The vascular processes that produce an erection are controlled by the nervous system and certain prescription medications may have the side effect of interfering with necessary nerve signals. Among the possible culprits are a variety of stimulants, sedatives, diuretics, antihistamines, and drugs to treat high blood pressure, cancer, or depression. But never stop a medication unless your doctor tells you to. In addition, alcohol, tobacco, and illegal drugs, such as marijuana, may contribute to the dysfunction.
A number of research groups have tried to further define the relationship of testosterone and body composition by artificial alteration of testosterone levels in eugonadal populations. Induction of a hypogonadal state in healthy men (Mauras et al 1998) or men with prostate cancer (Smith et al 2001) using a gonadotrophin-releasing-hormone (GnRH) analogue was shown to produce increases in fat mass and decreased fat free mass. Another experimental approach in healthy men featured suppression of endogenous testosterone production with a GnRH analogue, followed by treatment with different doses of weekly intramuscular testosterone esters for 20 weeks. Initially the experiments involved men aged 18–35 years (Bhasin et al 2001) but subsequently the study was repeated with a similar protocol in men aged 60–75 years (Bhasin et al 2005). The different doses given were shown to produce a range of serum concentrations from subphysiological to supraphysiological (Bhasin et al 2001). A given testosterone dose produced higher serum concentrations of testosterone in the older age group (Bhasin et al 2005). Subphysiological dosing of testosterone produced a gain in fat mass and loss of fat free mass during the study. There were sequential decreases in fat mass and increases in fat free mass with each increase of testosterone dose. These changes in body composition were seen in physiological and supraphysiological treatment doses. The trend was similar in younger versus older men but the gain of fat mass at the lowest testosterone dose was less prominent in older patients (Bhasin et al 2001; Bhasin et al 2005). With regard to muscle function, the investigators showed dose dependent increases in leg strength and power with testosterone treatment in young and older men but there was no improvement in fatigability (Storer et al 2003; Bhasin et al 2005).
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 is included in the World Health Organization's list of essential medicines, which are the most important medications needed in a basic health system.[172] It is available as a generic medication.[10] The price depends on the form of testosterone used.[173] It can be administered as a cream or transdermal patch that is applied to the skin, by injection into a muscle, as a tablet that is placed in the cheek, or by ingestion.[10]
ED can also occur among younger men. A 2013 study found that one in four men seeking their first treatment for ED were under the age of 40. The researchers found a stronger correlation between smoking and illicit drug use and ED in men under 40 than among older men. That suggests that lifestyle choices may be a main contributing factor for ED in younger men.
Vitamin D and zinc are both essential to testosterone production. A year-long study looked at the vitamin D and testosterone levels of 2299 men. It found that men with vitamin D levels above 30 nmol/L had more testosterone and lower levels of sex hormone-binding globulin (SHBG). SHBG binds to hormones so your cells can’t use them, and if you have too much of it, your testosterone levels drop [8]. Men with vitamin D deficiency had lower testosterone and higher SHBG levels.
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.

Even before the study yields its findings, Dr. Swerdloff said a few important points should be emphasized. "I want to make it clear that this is not a made-up disease," he said. "It is well known in younger men that if you have a failure to produce normal testosterone, there are certain signs and symptoms that create a kind of syndrome. Treatment for low testosterone has been documented to be beneficial."
You’ve probably heard of Viagra, but it’s not the only pill for ED. This class of drugs also includes Cialis, Levitra,  Staxyn, and Stendra. All work by improving blood flow to the penis during arousal. They're generally taken 30-60 minutes before sexual activity and should not be used more than once a day. Cialis can be taken up to 36 hours before sexual activity and also comes in a lower, daily dose. Staxyn dissolves in the mouth. All require an OK from your doctor first for safety.
Chronic stress dumps adrenaline in your system multiple times a day. And that can lead to high blood pressure, heart disease, obesity, and diabetes. Chronic stress is like red-lining your car all day long. When you drive 100 mph all the time, something is going to break down. A high-stress environment can actually change the way your brain sends messages to your body. Dumping too much adrenaline into your bloodstream can affect blood flow and severely limit your ability to achieve and maintain an erection.
Your doctor will ask you questions about your symptoms and health history. They may do tests to determine if your symptoms are caused by an underlying condition. You should expect a physical exam where your doctor will listen to your heart and lungs, check your blood pressure, and examine your testicles and penis. They may also recommend a rectal exam to check your prostate. Additionally, you may need blood or urine tests to rule out other conditions.
In rare cases, the drug Viagra ® can cause blue-green shading to vision that lasts for a short time. In rare cases, the drug Cialis® can cause or increase back pain or aching muscles in the back. In most cases, the side effects are linked to PDE5 inhibitor effects on other tissues in the body, meaning they are working to increase blood flow to your penis and at the same time impacting other vascular tissues in your body. These are not ‘allergic reactions'.
Psychological Causes of ED – Between 10% and 20% of ED cases have a psychological cause. Because arousal starts in the brain, psychological issues can be a significant contributing factor to erectile dysfunction. Mental health conditions like depression or anxiety can negatively impact your libido, making it more difficult for you to become aroused.

The nerves and endothelium of sinusoids and vessels in the penis produce and release transmitters and modulators that control the contractile state of corporal smooth muscles. Although the membrane receptors play an important role, downstream signaling pathways are also important. The RhoA–Rho kinase pathway is involved in the regulation of cavernosal smooth muscle contraction. [12]


Saw palmetto: Uses, dosage, and side effects Saw palmetto is an extract from the berries of a type of palm tree. The berries have traditionally been used to ease urinary and reproductive problems. The extract is now used in herbal remedies to stabilize testosterone. Learn about its use, its effectiveness, the science behind the claims, and any side effects. Read now
When you become aroused, your brain sends chemical messages to the blood vessels in the penis, causing them to dilate or open, allowing blood to flow into the penis. As the pressure builds, the blood becomes trapped in the corpora cavernosa, keeping the penis erect. If blood flow to the penis is insufficient or if it fails to stay inside the penis, it can lead to erectile dysfunction.
All studies demonstrate a strong association with age, even when data are adjusted for the confounding effects of other risk factors. The independent association with aging suggests that vascular changes in the arteries and sinusoids of the corpora cavernosa, similar to those found elsewhere in the body, are contributing factors. Other risk factors associated with aging include depression, sleep apnea, and low HDL levels.
Exercise and lifestyle modifications may improve erectile function. Weight loss may help by decreasing inflammation, increasing testosterone, and improving self-esteem. Patients should be educated to increase activity, reduce weight, and stop smoking, as these efforts can improve or restore erectile function in men without comorbidities. Precise glycemic control in diabetic patients and pharmacologic treatment of hypertension may be important in preventing or reducing sexual dysfunction. [49]

Mood disturbance and dysthymia are part of the clinical syndrome of hypogonadism. Epidemiological studies have found a positive association between testosterone levels and mood, and depressed aging males have lower testosterone levels than controls (Barrett-Connor, Von Muhlen et al 1999). Furthermore, induction of a hypogonadal state during treatment of men for prostate cancer leads to an increase in depression scores (Almeida et al 2004). Trials of testosterone treatment effects on mood have varied in outcome. Data on the effects on men with depression are conflicting (Seidman et al 2001; Pope et al 2003) but there is evidence that testosterone treatment of older hypogonadal men does result in improvements in mood (Wang et al 1996) and that this may occur through changes in regional brain perfusion (Azad et al 2003).


Most studies support a link between adult criminality and testosterone, although the relationship is modest if examined separately for each sex. Nearly all studies of juvenile delinquency and testosterone are not significant. Most studies have also found testosterone to be associated with behaviors or personality traits linked with criminality such as antisocial behavior and alcoholism. Many studies have also been done on the relationship between more general aggressive behavior/feelings and testosterone. About half the studies have found a relationship and about half no relationship.[66]

The PDE5 inhibitors sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis) are prescription drugs which are taken orally.[22]:20–21 Additionally, a cream combining alprostadil with the permeation enhancer DDAIP has been approved in Canada as a first line treatment for erectile dysfunction.[25] Penile injections, on the other hand, can involve one of the following medications: papaverine, phentolamine, and prostaglandin E1.[22]:25
Do erectile dysfunction exercises help? Many people have erectile dysfunction (ED), but it is often possible to reverse this with exercises to strengthen muscles in the area. These include pelvic floor exercises. ED can often be due to lifestyle factors including obesity and low physical activity levels. Learn more about exercises for ED here. Read now

Erectile dysfunction, also known as ED or impotence, is the inability to attain or maintain an erection of the penis adequate for the sexual satisfaction of both partners. It can be devastating to the self-esteem of a man and of his partner. As many as 30 million American men are afflicted on a continuing basis, and transient episodes affect nearly all adult males. But nearly all men who seek treatment find some measure of relief.
The FDA recommends that men follow general precautions before taking a medication for ED. Men who are taking medications that contain nitrates, such as nitroglycerin, should NOT use these medications. Taking nitrates with one of these medications can lower blood pressure too much. In addition, men who take tadalafil or vardenfil should use alpha blockers with care and only as instructed by their physician, as they could result in hypotension (abnormally low blood pressure). Experts recommend that men have a complete medical history and physical examination to determine the cause of ED. Men should tell their doctor about all the medications they are taking, including over-the-counter medications.
Several pathways have been described to explain how information travels from the hypothalamus to the sacral autonomic centers. One pathway travels from the dorsomedial hypothalamus through the dorsal and central gray matter, descends to the locus ceruleus, and projects ventrally in the mesencephalic reticular formation. Input from the brain is conveyed through the dorsal spinal columns to the thoracolumbar and sacral autonomic nuclei.
If PDE5 drugs don't work or cannot be used because of potential side effects, your doctor can recommend other therapies. The drug alprostadil (Caverject, Edex, Muse) allows blood to flow more freely in the penis, leading to an erection. The drug can be injected with a tiny needle into your penis. Or, a small pellet (suppository) can be inserted into the opening of the penis. Suppositories and injections are effective in the majority of men.
Alteration of NO levels is the focus of several approaches to the treatment of ED. Inhibitors of phosphodiesterase, which primarily hydrolyze cGMP type 5, provided the basis for the development of the PDE5 inhibitors. Chen et al administered oral L-arginine and reported subjective improvement in 50 men with ED. [14] These supplements are readily available commercially. Reported adverse effects include nausea, diarrhea, headache, flushing, numbness, and hypotension.

Do erectile dysfunction exercises help? Many people have erectile dysfunction (ED), but it is often possible to reverse this with exercises to strengthen muscles in the area. These include pelvic floor exercises. ED can often be due to lifestyle factors including obesity and low physical activity levels. Learn more about exercises for ED here. Read now
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).
Cross-sectional studies have found a positive association between serum testosterone and some measures of cognitive ability in men (Barrett-Connor, Goodman-Gruen et al 1999; Yaffe et al 2002). Longitudinal studies have found that free testosterone levels correlate positively with future cognitive abilities and reduced rate of cognitive decline (Moffat et al 2002) and that, compared with controls, testosterone levels are reduced in men with Alzheimer’s disease at least 10 years prior to diagnosis (Moffat et al 2004). Studies of the effects of induced androgen deficiency in patients with prostate cancer have shown that profoundly lowering testosterone leads to worsening cognitive functions (Almeida et al 2004; Salminen et al 2004) and increased levels of serum amyloid (Gandy et al 2001; Almeida et al 2004), which is central to the pathogenesis of Alzheimer’s disease (Parihar and Hemnani 2004). Furthermore, testosterone reduces amyloid-induced hippocampal neurotoxity in vitro (Pike 2001) as well as exhibiting other neuroprotective effects (Pouliot et al 1996). The epidemiological and experimental data propose a potential role of testosterone in protecting cognitive function and preventing Alzheimer’s disease.
After bombarding consumers with advertising, and massaging physicians with free meals and medical "information," the stage is set to seal the deal. "The fat guy has been seeing the ads on TV," said Fugh-Berman. "The doc has just come from a medical meeting where they were talking about how using testosterone can fight depression, etc., and they are being primed in a different way." 

In the U.S., where millions watch the Super Bowl simply to see the clever and costly commercials, and where pharmaceuticals with potentially deadly side effects are pushed on the public at every turn, it's probably not surprising that ads for "Low T" are now splayed across billboards in Florida, with its huge number of older residents, or that a chain of "Low T Centers" has sprung up in Texas and around the heartland.
Conflicting results have been obtained concerning the importance of testosterone in maintaining cardiovascular health.[29][30] Nevertheless, maintaining normal testosterone levels in elderly men has been shown to improve many parameters that are thought to reduce cardiovascular disease risk, such as increased lean body mass, decreased visceral fat mass, decreased total cholesterol, and glycemic control.[31]
The participants were seen every 4 weeks. Blood was taken to measure hormone levels, and questionnaires were given to assess physical function, health status, vitality, and sexual function. Body fat and muscle measurements were also taken at the beginning and end of the 16 weeks. The study was funded in part by NIH’s National Institute on Aging (NIA) and National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Results appeared in the September 12, 2013, issue of the New England Journal of Medicine.
Recently, a panel with cooperation from international andrology and urology societies, published specific recommendations with regard to the diagnosis of Late-onset Hypogonadism (Nieschlag et al 2005). These are summarized in the following text. It is advised that at least two serum testosterone measurements, taken before 11 am on different mornings, are necessary to confirm the diagnosis. The second sample should also include measurement of gonadotrophin and prolactin levels, which may indicate the need for further investigations for pituitary disease. Patients with serum total testosterone consistently below 8 nmol/l invariably demonstrate the clinical syndrome of hypogonadism and are likely to benefit from treatment. Patients with serum total testosterone in the range 8–12 nmol/l often have symptoms attributable to hypogonadism and it may be decided to offer either a clinical trial of testosterone treatment or to make further efforts to define serum bioavailable or free testosterone and then reconsider treatment. Patients with serum total testosterone persistently above 12 nmol/l do not have hypogonadism and symptoms are likely to be due to other disease states or ageing per se so testosterone treatment is not indicated.
The participants were seen every 4 weeks. Blood was taken to measure hormone levels, and questionnaires were given to assess physical function, health status, vitality, and sexual function. Body fat and muscle measurements were also taken at the beginning and end of the 16 weeks. The study was funded in part by NIH’s National Institute on Aging (NIA) and National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Results appeared in the September 12, 2013, issue of the New England Journal of Medicine.
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]
Patients with both ED and cardiovascular disease who receive treatment with an oral PDE5 inhibitor require education regarding what to do if anginal episodes develop while the drug is in their system. Such education includes stressing the importance of alerting emergency care providers to the presence of the drug so that nitrate treatment is avoided.
^ Jump up to: a b Lazaridis I, Charalampopoulos I, Alexaki VI, Avlonitis N, Pediaditakis I, Efstathopoulos P, Calogeropoulou T, Castanas E, Gravanis A (2011). "Neurosteroid dehydroepiandrosterone interacts with nerve growth factor (NGF) receptors, preventing neuronal apoptosis". PLoS Biol. 9 (4): e1001051. doi:10.1371/journal.pbio.1001051. PMC 3082517. PMID 21541365.
The neurovascular events that ultimately occur result in the inhibition of adrenergic tone and the release of the nonadrenergic, noncholinergic neurotransmitter, nitric oxide. Nitric oxide is believed to be released from nonadrenergic, noncholinergic nerves and endothelial cells. It subsequently stimulates the guanylate cyclase enzyme system in penile smooth muscle. This results in increased levels of cyclic guanosine monophosphate (cGMP) and ultimately in smooth muscle relaxation, enhancement of arterial inflow, and veno-occlusion, producing adequate firmness for sexual activity.
There are relatively few contraindications to the use of vacuum devices. Some conditions can predispose to priapism or perhaps bleeding with constriction, such as sickle cell disease, polycythemia, and other blood dyscrasias. Patients taking anticoagulants can safely use vacuum constriction devices but need to accept a higher risk of bleeding (ecchymosis). Good manual dexterity is also needed to use the device; if manual dexterity is impaired, a willing sexual partner can learn to apply the device.
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).
The device consists of an acrylic cylinder placed over the penis that uses a lubricant to achieve a good seal between the penile body and cylinder. An erection is then achieved by creating a vacuum inside the cylinder with a pump connected to the cylinder. Once an erection is achieved, a constriction band is applied to the base of the penis to maintain the erection. The cylinder can then be removed and the patient can engage in intercourse with the constriction band at the base of the penis maintaining the erection. The band can remain on for approximately 30 minutes and then must be removed. The erection produced by the device differs from a normal erection likely because of venous occlusion from the constriction band resulting in generalized swelling of the entire penis, with probable preservation of arterial inflow.

Erectile dysfunction is known to be associated with general health status, thus, lifestyle modification improves erectile function and decreases the rate of decline of function with aging. One year after discontinuation of smoking, patients were found to have a 25% improvement in erectile quality.16 In addition, multivariate analysis found obesity is associated with erectile dysfunction with an approximately 50% increase in ED in obese men as compared with normal weight men.17
Unlike women, who experience a rapid drop in hormone levels at menopause, men experience a more gradual decrease of testosterone levels over time. The older the man, the more likely he is to experience below-normal testosterone levels. Men with testosterone levels below 300 ng/dL may experience some degree of low T symptoms. Your doctor can conduct a blood test and recommend treatment if needed. They can discuss the potential benefits and risks of testosterone medication, as well.
Diabetes is an example of an endocrine disease that can cause a person to experience impotence. Diabetes affects the body’s ability to utilize the hormone insulin. One of the side effects associated with chronic diabetes is nerve damage. This affects penis sensations. Other complications associated with diabetes are impaired blood flow and hormone levels. Both of these factors can contribute to impotence.
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