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).
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).

Changes in body composition are seen with aging. In general terms, aging males are prone to loss of muscle mass and a gain in fat mass, especially in the form of visceral or central fat. An epidemiological study of community dwelling men aged between 24 and 85 years has confirmed that total and free testosterone levels are inversely correlated with waist circumference and that testosterone levels are specifically related to this measure of central obesity rather than general obesity (Svartberg, von Muhlen, Sundsfjord et al 2004). Prospective studies show that testosterone levels predict future development of central obesity (Khaw and Barrett-Connor 1992; Tsai et al 2000). Reductions in free testosterone also correlate with age related declines in fat free mass (muscle mass) and muscle strength (Baumgartner et al 1999; Roy et al 2002). Studies in hypogonadal men confirm an increase in fat mass and decrease in fat free mass versus comparable eugonadal men (Katznelson et al 1998). Taken together, the epidemiological data suggest that a hypogonadal state promotes loss of muscle mass and a gain in fat mass, particularly visceral fat and therefore mimics the changes of ‘normal’ aging.
In order to discuss the biochemical diagnosis of hypogonadism it is necessary to outline the usual carriage of testosterone in the blood. Total serum testosterone consists of free testosterone (2%–3%), testosterone bound to sex hormone binding globulin (SHBG) (45%) and testosterone bound to other proteins (mainly albumin −50%) (Dunn et al 1981). Testosterone binds only loosely to albumin and so this testosterone as well as free testosterone is available to tissues and is termed bioavailable testosterone. Testosterone bound to SHBG is tightly bound and is biologically inactive. Bioavailable and free testosterone are known to correlate better than total testosterone with clinical sequelae of androgenization such as bone mineral density and muscle strength (Khosla et al 1998; Roy et al 2002). There is diurnal variation in serum testosterone levels with peak levels seen in the morning following sleep, which can be maintained into the seventh decade (Diver et al 2003). Samples should always be taken in the morning before 11 am to allow for standardization.
The use of anabolic steroids (manufactured androgenic hormones) shuts down the release of luteinising hormone and follicle stimulating hormone secretion from the pituitary gland, which in turn decreases the amount of testosterone and sperm produced within the testes. In men, prolonged exposure to anabolic steroids results in infertility, a decreased sex drive, shrinking of the testes and breast development. Liver damage may result from its prolonged attempts to detoxify the anabolic steroids. Behavioural changes (such as increased irritability) may also be observed. Undesirable reactions also occur in women who take anabolic steroids regularly, as a high concentration of testosterone, either natural or manufactured, can cause masculinisation (virilisation) of women.

If in a 46 XY individual testosterone is either not produced in adequate concentrations as in gonadal dysgenesis (MacLaughlin and Donahue 2004), or in the absence of the enzyme 17 alpha-hydroxylase so that testosterone is not produced (Ergun-Longmire et al 2006), or testosterone androgen receptors are absent as in the androgen insensitivity syndrome (Hughes and Deeb 2006), phenotypic females will result.
Studies also show a consistent negative correlation of testosterone with blood pressure (Barrett-Connor and Khaw 1988; Khaw and Barrett-Connor 1988; Svartberg, von Muhlen, Schirmer et al 2004). Data specific to the ageing male population suggests that this relationship is particularly powerful for systolic hypertension (Fogari et al 2005). Interventional trials have not found a significant effect of testosterone replacement on blood pressure (Kapoor et al 2006).
Because of inconclusive or conflicting results of testosterone treatment studies reported in the literature, Rabkin and colleagues (2004) undertook a comparison study among testosterone, the anti-depressant, fluoxetine, and placebo in eugonadal HIV positive men. They found that neither fluoxetine nor testosterone were different from placebo in reducing depression, but that testosterone did have a statistically significant effect in reducing fatigue. It is note-worthy that fatigue was reduced with testosterone treatment even though virtually all the men in the study had testosterone levels within the reference range.
There are studies that show Soy consumption in humans leads to lower sperm count, but unfortunately they did not look at testosterone levels in the study (40). This (41) particular study compared the estrogen production of men drinking soy protein to those drinking whey. After two weeks they found the estradiol levels were equal, however soy drinkers had LOWER Testosterone levels and HIGHER cortisol levels (both bad).
The ingredients in testosterone supplements may be different. Some testosterone supplements contain zinc and magnesium. They increase testosterone levels in men who exercise. Some other testosterone supplements have hormones like DHEA (dehydroepiandrosterone) and pregnenolone. They help with making new testosterone and may help improve the ability to have an erection. But it doesn't seem to be helpful if the problem with erections is caused by diabetes or nerve disorders. Some testosterone booster supplements contain natural ingredients like herbs and botanicals. They may increase testosterone by increasing a hormone produced by the brain, which signals the testicles to produce more testosterone. In addition, others work by releasing bound testosterone, so it is in a form the body can use. Studies do not provide strong evidence that women benefit from taking these supplements. You need to talk to your doctor or pharmacist before starting a testosterone booster supplement. Discuss your medical history and current prescribed medications, over the counter medications, and any supplements that you are taking. Your doctor or pharmacist can tell you if a testosterone booster supplement is right for you. Once you know if a testosterone booster supplement is right for you, Walgreens has a variety of testosterone booster supplements to choose from and they come in different forms like tablets, capsules or gels.
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.

Lean beef, chicken, fish, and eggs are some of your options. Tofu, nuts, and seeds have protein, too. Try to get about 5 to 6 ounces per day, although the ideal amount for you depends on your age, sex, and how active you are. When you don't eat enough of these foods, your body makes more of a substance that binds with testosterone, leaving you with less T available to do its job.
The normal development of the prostate gland is dependent on the action of testosterone via the androgen receptor, and abnormal biosynthesis of the hormone or inactivating mutations of the androgen receptor are associated with a rudimentary prostate gland. Testosterone also requires conversion to dihydrotestosterone in the prostate gland for full activity. In view of this link between testosterone and prostate development, it is important to consider the impact that testosterone replacement may have on the prevalence and morbidity associated with benign prostatic hypertrophy (BPH) and prostate cancer, which are the common conditions related to pathological growth of the prostate gland.
Dr. Anthony's Notes: Creatine is damn effective. Period. It's research proven to benefit testosterone, energy levels, muscle preservation, and your brain function. Although creatine can be found naturally in a good high-protein diet, taking 5g daily is a great idea for most guys – especially those over 35. Remember to take your creatine AWAY from caffeine – the two substances inhibit each other's absorption. Verdict: this is one of the natural testosterone supplements that work. Best Food Sources: wild game (including venison, elk, buffalo, and bison), grass-fed beef, organic chicken, organic turkey, and wild-caught fish. How To Take Creatine Monohydrate: 5g daily away from caffeine.

When you're under a lot of stress, your body releases high levels of the stress hormone cortisol. This hormone actually blocks the effects of testosterone,6 presumably because, from a biological standpoint, testosterone-associated behaviors (mating, competing, aggression) may have lowered your chances of survival in an emergency (hence, the "fight or flight" response is dominant, courtesy of cortisol).


A lifelong habit of learning and engaging in mentally challenging activities seems to keep the brain in shape. Intellectual enrichment and learning stimulate the brain to make more connections, increasing the density of nerve-to-nerve connections. That means the "educated brain" may possess a deeper well of connections and be able to withstand more damage to the brain from a small stroke without causing loss of memory or thinking skills.
A: Depo-Testosterone is a brand name medication that contains testosterone cypionate. Depo-Testosterone is given as an intramuscular injection. The medication is indicated for replacement therapy for men that have conditions associated with symptoms of deficiency in the hormone or absence of testosterone produced in the body. Conditions that can be associated with low testosterone include: delayed puberty, impotence and hormonal imbalances. Testosterone is a sex hormone that is naturally produced in the male testicles. In women, small amounts of testosterone is produced in the ovaries and by the adrenal system. Testosterone is available in various medications for testosterone replacement therapy. Different forms of testosterone (e.g. cypionate, enanthate etc) are contained in different brand name medications. Jen Marsico, RPh
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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.
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.

Binge drinking on the other hand does impact Testosterone levels – especially on a short term basis. Two studies (22 & 23) show that large acute quantities of alcohol consumption in a short period led to decreases in Testosterone levels by a whooping 20-23% after 24hours! Note however this is drinking to extreme excess! Likewise, chronic alcohol abuse is known to reduce testosterone more notably (as seen in alcoholics).
Overall, it seems that both estrogen and testosterone are important for normal bone growth and maintenance. Deficiency or failure of action of the sex hormones is associated with osteoporosis and minimal trauma fractures. Estrogen in males is produced via metabolism of testosterone by aromatase and it is therefore important that androgens used for the treatment of hypogonadism be amenable to the action of aromatase to yield maximal positive effects on bone. There is data showing that testosterone treatment increases bone mineral density in aging males but that these benefits are confined to hypogonadal men. The magnitude of this improvement is greater in the spine than in the hip and further studies are warranted to confirm or refute any differential effects of testosterone at these important sites. Improvements seen in randomized controlled trials to date may underestimate true positive effects due to relatively short duration and/or baseline characteristics of the patients involved. There is no data as yet to confirm that the improvement in bone density with testosterone treatment reduces fractures in men and this is an important area for future study.
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).
A previous meta-analysis has confirmed that treatment of hypogonadal patients with testosterone improves erections compared to placebo (Jain et al 2000). A number of studies have investigated the effect of testosterone levels on erectile dysfunction in normal young men by inducing a hypogonadal state, for example by using a GnRH analogue, and then replacing testosterone at varying doses to produce levels ranging from low-normal to high (Buena et al 1993; Hirshkowitz et al 1997). These studies have shown no significant effects of testosterone on erectile function. These findings contrast with a similar study conducted in healthy men aged 60–75, showing that free testosterone levels achieved with treatment during the study correlate with overall sexual function, including morning erections, spontaneous erections and libido (Gray et al 2005). This suggests that the men in this older age group are particularly likely to suffer sexual symptoms if their testosterone is low. Furthermore, the severity of erectile dysfunction positively correlates with lower testosterone levels in men with type 2 diabetes (Kapoor, Clarke et al 2007).
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 also has vitamin B6. One study called out folate and vitamins B6 and B12 as important nutrients for athletes to achieve optimal health and performance. Vitamin B6 is commonly found in food, like fortified cereals, and as with magnesium, it’s possible to have too much vitamin B6. The NIH recommends an upper daily limit for adults of 100mg per day. Beast Sports comes well under this limit at 10mg per day, but still well above the minimum recommended dose of 1.7mg needed to see benefits.
There is increasing interest in the group of patients who fail to respond to treatment with PDE-5 inhibitors and have low serum testosterone levels. Evidence from placebo-controlled trials in this group of men shows that testosterone treatment added to PDE-5 inhibitors improves erectile function compared to PDE-5 inhibitors alone (Aversa et al 2003; Shabsigh et al 2004).
"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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