2005). Age adjusted PSA reference ranges should be used to identify men who require further assessment. The concept of PSA velocity is also important and refers to the rate of increase in PSA per year. Patients with abnormal rectal examination suggestive of prostate cancer, PSA above the age specific reference range or a PSA velocity greater than 0.75 ng/ml/yr should be referred to a urologist for consideration of prostate biopsy.
From the age of 25–30, a man’s testosterone levels naturally start to decline. This is a problem because strong research shows a link between low testosterone and obesity, increased disease risk and premature death. Healthy testosterone levels are also important for women, along with other key hormones such as estrogen and progesterone. Therefore, everyone should take the necessary lifestyle steps to optimize testosterone levels. You will improve your health and body at the same time.
The testicles produce an enzyme called 11ßHSD-1 which protects your testosterone molecules from the effects cortisol.  During times of prolonged stress and chronically elevated cortisol, there simply is too much cortisol for 11ßHSD-1 to handle.  This results in testosterone molecules being destroyed inside the gonads before they even enter the bloodstream (8, 9).
Androgens may modulate the physiology of vaginal tissue and contribute to female genital sexual arousal.[48] Women's level of testosterone is higher when measured pre-intercourse vs pre-cuddling, as well as post-intercourse vs post-cuddling.[49] There is a time lag effect when testosterone is administered, on genital arousal in women. In addition, a continuous increase in vaginal sexual arousal may result in higher genital sensations and sexual appetitive behaviors.[50]
There's the rub, so to speak. Recalling the cautionary lessons learned about sex steroid hormone therapy in postmenopausal women from theWomen's Health Initiative, Dr. Brad Anawalt wrote in the Journal of Clinical Endocrinology and Metabolism, "We are threatened with a reprise of promiscuous prescription of sex steroid hormone therapy in aging men, obese men, diabetic men, and other groups of men with a high prevalence of low serum androgen levels. We are threatened with a mad 'T' party."
Currently available testosterone preparations in common use include intramuscular injections, subcutaneous pellets, buccal tablets, transdermal gels and patches (see Table 2). Oral testosterone is not widely used. Unmodified testosterone taken orally is largely subject to first-pass metabolism by the liver. Oral doses 100 fold greater than physiological testosterone production can be given to achieve adequate serum levels. Methyl testosterone esters have been associated with hepatotoxicity. There has been some use of testosterone undecanoate, which is an esterified derivative of testosterone that is absorbed via the lymphatic system and bypasses the liver. Unfortunately, it produces unpredictable testosterone levels and increases testosterone levels for only a short period after each oral dose (Schurmeyer et al 1983).
Testosterone [Figure 1] is the main male sex hormone. It is responsible for male sexuality and is the main hormone-producing the features associated with masculinity such as substantial muscle mass, facial hair, libido, and sperm production.[1] Besides, the hormone has other vital functions as the basic chemical composition of testosterone is steroidal; and steroids are known to have significant physiological, as well as psychological, effects in male individuals, especially adults.[1] Testosterone production is reduced gradually in men starting from the age of 30.[2] Hence, testosterone blood concentrations slowly diminish as age progresses. As a result, men may experience a number of physiological and psychological events, such as a lack of sex-drive, erectile dysfunction, acute depression, fatigue, low energy levels, and insomnia.[3]

In a recent study of male workers, men with low testosterone levels had an increased chance of severe erectile dysfunction (Kratzik et al 2005), although such a link had not been found previously (Rhoden et al 2002). Certainly erectile dysfunction is considered part of the clinical syndrome of hypogonadism, and questions regarding erectile dysfunction form part of the clinical assessment of patients with hypogonadism (Morley et al 2000; Moore et al 2004).

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.
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