Reiter, W. J., Pycha, A., Schatzl, G., Pokorny, A., Gruber, D. M., Huber, J. C., & Marberger, M. (1999, March). Dehydroepiandrostone in the treatment of erectile dysfunction: A prospective, double-blind, randomized, placebo-controlled study [Abstract]. Urology, 53(3), 590-594. Retrieved from http://www.sciencedirect.com/science/article/pii/S0090429598005718
Classically the neuro-physiology of ejaculation traces the 3 Phases in which ejaculation is a complex event involving the (I) the propulsion of sperm and seminal plasma into the prostatic urethra which is accompanied by (II) bladder neck closure and (III) coordinated contractions of the bulbocavernosus and ischiocavernosus muscles, striated muscles of the pelvic floor, lower limbs and trunk. In the Asian Society of the Aging Male Study  63% have reduced erection, 68% reduced or absent ejaculation and 19% pain or discomfort at ejaculation. Disorders of ejaculation can be due to: (I) disorders of production of sperm or seminal plasma/prostatic secretions (II) disorders of propulsion. In the case of anejaculation (absence of ejaculatory) which is the ultimate disorder of ejaculation, the causes can be best classified as (I) primary or secondary. After covering psychogenic causes of ejaculation failure, the organic causes due to non-dynamic and obstructive etiologies in the prepubertal and post pubertal male will be highlighted. More details will be given on retarded ejaculation, premature ejaculation, aspermia, painful and weak (poor propulsive force) ejaculation. The evaluation of the patient must include a detailed history taken from the patient and often his partner. Aside from haematologic tests, various forms of radiological and ultrasonic imaging, neurophysiologic studies may be required. For the general practitioner the commonest scenario will be in the ED Clinic with abundant men with performance anxiety presenting with premature ejaculation. In the male aging clinic lack of arousal is the commonest cause of retarded orgasm and ejaculation but this group is plagued by decreased touch sensitivity, the need for more direct stimulation, reduced drive to orgasm, a less intense orgasm, ejaculation being weaker and of reduced quantity and disturbing complaints of a longer recovery period and less number of attainable orgasms per day or week. Thus it is not mere rumor that “by the time a man reaches 55, the refractory period to ‘do it again for a man’ increases to 12 hours or even up to a week”. In the STD clinic, painful or bloody ejaculation is frequently seen. The Condom may cause condom retarded orgasm/ejaculation.
If you bike a lot and have a very narrow saddle on your bicycle, consider switching to a "no-nose seat" which is wider at the back than a conventional saddle, allowing more of your weight to be distributed to the sitting bones. Make sure the seat is level or angled slightly downward and at a height that allows your knee to be just slightly bent at the bottom of the pedal cycle. Raising the handlebars on your bike so that you're sitting upright may also help.
It is commercially available as soft gels and tablets. For treatment of male infertility and erectile dysfunction, dosage of 30-300 milligrams taken by mouth, once daily or in divided doses for up to 26 weeks is recommended by experts. The dose can be taken for up to 6 months. It has shown to be effective in treating erectile dysfunction among men.
Just because a product claims to be natural doesn't mean it's safe. Many herbal remedies and dietary supplements can cause side effects and dangerous interactions when taken with certain medications. Talk to your doctor before you try an alternative treatment for erectile dysfunction — especially if you're taking medications or you have a chronic health problem such as heart disease or diabetes.