Total testosterone levels: Health care professionals should obtain a patient's blood samples for total testosterone levels in the early morning (before 8 a.m.) because the testosterone levels go up and down throughout the day. If you have a low testosterone level, a health care professional should check it again to confirm that it is truly low. In some men, a specialized test measuring the active form of testosterone (free or bioavailable testosterone) may be recommended.

© 2019 Healthgrades Operating Company, Inc. The content on Healthgrades does not provide medical advice. Always consult a medical provider for diagnosis and treatment. All rights reserved. May not be reproduced or reprinted without permission from Healthgrades Operating Company, Inc. Use of this information is governed by the Healthgrades User Agreement.


No nitrate-based drugs should be given to men with suspected heart attacks if they have taken PDE5i medications within 24 hours. Combining PDE5i with nitrate-based medications can cause a severe and dramatic drop in blood pressure with potentially very dangerous consequences. This is also why someone should absolutely never share PDE5i medications with anyone else. If they happen to be taking one of the drugs that interacts dangerously with PDE5i medications, the results could be very serious. If there is any question about possible drug interactions, always check with a doctor or pharmacist.
Self-injection of these agents has been of enormous benefit because they represent the most effective way to achieve erections in a wide variety of men who otherwise would be unable to achieve adequate rigid erections. The need for intact nerve pathways to the penile tissue is not needed. The locally injected medication directly relaxes the arteriole vessels and penile cavernosal tissue. Thus, this therapy is not dependent on sexual stimulation.
All NOS subtypes produce NO, but each may play a different biologic role in various tissues. nNOS and eNOS are considered constitutive forms because they share biochemical features: They are calcium-dependent, they require calmodulin and reduced nicotinamide adenine dinucleotide phosphate for catalytic activity, and they are competitively inhibited by arginine derivatives. nNOS is involved in the regulation of neurotransmission, and eNOS is involved in the regulation of blood flow.
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.
Aging: There are two reasons why older men are more likely to experience erectile dysfunction than younger men. First, older men are more likely to develop diseases (such as heart attacks, angina, cardiovascular disease, strokes, diabetes mellitus, and high blood pressure) that are associated with erectile dysfunction. Second, the aging process alone can cause erectile dysfunction in some men by causing changes in the muscle and tissue within the penis.
Picture of penile tumescence monitor. This penile tumescence monitor is placed at the base and near the corona of the penis. It is connected to a monitor that records a continuous graph depicting the force and duration of erections that occur during sleep. The monitor is strapped to the leg. The nocturnal penile tumescence (NPT) test is conducted on several nights to obtain an accurate indication of erections that normally occur during the alpha phase of sleep.

Long-term predictions based on an aging population and an increase in risk factors (eg, hypertension, diabetes, vascular disease, pelvic and prostate surgery, benign prostatic hyperplasia, and lower urinary tract symptoms) suggest a large increase in the number of men with ED. In addition, the prevalence of ED is underestimated because physicians frequently do not question their patients about this disorder.


In a 2005 study, three months of twice-daily sets of kegel exercises combined with biofeedback and advice on lifestyle changes, such as quitting smoking, losing weight, and limiting alcohol, worked far better than just giving the participants advice. “Wearing tight pants will affect impotence along with some other medical conditions like diabetes and heart disease,” which can also affect a man’s degree of impotence, Dr. Jennifer Burns, specializing in family practice with an emphasis on gastrointestinal health at the BienEtre Center, told Medical Daily.
Long-term predictions based on an aging population and an increase in risk factors (eg, hypertension, diabetes, vascular disease, pelvic and prostate surgery, benign prostatic hyperplasia, and lower urinary tract symptoms) suggest a large increase in the number of men with ED. In addition, the prevalence of ED is underestimated because physicians frequently do not question their patients about this disorder.
If conservative treatments for erectile dysfunction are not successful your consultant may recommend penile prosthetic surgery. A penile prosthetic is an implant that allows men with erectile dysfunction to have an erection. Prosthetics may also be used for patients with Peyronie’s disease. There are several types of penile implants. Your consultant will assess your own situation and recommend the implant that meets your needs.
Many common medications for treating hypertension, depression, and high blood lipids (high cholesterol) can contribute to erectile dysfunction (see above). Treatment of hypertension is an example. There are many different types (classes) of medications for high blood pressure; these include beta-blockers, calcium channel blockers, diuretics (medications that increase urine volume), angiotensin converting enzyme inhibitors (ACE inhibitors), and angiotensin receptor blockers (ARBs). Patients may use these medications alone or in combination to control blood pressure. Some of these medications can cause troubles with erections. For example, Inderal (a beta-blocker) and hydrochlorothiazide (a diuretic) cause erectile dysfunction, while calcium channel blockers and ACE inhibitors do not seem to affect erectile function. On the other hand, other medications (such as angiotensin receptor blockers [ARB] including losartan [Cozaar] and valsartan [Diovan]) may actually help with erections. Therefore, if possible, you may benefit from changing your medications, but this requires approval by your prescribing health care provider.

Alprostadil may also be administered into the urethral opening of the penis. In MUSE (medical urethral system for erection), the man inserts a thin tube the width of a vermicelli noodle into his urethral opening and presses down on a plunger to deliver a tiny pellet containing alprostadil into his penis. The drug takes about 10 minutes to work and the erection lasts about an hour. The main side effect is a sensation of pain and burning in the urethra, which can last about five to 15 minutes.


The U.S. FDA (Food and Drug Administration) has a list of 29 OTC products that claim to treat erectile dysfunction. Patients should avoid these because many contain harmful ingredients. Other natural or herbal remedies such as DHEA, L-arginine, ginseng, and yohimbe are supplements that have been used but have not been proven safe and effective according to some researchers. Before using such compounds, individuals should consult their doctor. According to some experts, acupuncture does not effectively treat erectile dysfunction. Other home remedies for reducing ED symptoms include diet changes such as eating blueberries and citrus fruits and drinking red wine.

On the horizon is gene therapy that would deliver genes that produce products or proteins that may not be functioning properly in the penile tissue of men with ED. Replacement of these proteins may result in improvement in erectile function. Experimental animal models have demonstrated improvement in erectile function with gene therapy. Human studies may also demonstrate success with this therapy. Gene therapy may take a long time for regulatory approval and public acceptance.
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.
It is normal for a man to have five to six erections during sleep, especially during rapid eye movement (REM). Their absence may indicate a problem with nerve function or blood supply in the penis. There are two methods for measuring changes in penile rigidity and circumference during nocturnal erection: snap gauge and strain gauge. A significant proportion of men who have no sexual dysfunction nonetheless do not have regular nocturnal erections.
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.
Health Tools Baby Due Date CalculatorBasal Metabolic Rate CalculatorBody Mass Index (BMI) CalculatorCalories Burned CalculatorChild Energy Requirements CalculatorDaily Calcium Requirements CalculatorDaily Fibre Requirements CalculatorIdeal Weight CalculatorInfectious Diseases Exclusion Periods ToolOvulation CalculatorSmoking Cost CalculatorTarget Heart Rate CalculatorWaist-to-hip Ratio Calculator Risk Tests Depression Self-AssessmentErectile Dysfunction ToolMacular Degeneration ToolOsteoporosis Risk TestProstate Symptoms Self-Assessment
Recently, several advances in the uses of stem cells have bet met with great anticipation. Stem cells have the ability to differentiate into different cell lines based on the cellular signaling they receive. Bone marrow mononuclear cells in particular have been used for the treatment of ED in animal models. Yiou et al. recently delivered bone marrow-mononuclear cells (BM-MNC) into the intracavernous smooth muscle of post radical prostatectomy men (123). The open label, dose escalation phase I/II trial showed improvements in IIEF-15 assessment as well as increased vascularization of the corpora based on penile Doppler arterial velocity measurements. Although promising, further investigation in humans is required to substantiate BM-MNCs impact on erections, and erectile function recovery going forward.
Factors that mediate contraction in the penis include noradrenaline, endothelin-1, neuropeptide Y, prostanoids, angiotensin II, and others not yet identified. Factors that mediate relaxation include acetylcholine, nitric oxide (NO), vasoactive intestinal polypeptide, pituitary adenylyl cyclase–activating peptide, calcitonin gene–related peptide, adrenomedullin, adenosine triphosphate, and adenosine prostanoids.

I would think the 25% is just an average. Some men never have a problem with erections. Some healthy men in their 60's never have a problem with their erections -- no Viagra needed at all, thank you. And, no, it is NOT completely associated with age. In fact, many men in their 40's and even younger, are already dealing with ED, especially if they smoke, are obese, don't exercise, or are addicted to porn, among other things. In fact, even men in their 20's and 30's can have these problems.


Injection therapy involves injecting a substance into the penis to enhance blood flow and cause an erection. The Food and Drug Administration (FDA) approved a drug called alprostadil (Caverject) for this purpose in July of 1995. Alprostadil relaxes smooth muscle tissue to enhance blood flow into the penis. It must be injected shortly before intercourse. Another, similar drug that is sometimes used is papaverine—not yet been approved by the FDA for this use. Either drug may sometimes cause painful erections or priapism (uncomfortable, prolonged erections) that must be treated with a shot of epinephrine.
Talk with your doctor before trying supplements for ED. They can contain 10 or more ingredients and may complicate other health conditions. Asian ginseng and ginkgo biloba (seen here) are popular, but there isn't a lot of good research on their effectiveness. Some men find that taking a DHEA supplement improves their ability to have an erection. Unfortunately, the long-term safety of DHEA supplements is unknown. Most doctors do not recommend using it.
×