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
A study published in May 2014 in The Journal of Sexual Medicine found that some men can reverse erectile dysfunction with healthy lifestyle changes, such as exercise, weight loss, a varied diet, and good sleep. The Australian researchers also showed that even if erectile dysfunction medication is required, it's likely to be more effective if you implement these healthy lifestyle changes.
Alprostadil is a potent vasodilator and smooth muscle relaxant identical to the naturally occurring PGE1. PGE1 binds with specific receptors on smooth muscle cells and activates intracellular adenylate cyclase to produce cAMP, which in turn induces tissue relaxation through a second messenger system (96). PGE1 is the only FDA approved form of intracavernosal therapy and is available commercailly as EDEX, or Caverject. Its efficacy was demonstrated in several clinical trials where the rate of responders ranged from 40% to 80% (97,98). The most common adverse event is penile pain, which is not related to the injection of the medication itself. In men with prolonged use the pain is usually self-limited (99).
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.
Counselling and psychotherapy can help if one of the underlying causes of your erectile dysfunction is psychological. Counselling can also benefit men who have lost sexual confidence, even though their erectile dysfunction is caused by physical factors. Counselling may be provided by your doctor, a psychologist or a psychiatrist. Your partner may also be involved.
It is estimated that up to 20 million American men frequently suffer from impotence and that it strikes up to half of all men between the ages of 40 and 70. Doctors used to think that most cases of impotence were psychological in origin, but they now recognize that, at least in older men, physical causes may play a primary role in 60% or more of all cases. In men over the age of 60, the leading cause is atherosclerosis, or narrowing of the arteries, which can restrict the flow of blood to the penis. Injury or disease of the connective tissue, such as Peyronie's disease, may prevent the corpora cavernosa from completely expanding. Damage to the nerves of the penis, from certain types of surgery or neurological conditions, such as Parkinson's disease or multiple sclerosis, may also cause impotence. Men with diabetes are especially at risk for impotence because of their high risk of both atherosclerosis and a nerve disease called diabetic neuropathy.
The recommended starting dose of vardenafil is 10 mg taken orally approximately one hour before sexual activity. A doctor may adjust the dose higher or lower depending on efficacy and side effects. The maximum recommended dose is 20 mg, and the maximum recommended dosing frequency is no more than once per day. Patients can take vardenafil with or without food. As with sildenafil, for vardenafil to be effective, sexual stimulation must occur.
Alprostadil, a synthetic PGE1, is the most commonly used single drug for injections into the penis as a treatment for ED. It works well in the majority of men who try it. In one study of 683 men with ED, 94% reported having erections suitable for penetration after PGE1 injections. When PGE1 is used in combination with papaverine and Regitine, the mixture is called Trimix, which has roughly twice the effectiveness of alprostadil alone. However, Trimix is quite expensive and is usually not covered by insurance, while PGE1 is often a covered benefit in most insurance medication plans. The main side effects are pain from the medication (not from the injection), priapism (persistent or abnormally prolonged erection), and scarring at the site of the injection. It is recommended that one alternate the side of the penis being injected to help decrease the risk of penile scarring. Many men are uncomfortable with penile injection therapy even though the injection itself is painless. The injection cannot be done more often than every other day. Men on anticoagulant medications (blood thinners) must be careful with injection therapy.
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.
With sex therapy, your counselor looks at the sexual problems you and your partner are having. Sex therapy works with problems such as performance anxiety, which means that you worry so much about whether you will be able to have sex that you are not able to. It also helps when you have erection problems that are not due to physical or drug problems, or premature ejaculation (you come too quickly). It may help you to reach orgasm or to learn to relax enough to avoid pain during sex. Counseling can help you to adjust to the treatment you and your doctor choose.