Both ED and low testosterone (hypogonadism) increase with age. The incidence of the latter is 40% in men aged 45 years and older.  Testosterone is known to be important in mood, cognition, vitality, bone health, and muscle and fat composition. It also plays a key role in sexual dysfunction (eg, low libido, poor erection quality, ejaculatory or orgasmic dysfunction, reduced spontaneous erections, or reduced sexual activity). 
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.
One study examined the role of testosterone supplementation in hypogonadal men with ED. These men were considered nonresponders to sildenafil, and their erections were monitored by assessing nocturnal penile tumescence (NPT). After these men were given testosterone transdermally for 6 months, the number of NPTs increased, as did the maximum rigidity with sildenafil.  This study suggests that a certain level of testosterone may be necessary for PDE5 inhibitors to function properly.
Psychological factors — Psychological issues such as depression, anxiety, guilt or fear can sometimes cause sexual problems. At one time, these factors were thought to be the major cause of impotence. Doctors now know that physical factors cause impotence in most men with the problem. However, embarrassment or "performance anxiety" can make a physical problem worse.
Erectile dysfunction (ED) can be treated by urologists or other specialists or even by your general practitioner. Your doctor may recommend medication that works by relaxing penis muscles and increasing blood flow into the penis. Other treatments include therapy, implants, surgery and lifestyle changes, like exercising regularly, losing weight and eating right.
Alprostadil may be delivered via the urethra in the form of a pellet (MUSE) (107). This form of therapy has been trialed in SCI men with intermediate success (108). Bodner trialed MUSE dose escalation in SCI men and found 1,000 μg to be the most effective dose. Several men had hypotension when a constriction ring was not used in conjunction with the MUSE therapy.
The first stem cell study for the treatment of ED was published in 2004. This study used embryonic stem cells to treat ED. At this time, there is a total of 36 published basic studies assessing stem cell therapy for ED, with two clinical trials. The mechanism of action of stem cells is to generate angiogenesis with subsequent increase in cavernosal smooth muscle cells within the corporal bodies.46
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.
Clinical studies have suggested that these devices are effective and acceptable to a large number of patients with ED of varying causes, including psychogenic erectile failure. These devices are safe and can restore a man’s ability to achieve penetrative intercourse, with one study suggesting nearly 95% success with adequate instruction and support.30 However, satisfaction with this treatment modality typically wanes with time, as patients report dissatisfaction with how cumbersome or unnatural the devices are to use, hinging or buckling of the erection with thrusting, and dissatisfaction with the fact that the erection is ischemic and therefore cold, which can be off-putting to the partner.
The observation that TRT enhances the efficacy of PDE5 inhibitors in hypogonadal men taking these therapies with suboptimal response to the PDE5 inhibitors alone has been reported.33 In addition, investigators have demonstrated that TRT in hypogonadal men can improve erectile function even without the benefit of PDE5 inhibitors.33 In addition, guidelines for managing ED in hypogonadal men by the European Association of Urology recommend controlling the man to a eugonadal state prior to initiation of PDE5 inhibitor therapy.36 Testosterone measurement consists of a serum specimen which should be ideally obtained in the morning because of the normal diurnal variation of testosterone which is at its peak in the morning. Since TRT is relatively safe, and men can potentially see an improvement in erectile function, it seems prudent to consider this issue when presented with a patient suffering from ED.
An analysis of 14 studies involving more than 90,000 patients with ED confirmed the relation between ED and an increased risk of cardiovascular events and mortality.  Compared with patients without ED, those with ED had a 44% increased risk of cardiovascular events, a 25% increased risk of all-cause mortality, a 62% increased risk of MI, and a 39% increased risk of cerebrovascular events. Treatment of ED, either through lifestyle interventions or by pharmacologic means, may improve prognosis and reduce risk.
A variety of personal habits and lifestyle choices have been linked to ED. In some ways, this is a good thing, since habits can be broken and choices reconsidered. What's more, many of the lifestyle factors that contribute to sexual problems are ones that affect overall health and well-being, both physical and mental. Addressing these factors, therefore, can have benefits beyond improving erectile dysfunction.
Martha K Terris, MD, FACS is a member of the following medical societies: American Cancer Society, American College of Surgeons, American Institute of Ultrasound in Medicine, American Society of Clinical Oncology, American Urological Association, Association of Women Surgeons, New York Academy of Sciences, Society of Government Service Urologists, Society of University Urologists, Society of Urology Chairpersons and Program Directors, and Society of Women in Urology
Since endothelial dysfunction, CVD and ED are closely associated in epidemiological studies, the question for clinicians is whether to recommend the man presenting with ED undergo a cardiovascular (CV) evaluation. Clearly, based on numerous studies, ED can be considered at least a ‘marker’ for possible further vascular disease or CVD.15 In their report, Vlachopoulos and coworkers make the point that the man presenting with ED, the clinician, is offered an opportunity to attempt to improve the health of the man by addressing lifestyle modification, and consider further vascular evaluation owing to the clear relationship between endothelial dysfunction, ED and CVD.19
One study by Palmer and colleagues evaluated sildenafil use in SB males with thoracic lesions (76). A prospective, blinded, randomized, placebo-controlled, dose-escalation, crossover study in 17 patients with SB and ED was performed. All study participates took sets of tablet in groups, two sets of placebo, one of 25 mg, and the last 50 mg. Overall response to the tablet sets was measured by IIEF response and self-report of erectile rigidity. Patients reported that taking 50 mg of sildenafil led to improved erections, duration of erections, frequency of erections and level of confidence compared to sildenafil 25 mg and more significantly compared to placebo. Of the five patients who reported side effects, two experienced mild hematological changes that reverted to baseline after study completion.
Although not proven, it is likely that erectile dysfunction can be prevented by good general health, paying particular attention to body weight, exercise, and cigarette smoking. For example, heart disease and diabetes are problems that can cause erectile dysfunction, and both are preventable through lifestyle changes such as sensible eating and regular exercise. Furthermore, early diagnosis and treatment of associated conditions like diabetes, hypertension and high cholesterol may prevent or delay erectile dysfunction, or stop the erectile dysfunction from getting more serious.
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.
Some men should not take PDE5 inhibitors. They can cause hypotension (abnormally low blood pressure that can lead to fainting and even shock) when given to patients who are taking nitrates (medications taken for heart disease). Therefore, patients taking nitrates daily should not take any of the PDE5 inhibitors. Nitrates relieve angina (chest pain due to insufficient blood supply to the heart muscle because of narrowing of the coronary arteries); these include nitroglycerine tablets, patches, ointments, sprays, and pastes, as well as isosorbide dinitrate and isosorbide mononitrate. Other nitrates such as amyl nitrate and butyl nitrate also are in some recreational drugs called "poppers."
Her remark was entirely destructive of poetry, since it was to the effect that poetry had nothing whatever to do with her; all her friends spent their lives in making up phrases, she said; all his feeling was an illusion, and next moment, as if to taunt him with his impotence, she had sunk into one of those dreamy states which took no account whatever of his existence.
When other treatments haven’t helped, a penile implant may be the right solution. A penile implant is a medical device that is surgically placed into a penis to mimic the look and performance of a natural erection9. Implants are custom-fitted to your anatomy. Sensitivity and the ability to ejaculate aren’t typically affected either, so you’ll be able to have an orgasm normally (unless you have a medical condition that prevents this)7.
Acupuncture may help treat psychological ED, though studies are limited and inconclusive. You’ll likely need several appointments before you begin to notice any improvements. When choosing an acupuncturist, look for a certified practitioner who uses disposable needles and follows U.S. Food and Drug Administration guidelines for needle disposal and sterilization.
The inflatable type of device consists of cylinders that are implanted in the corpora cavernosa, a fluid reservoir implanted in the abdomen, and a pump placed in the scrotum. The man squeezes the pump to move fluid into the cylinders and cause them to become rigid. (He reverses the process by squeezing the pump again.) While these devices allow for intermittent erections, they have a slightly higher malfunction rate than the silicon rods.