Erectile dysfunction (ED) is commonly called impotence. It’s a condition in which a man can’t achieve or maintain an erection during sexual performance. Symptoms may also include reduced sexual desire or libido. Your doctor is likely to diagnose you with ED if the condition lasts for more than a few weeks or months. ED affects as many as 30 million men in the United States.
Something else to consider is your porn use. If you are masturbating to very stimulating porn on a regular basis then it might be difficult to get as aroused in the bedroom with your partner. Watching video pornography is very stimulating and often men have difficulty creating that same level of arousal or stimulation with their partners. Consider masturbating without technology as visual images in your head are less stimulating then watching something live. Try this for two weeks and see if your erection quality improves.
Oral PDE5i remains the first line treatment for NED from SCI. Three of the four PDE5i currently available in the U.S., avanafil excluded, have been investigated in the SCI, and all of the more recent studies have shown improvements in erectile function based on IIEF score compared to placebo when included (59-63). Other studies have also shown significant improvements in the IIEF score when compared to baseline (64-69). Furthermore, treatment efficacy when compared to placebo occurs despite LOI or American Spinal Injury Association (ASIA) score characterizing impairment related to the injury (59,61).
Monitoring erections that occur during sleep (nocturnal penile tumescence) can help you and your doctor to understand if the erectile dysfunction is due to psychological or physical causes. The nocturnal penile tumescence test is a study to evaluate erections at night. Normally men have three to five erections per eight hours of sleep. The test can be performed at home or in a sleep lab. The most accurate way to perform the test involves a special device that is connected to two rings. The rings are placed around the penis, one at the tip of the penis and the other at the bottom (base) of the penis. The device records how many erections occur, how long they last, and how rigid they are. The test is limited in that it does not assess the ability to penetrate.
2 inability of the adult male to achieve or sustain a penile erection or, less commonly, to ejaculate after achieving an erection. Several forms are recognized. Functional impotence has a psychological basis. Organic impotence includes vasculogenic, neurogenic, endocrinic, and anatomical factors. Anatomical impotence results from physically defective genitalia. Atonic impotence involves disturbed neuromuscular function. Poor health, old or advancing age, drugs, smoking, trauma, and fatigue can induce impotence. Also called erectile dysfunction, impotency. impotent, adj.
Melanocortin receptor agonists were found to induce erections serendipitously. A study investigating the dermatologic use of Melanotan-II (MT-II) was found to generate erections unexpectedly leading to the development of MTII derivatives for ED treatment (120). MT-II was initially used to induce pigment changes in the skin for artificial tanning but has been suspected to induce melanoma, however (121).
It appears that testosterone has NOS-independent pathways as well. In one study, castrated rats were implanted with testosterone pellets and then divided into a group that received an NOS inhibitor (L-nitro-L-arginine methyl ester [L-NAME]) and a control group that received no enzyme.  The castrated rats that were given testosterone pellets and L-NAME still had partial erections, a result suggesting the presence of a pathway independent of NOS activity.
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). 
For many men, stopping smoking is an erectile dysfunction remedy, particularly when ED is the result of vascular disease, which occurs when blood supply to the penis becomes restricted because of blockage or narrowing of the arteries. Smoking and even smokeless tobacco can also cause the narrowing of important blood vessels and have the same negative impact.
Erections are initiated and maintained via integration of afferent inputs in the supra sacral regions of the central nervous system. Regions of the brain cited to have key roles in the integration of signals include the medial amygdala, MPOA, periaqueductal gray matter, paraventricular nucleus (PVN), and ventral tegmentum among others (16). Studies in animal models, particularly in rats, have been paramount in identifying these key areas of signal integration and control. Electrostimulation of the MPOA, PVN and hippocampus lead to erection and lesions in these areas may prevent erection (17). Marson et al. injected labeled pseudorabies virus into rat corpora cavernosa and traced them to neurons in the spinal cord, brain stem and hypothalamus (18). Stimulation of the rat dorsal nerve led to increased firing in the MPOA not found elsewhere (19). Axonal tracing in animals have shows direct projections from the hypothalamus to the lumbosacral autonomic erection centers. Oxytocin and vasopressin have been identified as central neurotransmitters within the hypothalamic nuclei and may have a role in penile erection (17). These signaling studies identifying key areas of erectile response integration may explain how ED is associated with cerebrovascular accident (CVA), Parkinson’s, epilepsy and MS.
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
Infection is a concern after placement of a penile prosthesis and is reported as a complication in up to 20% of men undergoing placement of a penile prosthesis. If the device becomes infected more commonly, it needs to be removed. Another prosthesis can be placed after the infection is treated and the penile tissues have healed, but it is a difficult surgery. Erosion of the prosthesis, whereby it compresses through the corporal tissue, into the urethra may occur. Symptoms include pain, blood in the urine, discharge, abnormal stream, and malfunction of the prosthesis. If the prosthesis erodes, it will need to be removed. A catheter is placed to allow the urethra to heal.
Erectile dysfunction (ED) affects 50% of men older than 40 years,  exerting substantial effects on quality of life.  This common problem is complex and involves multiple pathways. Penile erections are produced by an integration of physiologic processes involving the central nervous, peripheral nervous, hormonal, and vascular systems. Any abnormality in these systems, whether from medication or disease, has a significant impact on the ability to develop and sustain an erection, ejaculate, and experience orgasm.
The penis contains three cylinders, the two corpora cavernosa, which are on the top of the penis (see figure 1 below). These two cylinders are involved in erections. The third cylinder contains the urethra, the tube that the urine and ejaculate passes through, runs along the underside of the penis. The corpus spongiosum surrounds the urethra. Spongy tissue that has muscles, fibrous tissues, veins, and arteries within it makes up the corpora cavernosa. The inside of the corpora cavernosa is like a sponge, with potential spaces that can fill with blood and distend (known as sinusoids). A layer of tissue that is like Saran Wrap, called the tunica albuginea, surrounds the corpora. Veins located just under the tunica albuginea drain blood out of the penis.
Surgical intervention for a number of conditions may remove anatomical structures necessary to erection, damage nerves, or impair blood supply. Erectile dysfunction is a common complication of treatments for prostate cancer, including prostatectomy and destruction of the prostate by external beam radiation, although the prostate gland itself is not necessary to achieve an erection. As far as inguinal hernia surgery is concerned, in most cases, and in the absence of postoperative complications, the operative repair can lead to a recovery of the sexual life of people with preoperative sexual dysfunction, while, in most cases, it does not affect people with a preoperative normal sexual life.
The dorsal artery provides for engorgement of the glans during erection, whereas the bulbourethral artery supplies the bulb and the corpus spongiosum. The cavernous artery effects tumescence of the corpus cavernosum and thus is principally responsible for erection. The cavernous artery gives off many helicine arteries, which supply the trabecular erectile tissue and the sinusoids. These helicine arteries are contracted and tortuous in the flaccid state and become dilated and straight during erection. 
Medication therapy is extremely effective in augmenting the quality of man’s erection such that he is able to have satisfactory intercourse. Indeed medications referred to as phospho-diesterase inhibitors such as Cialis, Viagra, Levitra and Stendra work in 65% of men suffering from erectile dysfunction. Cialis is currently the preferred drug since it is the only one that may be taking on a full stomach and lasts for 36 hours. This favors a more romantic and natural sexual interaction. Planning kills the mood!
Psychosocial problems are important and may cause erectile dysfunction by themselves or together with other causes of erectile dysfunction, such as diabetes and heart disease. Relationships are complicated and many factors cause tensions, which can affect sexual relations. For some men, these problems can become ongoing and it can help to talk through the issue with a skilled counsellor. It is important to know that the longer erectile dysfunction is left untreated, the greater the effect on relationships. This is another reason why early treatment of erectile dysfunction is important.
Induction of erection occurs after stimulation of the cavernous and pelvic nerve plexus. Conversely, stimulation of the sympathetic trunk leads to detumescence. The reflex erectile response requires that the sacral reflex arc remain intact. Tactile and sensory signals are received by the somatic sensory pathways and integrate with parasympathetic nuclei within the sacral spinal cord (S2-4) leading to induction of erection via cholinergic signaling. These reflexogenic erections remain intact with upper motor neuron injuries. Psychogenic erections do not require that the sacral reflex arc remain intact. In a cat models, spinal cord removal below L4/L5 led to absence of a reflexogenic erection but stimulation of the medial preoptic area (MPOA) or placement near a female cat in heat led to erection (5,6). Psychogenic erections occur via induction of central pathways traveling from the brain through the sympathetic chain. Non-penile sensory pathways induced by sight, sound, touch and smell travel through the MPOA to the erection centers within the cord T11-L2, and S2-S4 to induce erections (7). When a sacral lower motor neuron injury is present in men, below T12 these types of erections are more likely to occur (8). Spinal cord lesions above T9 are not associated with psychogenic erections (9). Rigidity of erections is less with psychogenic erections because the thoracolumbar sympathetic outflow may contain a decreased concentration of neurons compared to the parasympathetic outflow from the sacral spinal cord.
Patients receiving penile prostheses should be instructed in the operation of the prosthesis before surgery and again in the postoperative period. The prosthesis usually is not activated until approximately 6 weeks after surgery, so as to allow the edema and pain to subside. The prosthesis is checked in the office before the patient begins to use it.
Other treatment options such as penile self-injection therapy, external vacuum pumps and the medicated urethral system for erection are in rare occasions an effective long-term treatment. Only a very small percentage of men will continue with these treatments as evidenced by a very high drop out rate and a very low refill rate. These treatments require extensive planning which interferes with spontaneity. This may be the reason why the refill rate is so low and the drop out of treatment so high.
Besides PDE5 inhibitors and among second-line therapies are VCDs which are clear plastic chambers placed over the penis, tightened against the lower abdomen with a mechanism to create a vacuum inside the chamber. This directs blood into the penis. If an adequate erection occurs inside the chamber, the patient slips a small constriction band off the end of the VCD and onto the base of the penis. An erection beyond 30 min is not recommended. These devices can be a bit cumbersome, but are very safe.40
MalaCards based summary : Impotence, also known as erectile dysfunction, is related to vasculogenic impotence and hyperprolactinemia, and has symptoms including angina pectoris, pelvic pain and tremor. An important gene associated with Impotence is NOS1 (Nitric Oxide Synthase 1), and among its related pathways/superpathways are Response to elevated platelet cytosolic Ca2+ and Platelet homeostasis. The drugs Methyltestosterone and Testosterone have been mentioned in the context of this disorder. Affiliated tissues include prostate, spinal cord and endothelial, and related phenotypes are normal and reproductive system
NO is produced by the enzyme NO synthase (NOS).  NOS plays many roles, ranging from homeostasis to immune system regulation. To date, 3 subtypes have been identified: nNOS, iNOS, and eNOS, which are produced by the genes NOS1, NOS2, and NOS3, respectively. This nomenclature is derived from the sources of the original isolates: neuronal tissue (nNOS), immunoactivated macrophage cell lines (iNOS), and vascular endothelium (eNOS). The subtypes are not, however, limited to the tissues from which they were first isolated.
While pills for ED are convenient, some men sustain stronger erections by injecting medication directly into the penis. Drugs approved for this purpose work by widening the blood vessels, causing the penis to become engorged with blood. Another option is inserting a medicated pellet into the urethra. The pellet can trigger an erection within 10 minutes.