But don’t panic. ED can be caused by a number of factors, from depression and medication side effects to high blood pressure, high cholesterol, low testosterone levels, Peyronie’s disease, nerve damage, performance anxiety, heart disease, diabetes, and more. Even better, many of these ED causes are treatable with medication and simple lifestyle changes. It’s important to know the root cause of your erectile dysfunction in order to treat it in the fastest, most effective way possible. Here are the 5 most common causes of erectile dysfunction.

Booze. Most men have learned: One too many cocktails doesn’t improve performance; instead, it can have the opposite effect. During a recent study of 1,506 Chinese males, the men who drank three or more drinks a week were more likely to have ED or some form of sexual dysfunction. “Men may find that alcohol decreases social inhibition, which makes it easier to approach a woman,” says Montague. “But alcohol is a depressant, and at higher quantities it can reduce both a man’s desire and ability to perform.”


L-arginine is an amino acid that occurs naturally in the human body and helps make that magic nitric oxide so important for supporting an erection. A 1999 study observed the effects of six weeks of L-arginine administered daily among men with ED. One third of those who took five grams per day of L-arginine experienced significant improvements in sexual function.
Other hormone levels: Measurement of other hormones beside testosterone (luteinizing hormone [LH], prolactin level, and cortisol level) may provide clues to other underlying causes of testosterone deficiency and erectile problems, such as pituitary disease or adrenal gland abnormalities. Doctors may check thyroid levels in some individuals as both hypothyroidism (low thyroid function) and hyperthyroidism (overactive thyroid function) can contribute to erectile dysfunction.
In many of these cases, a discussion between the physician, the man with erectile dysfunction, and possibly his partner can help to resolve the issues leading to treatment failure. For men who experience severe side effects, can’t take the drugs for other reasons (such as taking medicines such as nitroglycerin), or don’t respond in spite of further education on the correct use of the drugs, there are other treatment options that can help most men remain sexually active.
PDE 5 inhibitors are broken down primarily by enzyme, cytochrome P450enzyme CYP3A4. Medications that decrease or increase the activity of CYP3A4 may affect levels and effectiveness of PDE 5 inhibitors. Such drugs include medications for the treatment of HIV (protease inhibitors) and the antifungal medications ketoconazole and itraconazole. Thus caution is recommended.
ED may occur with or without other sexual dysfunction, including decreased libido (decreased interest in sexual activity), orgasmic dysfunction (troubles achieving an orgasm/climax), and ejaculatory dysfunction (problems with the fluid released during sex, including lack of ejaculation [anejaculation], small volume ejaculate, ejaculation that occurs too quickly [premature ejaculation], ejaculate that goes backward into the bladder [retrograde ejaculation] and pain with ejaculation).
There is no evidence that mild or even moderate alcohol consumption is bad for erectile function, says Ira Sharlip, MD, a urology professor at the University of California San Francisco School of Medicine. But chronic heavy drinking can cause liver damage, nerve damage, and other conditions -- such as interfering with the normal balance of male sex hormone levels -- that can lead to ED.
The condition is often an early warning sign of heart disease and other circulatory problems. To achieve and maintain an erection, extra blood must be able to flow unimpeded. Anything that interferes with healthy flow – for example atherosclerosis, the artery-clogging process at the root of most heart attacks, strokes, and other cardiovascular conditions – has the potential to cause erectile dysfunction, too.
Occasional ED is common in all men, including young and healthy men. But if you have a persistent or recurrent problem with initiating or maintaining an erection and it's causing you or your partner distress, talk to your doctor. “Lack of nighttime erections is another cause for concern, said Wang. These occurrences serve to nourish the penis with oxygen and keeping the blood supply healthy, he explained. "Young men should get four or five of these a night. If you are not getting these and you are having frequent problems with ED, you need to check in with your doctor,” he recommended.

When a man becomes sexually excited, muscles in their penis relax. This relaxation allows for increased blood flow through the penile arteries. This blood fills two chambers inside the penis called the corpora cavernosa. As the chambers fill with blood, the penis grows rigid. Erection ends when the muscles contract and the accumulated blood can flow out through the penile veins.
Treatments include psychotherapy, adopting a healthy lifestyle, oral phosphodiesterase type V (PDE5) inhibitors (Viagra, Levitra, Cialis, Stendra, and Staxyn), intraurethral prostaglandin E1 (MUSE), intracavernosal injections (prostaglandin E1 [Caverject, Edex], Bimix and Trimix), vacuum devices, penile prosthesis and vascular surgery, and (in some cases) changes in medications when appropriate.
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.
If you have symptoms of ED, it’s important to check with your doctor before trying any treatments on your own. This is because ED can be a sign of other health problems. For instance, heart disease or high cholesterol could cause ED symptoms. With a diagnosis, your doctor could recommend a number of steps that would likely improve both your heart health and your ED. These steps include lowering your cholesterol, reducing your weight, or taking medications to unclog your blood vessels.

Erectile dysfunction: Dehydration causes decreased blood volume and increased angiotensin, a hormone associated with erectile dysfunction. Long-term alcohol abuse can cause damage to the nervous system, which is responsible for triggering the signals that cause an erection. Studies have also shown that prolonged abuse can cause irreversible damage to the nerves in the penis. Additional studies have shown erectile dysfunction is present in alcohol abusers even when they are sober.
Before taking any medication for erectile dysfunction, including over-the-counter supplements and herbal remedies, get your doctor's OK. Medications for erectile dysfunction do not work in all men and might be less effective in certain conditions, such as after prostate surgery or if you have diabetes. Some medications might also be dangerous if you:
Penile implants: This treatment involves permanent implantation of flexible rods or similar devices into the penis. Simple versions have the disadvantage of giving the user a permanent erection. The latest (and most expensive) device consists of inflatable rods activated by a tiny pump and switch in the scrotum. Squeezing the scrotum stiffens the penis, whether the person is aroused or not. The penis itself remains flaccid, however, so the diameter and length are usually less than a natural erection, and hardness is lacking, although it's sufficient for intercourse.

In the popular media, it’s easy to find claims of a rising “epidemic” of erectile dysfunction in young men. For example, this article argues that the rate of ED in young men has increased 1000% in the last decade alone—though, problematically, no research is cited to back it up, which makes this a very questionable claim. So what does the science say on this subject? Are erectile difficulties really rising at a dramatic rate in young guys? Let’s take a look.


This category of treatments includes external vacuum therapies: devices that go around the penis and produce erections by increasing the flow of blood in, while constricting the flow out. Such devices imitate a natural erection, and do not interfere with orgasm. External vacuum therapy mechanisms are approximately 95 percent successful in causing and sustaining an erection. All are portable, and costs range between $200-$500, covered under most insurance plans and Medicare Part B.
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