If you can't take one of these oral medications, your physician may have you try Caverject (alprostadil for injection), a hormone that you inject into your penis using a fine needle, or Muse (alprostadil urogenital), a tiny suppository that you insert into the tip of the penis. Both of these will bring on an erection within five to 15 minutes without sexual stimulation.
In diabetes, vasoconstrictors and vasoactive factors are increased in addition to structural changes and attenuation of relaxation responses in the corpus cavernosum. A shifting of the balance of vasoactive factors occurs such that relaxation factors (eg, nitric oxide [NO]) are inhibited and contractile factors are induced in microvascular disease. With epidemiological predictions suggesting that the incidence of diabetes mellitus will increase to 300 million by 2025, management of diabetes-induced ED is increasingly important.
Arginine. The amino acid L-arginine, which occurs naturally in food, boosts the body's production of nitric oxide, a compound that facilitates erections by dilating blood vessels in the penis. Studies examining L-arginine's effectiveness against impotence have yielded mixed results. A 1999 trial published in the online journal BJU International found that high doses of L-arginine can help improve sexual function, but only in men with abnormal nitric oxide metabolism, such as that associated with cardiovascular disease. In another study, published in 2003 in the Journal of Sex & Marital Therapy, Bulgarian scientists reported that ED sufferers who took L-arginine along with the pine extract pycnogenol saw major improvements in sexual function with no side effects. Arginine can be helpful, says Geo Espinosa, ND, director of the Integrative Urological Center at NYU Langone Medical Center. Espinosa says that men with known cardiovascular problems should take it only with a doctor's supervision; L-arginine can interact with some medications.
It doesn’t look good for the herbs. So far, there’s no data from controlled human trials that support the erection-promoting claims for any 5 of the most frequently used herbs. The icariin in the horny goat weed can help get it up, but since you’re getting the herb rather than a purified molecule, the concentration probably isn’t high enough to have much of an effect. Worse, it turns out that Viagra is much better at blocking that erection-killing enzyme than icariin is.
Prescription drugs called “oral phosphodiesterase-5 (PDE5) inhibitors” are considered the “first-line non-invasive treatment” options for patients with ED. These include the drugs that go by brand names: Sildenafil, Vardenafil or Tadalafil. They work by helping the smooth muscle cells lining the blood vessels that supply the penis with blood to work properly. This allows a man to maintain an erection more easily.
The Plant: A low-growing flowering annual that’s originally from southern Europe but is now an invasive weed in parts of the United States and Australia. The plant’s common names, like puncturevine or devil’s thorns, tells you exactly why most people hate it: it drops sharp, spiny seed pods that lie in wait for unsuspecting victims to step on them. It’s also toxic to grazing livestock like sheep.
However, you might actually be better off going one step back in the chain reaction and taking an L-citrulline supplement. While your body converts L-arginine to nitric oxide, it also metabolizes it too fast when the amino acid is taken in an oral supplement, according to a 2011 study from the University of Foggia in Italy. L-citrulline, which the body converts to L-arginine, is actually a better option to follow the same metabolic pathway and serve as a treatment for ED, the same study found.
E longifolia is a medicinal plant (family Simaroubaceae) native to Indonesia, Malaysia, Thailand, Vietnam and Laos. The root extract has been found to be the most powerful herbal aphrodisiac . Tongkat ali extracts contain many alkaloids, quassinoids, phenolic compounds, tannins, high-molecular-weight glycoproteins and mucopolysaccharides. The main bioactive compounds are eurycomaoside, eurycolactone, eurycomalactone, eurycomanone and pasakbumin-B. It is considered to be natural ‘Viagra’. It increases sexual desire, and enhances performance and general well-being [17- 19]. In addition to its aphrodisiac effect, other medicinal effects, such as antimalarial, antibacterial, antipyretic, antiulcer and antitumour effects, have been reported [20,21]. Root decoction has been used as a general tonic (18,22]. Laboratory animal studies show that root extract enhances sexual characteristics and performance in rodents [22-25]. In a study involving a boar model, it was found that E longifolia root extract-treated boars increased sperm counts and semen volume; the effect was attributed to increased level of plasma testosterone . Reports also suggest that E longifolia extract reverses the inhibitory effects of estrogen on testosterone production and spermatogenesis in rats . Oral administration of E longifolia extract to inexperienced castrated male rats produced dose-dependent increases in sexual performance . Zakaria et al  found that eurycomanone, a potential bioactive compound in the root extract of E longifolia, induced apoptosis in hepatocarcinoma (Hep G2) cells. Furthermore, their work suggested that eurycomanone was cytotoxic to Hep G2 cells and less toxic to normal Chang’s liver and WLR-68 cells. Tambi and Imran  investigated the effects of water-soluble extract of the root of E longifolia Jack and found that the extract increased semen volume, sperm concentration, percent of normal sperm morphology and sperm motility in male partners of subfertile couples with idiopathic infertility. Supplementation with E longifolia elevated the testosterone levels and upregulated osteoprotegerin gene expression in male Sprague-Dawley rats .
Ginkgo biloba. Known primarily as a treatment for cognitive decline, ginkgo has also been used to treat erectile dysfunction -- especially cases caused by the use of certain antidepressant medications. But the evidence isn't very convincing. One 1998 study published in the Journal of Sex & Marital Therapy found that it did work. But a more rigorous study, published in Human Pharmacology in 2002, failed to replicate this finding. "Ginkgo has come out of fashion in the past few years," says Ronald Tamler, MD, assistant professor of medicine and codirector of the men's health program at Mount Sinai Medical Center in New York City. "That's because it doesn't do much. I can say that in my practice, I have not seen ginkgo work -- ever."
Ginseng. Korean red ginseng has long been used to stimulate male sexual function, but few studies have tried systematically to confirm its benefits. In one 2002 study involving 45 men with significant ED, the herb helped alleviate symptoms of erectile dysfunction and brought "enhanced penile tip rigidity." Experts aren't sure how ginseng might work, though it's thought to promote nitric oxide synthesis. "I would recommend ginseng [for men with ED]," says Espinosa. Discuss with your doctor before taking it since ginseng can interact with drugs you may already be taking and cause allergic reactions.
There are so many potential reasons a man might develop erectile dysfunction (ED), it's nearly impossible to generalize the best ways to treat it. What works for one man may not work for another simply because they are having problems for different reasons. That said, it may encouraging to hear that there are a variety of options that may be considered, from psychological counseling to lifestyle changes, medications to treatments and devices.
Tongkat Ali (Eurycoma longiflora) (Figure 7): this native plant found through SE Asia is used as an Aphrodisiac since 1996 (5). It has to be used regularly and works by enhancing the testosterone and cGMP production. Benefits are felt gradually over a period of time, mainly because it enhances the natural biological synthesis of testosterone. When the level is increased, health and vitality are restored. In studies on Mice, Tongkat Ali increases the number of times and duration of sexual performance of the animals under study (8) with testosterone levels increasing up to 440% in some animals. In a recent study on humans, 62% of subjects showed an increase of the free testosterone index indicating it’s biostimulatory effect on steroidogenesis. It has also been shown to increase sperm concentration and motility and increases energy in the individual by enhancing ATP production by 60% thru oxidative phosphorylation.
Shape up. Because ED is often linked with restricted blood flow to the penis, keep your heart and arteries in good condition by maintaining a healthy weight, and following a diet high in fruits, vegetables and whole grains. Avoid saturated fats and trans fats. Regular aerobic exercise can improve blood flow to the genitals and reduce any stress that contributes to your ED.