However, testosterone is only one of many factors that aid in adequate erections. Research is inconclusive regarding the role of testosterone replacement in the treatment of erectile dysfunction. In a review of studies that looked at the benefit of testosterone in men with erection difficulties, nearly half showed no improvement with testosterone treatment. Many times, other health problems play a role in erectile difficulties. These can include:
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]
Male hypogonadism becomes more common with increasing age and is currently an under-treated condition. The diagnosis of hypogonadism in the aging male requires a combination of symptoms and low serum testosterone levels. The currently available testosterone preparations can produce consistent physiological testosterone levels and provide for patient preference.
Men with medical conditions that may cause a sustained erection, such as sickle cell anemia, leukemia, or multiple myeloma, or a man who has an abnormally-shaped penis, may not benefit from these medications. Also, men with liver diseases or a disease of the retina, such as macular degeneration or retinitis pigmentosa, may not be able to take these medications, or may need to take the lowest dosage.
Impotence, also known as erectile dysfunction or ED, is a condition in which a man is unable to get or hold an erection long enough to have a satisfactory sex life. Impotence is a common problem, affecting up to half of Australian men between the ages of 40 and 70 years. The risk of developing erectile dysfunction increases as you get older.In the past, doctors considered impotence to be a mainly psychological problem, caused by performance anxiety or stress. Now, doctors know that many cases of impotence have a physical cause, which usually can be treated. Often, a combination of physical and psychological factors contributes to erectile dysfunction.Physical causes of impotencePhysical causes of impotence can include:problems with blood to flow into and out of the penis;damage to the nerves that send signals from the body’s central nervous system to the penis; and, more rarely,a deficiency in testosterone or other hormones.Some medicines can contribute to impotence, as can some types of surgery and radiotherapy treatments.Blocked blood vessels to the penisA very common cause of impotence is when blood flow into the penis is reduced. This can be due to atherosclerosis, also known as hardening of the arteries. In atherosclerosis, the arteries are clogged and narrowed, resulting in reduced blood flow.Risk factors for atherosclerosis include:high cholesterol;high blood pressure;obesity;sleep apnoea;diabetes; andsmoking.If your erection problems are caused by atherosclerosis, there is a chance that the arteries in other parts of your body (e.g. the coronary arteries that supply your heart) are also affected by atherosclerosis. In fact, erection problems may be the first sign that you are at risk of coronary heart disease.Because the arteries to the penis are narrower than those to the heart, you may develop symptoms of erectile dysfunction before you experience any symptoms of heart disease, such as angina. So seeing your doctor about erection problems may be important for your overall physical health.Impotence can also be caused by a blood clot that prevents enough blood from flowing into the penis to cause an erection.Venous leakageIn some men, blood can flow in to the penis easily, but the problem is that it leaks out again, so an erection cannot be sustained. This is called venous leakage. Doctors aren’t certain of the cause of venous leakage, but they can perform surgery to help repair it.Medicines that can cause impotenceMany medicines can cause erection problems as a side effect, including:diuretics (sometimes known as ‘water tablets’ - often used for high blood pressure);high blood pressure medications;cholesterol-lowering medicines (including statins);some types of antipsychotics;antidepressants;cancer treatments;some medicines used to treat heartburn and stomach ulcers;antihistamines;some pain medicines; andcertain epilepsy medications.If you experience impotence after starting a new medication, tell your doctor, who may be able to prescribe a different medicine for you. Don’t stop taking a medicine without first consulting your doctor. You should also tell your doctor about any over-the-counter medicines or complementary remedies you may be taking.The following table contains a list of specific medicines that may cause or contribute to erectile dysfunction. This list may not cover all types of medicines that can cause erectile dysfunction, so always ask your doctor if you are in doubt. Also, for some of these medicines ED is a very rare side effect. Most men taking these medicines do not experience erectile dysfunction.Medicines that may cause erectile dysfunctionType of medicineExamplesACE inhibitorscaptopril (Capoten), enalapril (Renitec), perindopril (Perindo), ramipril (Tritace), and othersAntidepressantsamitriptyline (Endep), clomipramine (Anafranil), desvenlafaxine (Pristiq), fluoxetine (Prozac), paroxetine (Aropax), sertraline (Zoloft), venlafaxine (Altven, Efexor), and othersAnti-epilepticsclonazepam (Rivotril), pregabalin (Lyrica)Antifungalsitraconazole (Sporanox)Anti-ulcer drugscimetidine (Magicul), nizatidine (Tazac), ranitidine (Zantac), and othersBeta-blockerspropranolol (Inderal), metoprolol (Betaloc, Lopresor), and othersOther blood pressure-lowering medicinesclonidine (Catapres), lercanidipine/enalapril (Zan-Extra), losartan (Cozaar), perindopril/amlodipine (Coveram), olmesartan/amlodipine (Sevikar), telmisartan/amlodipine (Twynsta), valsartan/hydrochlorothiazide (Co-Diovan)Calcium-channel blockersdiltiazem (Cardizem), felodipine (Plendil), nifedipine (Adalat)Cholesterol-lowering drugsatorvastatin (Lipitor), ezetimibe/simvastatin (Vytorin), fluvastatin (Lescol, Vastin), gemfibrozil (Ausgem), pravastatin (Pravachol), simvastatin (APO-simvastatin, Lipex, Zocor), and othersDiuretics ('water tablets')bumetanide (Burinex), chlorthalidone (Hygroton), spironolactone (Aldactone), and othersSchizophrenia drugsamisulpride (Solian, Sulprix), haloperidol (Haldol, Serenace), olanzapine (Lanzek, Ozin, Zypine, Zyprexa), paliperidone (Invega), risperidone (Rispa, Risperdal), ziprasidone (Zeldox)Combination cholesterol-lowering and anti-hypertensiveamlodipine/atorvastatin (Caduet, Cadatin)Pain medicinesfentanyl (Denpax, Durogesic), hydromorphone (Jurnista), morphine (Momex SR, MS Contin), oxycodone (OxyContin, OxyNorm, Targin), tramadolMiscellaneousoestrogens, antiandrogens, anticancer drugs and some chemotherapy treatments, baclofen (Clofen, Lioresal); cyproterone (Androcur, Cyprohexal, Cyprostat), degarelix (Firmagon), etoricoxib (Arcoxia), finasteride (Proscar and Propecia), flutamide (Flutamin), rotigotine (Neupro), triptorelin (Diphereline)*The names in brackets are just some examples of the trade names each specific medicine is marketed under in Australia. The medicine may also be known by other trade names.Diabetes and erectile dysfunctionMen who have diabetes have a higher risk of developing impotence than other men. Diabetes contributes to impotence because it can damage blood vessels and cause a type of nerve damage known as peripheral neuropathy.Hormones and impotenceLow levels of the male hormone, testosterone, are more commonly linked to a lowered sex drive, rather than impotence itself. Only a small percentage of cases of impotence are caused by hormone deficiency.Low testosterone levels may be the result of a condition called hypogonadism, in which the testicles don’t produce enough testosterone. More rarely, low testosterone can be caused by the pituitary (a small gland at the base of the brain) not secreting sufficient hormones to stimulate the testes to produce testosterone. The pituitary is also sometimes affected by small benign (non-cancerous) tumours that secrete prolactin, another hormone that can cause impotence.Mildly decreased levels of testosterone are often not due to specific testicular or pituitary problems, but rather stress or depression. In this situation, testosterone replacement is rarely of any benefit.Other hormone problems, including thyroid disease, can also cause impotence.Prostate cancer and erectile dysfunctionThe advanced stages of prostate cancer can affect the nerves and arteries that are vital for an erection.Radiation treatment for prostate cancer can harm the erectile tissues of the penis, and prostate cancer surgery can cause nerve or artery damage to the penis.Treatment for advanced prostate cancer often includes medicines that counteract testosterone, and commonly cause erectile dysfunction as well as loss of sexual interest.Peyronie’s diseasePeyronie’s disease is an uncommon condition that affects a man’s sex life because his penis curves abnormally and causes pain when he has an erection. He might also be unable to have a hard erection. The curvature of the penis is caused by a scar, called a plaque, that forms in the penis.Other physical causes of impotenceSeveral other factors and conditions can contribute to erectile dysfunction, including the following.Depression. Many men find that when they’re suffering from depression, they lose interest in sex and can’t get or keep an erection. Asking your doctor for treatments for depression may help alleviate your erection problems as well.Smoking contributes to vascular disease (disease of the blood vessels), so it can contribute to erectile dysfunction by affecting blood flow to the penis. Giving up smoking often has a beneficial effect on erectile function.Excessive alcohol use. Alcoholism can cause permanent nerve damage, resulting in impotence. This nerve damage is called peripheral neuropathy. Long-term alcohol use can impair the liver’s ability to function, resulting in a hormone imbalance in which a man has too much of the female sex hormone, oestrogen. On a day-to-day level, alcohol dulls the central nervous system, adversely affecting sexual response.Illicit drug use. Illicit drugs such as marijuana, cocaine, heroin, barbiturates, and amphetamines act on the central nervous system, impairing the body’s ability to respond sexually.Certain exercises. Nerve and artery damage can be caused by prolonged cycling, rodeo riding, or use of a rowing machine, resulting in the inability to get an erection. Often, minimising the use of hard bicycle seats and exercise machine seats, as well as correct positioning of the seat, will help restore sexual function.Surgery to organs near the nerve pathways of the penis, such as the bladder, rectum and prostate, can cause nerve or artery damage to the penis, resulting in the inability to have an erection.Injuries. Impotence can be caused by spinal cord injury; injury to your sex organs; or a pelvic fracture, which can cause damage to the nerves of the penis, or damage the blood vessels, resulting in reduced blood flow to the penis.Conditions affecting the nervous system. Multiple sclerosis (MS) and other degenerative diseases of the nervous system, such as Parkinson’s disease, can damage the nerves involved in erections.Psychological causes of impotenceMost cases of impotence have physical causes, but, in some men, psychological factors are the main contributors to impotence.Impotence that’s triggered by psychological factors is more common in men who are sexually inexperienced. Psychological erectile dysfunction may only occur when you’re with just one particular person. You’re also more likely to have morning erections, and be able to have an erection when you masturbate, than men whose impotence has a physical cause.Here are some psychological factors that can have an impact on your erections.Stress and anxietyWhen you’re stressed and focusing on other issues apart from sex, you might find that you don’t want to have sex as often and there might be a drop in your ability to perform when you do try. You might find that tackling the source of your stress can have benefits in the bedroom as well.Fear of failureAnxiety about your sexual prowess (commonly called performance anxiety) can, in itself, contribute to failure. By putting pressure on yourself, you become too anxious to get an adequate erection.Most men experience isolated episodes of erectile failure. Even when the transient physical cause has passed, anxiety that it may recur is sufficient to prevent erection. Anxiety, whether about something specifically sexual or part of a wider anxiety syndrome, is never helpful to good sexual function.Problems with your relationship and impotenceImpotence may be a manifestation of a poor relationship, or a problematic time in a relationship. Sexual boredom, tension or anger among partners, and lack of intimacy and communication are all possible triggers of erectile dysfunction. In these cases, seeing a counsellor may help.It’s worth remembering that impotence is a complex medical condition, which may have more than one cause. For example, if impotence is the result of a side effect of medicine or an underlying disease, the anxiety caused by lack of performance may perpetuate the erectile dysfunction even after the physical cause has been dealt with.Almost any chronic (ongoing) physical or mental health disorder, including those with no direct effect on penile nerves or blood supply, can have a powerful effect on sexuality, sexual self-image and erectile function.If you’re worried about your sexual response or the quality of your erections, don’t be afraid to talk to your doctor, who has access to treatments that can help. Last Reviewed: 16 December 2016
Having erection trouble from time to time isn't necessarily a cause for concern. If erectile dysfunction is an ongoing issue, however, it can cause stress, affect your self-confidence and contribute to relationship problems. Problems getting or keeping an erection can also be a sign of an underlying health condition that needs treatment and a risk factor for heart disease.
The partial synthesis in the 1930s of abundant, potent testosterone esters permitted the characterization of the hormone's effects, so that Kochakian and Murlin (1936) were able to show that testosterone raised nitrogen retention (a mechanism central to anabolism) in the dog, after which Allan Kenyon's group[183] was able to demonstrate both anabolic and androgenic effects of testosterone propionate in eunuchoidal men, boys, and women. The period of the early 1930s to the 1950s has been called "The Golden Age of Steroid Chemistry",[184] and work during this period progressed quickly. Research in this golden age proved that this newly synthesized compound—testosterone—or rather family of compounds (for many derivatives were developed from 1940 to 1960), was a potent multiplier of muscle, strength, and well-being.[185]
However, testosterone is only one of many factors that aid in adequate erections. Research is inconclusive regarding the role of testosterone replacement in the treatment of erectile dysfunction. In a review of studies that looked at the benefit of testosterone in men with erection difficulties, nearly half showed no improvement with testosterone treatment. Many times, other health problems play a role in erectile difficulties. These can include:
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
Conditions that may be associated with ED include diabetes, [25, 26, 27] hypertension, [28] , and CAD, as well as neurologic disorders, endocrinopathies, benign prostatic hyperplasia, [29] , sleep apnea [30] , COPD, [31] and depression (see Table 1 below). [32, 33, 34, 35] In fact, almost any disease may affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the corpora cavernosa or influence the patient’s psychological mood and behavior.
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.
Lifestyle choices that impair blood circulation can contribute to ED. Smoking, excessive drinking, and drug abuse may damage the blood vessels and reduce blood flow to the penis. Smoking makes men with atherosclerosis particularly vulnerable to ED. Being overweight and getting too little exercise also contribute to ED.  Studies indicate that men who exercise regularly have a lower risk of ED.
In the hepatic 17-ketosteroid pathway of testosterone metabolism, testosterone is converted in the liver by 5α-reductase and 5β-reductase into 5α-DHT and the inactive 5β-DHT, respectively.[1][147] Then, 5α-DHT and 5β-DHT are converted by 3α-HSD into 3α-androstanediol and 3α-etiocholanediol, respectively.[1][147] Subsequently, 3α-androstanediol and 3α-etiocholanediol are converted by 17β-HSD into androsterone and etiocholanolone, which is followed by their conjugation and excretion.[1][147] 3β-Androstanediol and 3β-etiocholanediol can also be formed in this pathway when 5α-DHT and 5β-DHT are acted upon by 3β-HSD instead of 3α-HSD, respectively, and they can then be transformed into epiandrosterone and epietiocholanolone, respectively.[149][150] A small portion of approximately 3% of testosterone is reversibly converted in the liver into androstenedione by 17β-HSD.[148]

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.
An international consensus document was recently published and provides guidance on the diagnosis, treatment and monitoring of late-onset hypogonadism (LOH) in men. The diagnosis of LOH requires biochemical and clinical components. Controversy in defining the clinical syndrome continues due to the high prevalence of hypogonadal symptoms in the aging male population and the non-specific nature of these symptoms. Further controversy surrounds setting a lower limit of normal testosterone, the limitations of the commonly available total testosterone result in assessing some patients and the unavailability of reliable measures of bioavailable or free testosterone for general clinical use. As with any clinical intervention testosterone treatment should be judged on a balance of risk versus benefit. The traditional benefits of testosterone on sexual function, mood, strength and quality of life remain the primary goals of treatment but possible beneficial effects on other parameters such as bone density, obesity, insulin resistance and angina are emerging and will be reviewed. Potential concerns regarding the effects of testosterone on prostate disease, aggression and polycythaemia will also be addressed. The options available for treatment have increased in recent years with the availability of a number of testosterone preparations which can reliably produce physiological serum concentrations.
The partial synthesis in the 1930s of abundant, potent testosterone esters permitted the characterization of the hormone's effects, so that Kochakian and Murlin (1936) were able to show that testosterone raised nitrogen retention (a mechanism central to anabolism) in the dog, after which Allan Kenyon's group[183] was able to demonstrate both anabolic and androgenic effects of testosterone propionate in eunuchoidal men, boys, and women. The period of the early 1930s to the 1950s has been called "The Golden Age of Steroid Chemistry",[184] and work during this period progressed quickly. Research in this golden age proved that this newly synthesized compound—testosterone—or rather family of compounds (for many derivatives were developed from 1940 to 1960), was a potent multiplier of muscle, strength, and well-being.[185]
Male hypogonadism becomes more common with increasing age and is currently an under-treated condition. The diagnosis of hypogonadism in the aging male requires a combination of symptoms and low serum testosterone levels. The currently available testosterone preparations can produce consistent physiological testosterone levels and provide for patient preference.
Many experts believe that atrophy, a partial or complete wasting away of tissue, and fibrosis, the growth of excess tissue, of the smooth muscle tissue in the body of the penis (cavernous smooth muscle) triggers problems with being able to maintain a firm erection. Poor ability to maintain an erection is often an early symptom of erectile dysfunction. Although the condition is called venous leak, the real problem is not with the veins but malfunction of the smooth muscle that surrounds the veins. The end result is difficulty with maintain a firm erection (losing an erection too quickly) that is now believe to be an early manifestation of atherosclerosis and vascular disease.
The medications are extremely effective, which is very good. And the medications are, for the most part, extremely well-tolerated. But there are, like with any medications, a potential downside. The one absolute downside to the use of any of these erection what we call PDE5 medications is if a patient is using a nitroglycerin medication. And nitroglycerins are used for heart disease and for angina, for the most part, although there are some recreational uses of nitrites. And that’s important because your blood vessels will dilate and your blood pressure will drop. And that is an absolute contraindication.
Total levels of testosterone in the body are 264 to 916 ng/dL in men age 19 to 39 years,[161] while mean testosterone levels in adult men have been reported as 630 ng/dL.[162] Levels of testosterone in men decline with age.[161] In women, mean levels of total testosterone have been reported to be 32.6 ng/dL.[163][164] In women with hyperandrogenism, mean levels of total testosterone have been reported to be 62.1 ng/dL.[163][164]

This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.


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.
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]
Some of the effects of testosterone treatment are well recognised and it seems clear that testosterone treatment for aging hypogonadal men can be expected to increase lean body mass, decrease visceral fat mass, increase bone mineral density and decrease total cholesterol. Beneficial effects have been seen in many trials on other parameters such as glycemic control in diabetes, erectile dysfunction, cardiovascular risk factors, angina, mood and cognition. These potentially important effects require confirmation in larger clinical trials. Indeed, it is apparent that longer duration randomized controlled trials of testosterone treatment in large numbers of men are needed to confirm the effects of testosterone on many aspects of aging male health including cardiovascular health, psychiatric health, prostate cancer and functional capacity. In the absence of such studies, it is necessary to balance risk and benefit on the best available data. At the present time the data supports the treatment of hypogonadal men with testosterone to normalize testosterone levels and improve symptoms. Most men with hypogonadism do not have a contraindication to treatment, but it is important to monitor for adverse consequences including prostate complications and polycythemia.
Failure to achieve an erection is not uncommon for most men and may be considered normal even if it happens as often as 20 percent of the time. There is a wide range of normal when it comes to sexual functioning and sexual relationships. "Generally if a couple feels comfortable with their sex life and they enjoy intimacy together, erectile dysfunction may not be much of an issue. But if erectile dysfunction is causing stress in a relationship, then help is available," says Feloney.
Additionally, the physiologic processes involving erections begin at the genetic level. Certain genes become activated at critical times to produce proteins vital to sustaining this pathway. Some researchers have focused on identifying particular genes that place men at risk for ED. At present, these studies are limited to animal models, and little success has been reported to date. [4] Nevertheless, this research has given rise to many new treatment targets and a better understanding of the entire process.

These "disease-awareness" campaigns—ostensibly a public service intended to educate those potentially at risk about a condition they may not even have heard of but "could" have—are subtle, even insidious. They may not mention a specific product, but a bit of sleuthing reveals that their sponsors are usually pharmaceutical companies that "just happen" to manufacture products used to treat the real (or at least alleged) condition.
A vacuum erection device is a plastic tube that slips over the penis, making a seal with the skin of the body. A pump at the other end of the tube makes a low-pressure vacuum around the erectile tissue, which results in an erection. An elastic ring is then slipped onto the base of the penis. This holds the blood in the penis (and keeps it hard) for up to 30 minutes. With proper training, 75 out of 100 men can get a working erection using a vacuum erection device.
Although her male patients may or may not get the low testosterone diagnosis they believe Dr. Wyne should give them, they will get a comprehensive examination. Besides their testosterone level, she will look at their triglycerides, glucose (blood sugar) tolerance, liver enzymes, and other counts as well as the condition of their testicles. "I need to know if they're normal going into it," she explained.
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.
This is one of many types of constricting devices placed at the base of the penis to diminish venous outflow and improve the quality and duration of the erection. This is particularly useful in men who have a venous leak and are only able to obtain partial erections that they are unable to maintain. These constricting devices may be used in conjunction with oral agents, injection therapy, and vacuum devices.

Men who watch a sexually explicit movie have an average increase of 35% in testosterone, peaking at 60–90 minutes after the end of the film, but no increase is seen in men who watch sexually neutral films.[43] Men who watch sexually explicit films also report increased motivation, competitiveness, and decreased exhaustion.[44] A link has also been found between relaxation following sexual arousal and testosterone levels.[45]
Conditions that may be associated with ED include diabetes, [25, 26, 27] hypertension, [28] , and CAD, as well as neurologic disorders, endocrinopathies, benign prostatic hyperplasia, [29] , sleep apnea [30] , COPD, [31] and depression (see Table 1 below). [32, 33, 34, 35] In fact, almost any disease may affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the corpora cavernosa or influence the patient’s psychological mood and behavior.
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. 
Hypogonadism (as well as age-related low testosterone) is diagnosed with blood tests that measure the level of testosterone in the body. The Endocrine Society recommends testing for suspected low T with a total testosterone test. It may be performed in the morning when testosterone levels tend to be highest in young men, although this isn't necessarily the case in older men. The test may be repeated on another day if the results show a low T level. (5)

Erectile dysfunction - (ED) or impotence is sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual activity. A penile erection is the hydraulic effect of blood entering and being retained in sponge-like bodies within the penis. The process is most often initiated as a result of sexual arousal, when signals are transmitted from the brain to nerves in the penis.
These are not currently approved by the FDA for ED management, but they may be offered through research studies (clinical trials). Patients who are interested should discuss the risks and benefits (informed consent) of each, as well as costs before starting any clinical trials. Most therapies not approved by the FDA are not covered by government or private insurance benefits.
Sexual dysfunction is highly prevalent in men and women. In the MMAS, 52% of the respondents reported some degree of erectile difficulty. Complete ED, defined as (1) the total inability to obtain or maintain an erection during sexual stimulation and (2) the absence of nocturnal erections, occurred in 10% of the respondents. Mild and moderate ED occurred in 17% and 25% of responders, respectively. [15]

It is hard to know how many men among us have TD, although data suggest that overall about 2.1% (about 2 men in every 100) may have TD. As few as 1% of younger men may have TD, while as many as 50% of men over 80 years old may have TD. People who study the condition often use different cut-off points for the numbers, so you may hear different numbers being stated.


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.
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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