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How Low Testosterone Affects Erectile Dysfunction

Erectile dysfunction refers to a man’s inability to develop or maintain an erection of the penis.

The World Health Organization defines erectile dysfunction as have the following characteristics:

  1. Persistent – 3 months or more
  2.  Inability to attain an erection or maintain an erection
  3. Unsatisfactory sexual intercourse


The prevalence (total current cases) of erectile dysfunction is unclear because of the various definitions used for this illness and the different ways that studies are designed to determine prevalence.  The prevalence varies greatly from 10 to 52% of men, with most of the studies focusing on men ages 40 – 70 years of age.  In western countries, studies indicate that the incidence (new cases) of erectile dysfunction is from 25 to 30 new cases per 1000 people per year.  The majority of the men with erectile dysfunction are untreated.

Causes of Erectile Dysfunction

Erectile dysfunction may be caused by psychological or physical problems.  Psychological causes – such as depression – or other feelings and thoughts can prevent a person from being aroused mentally.  These can sometimes be treated with appropriate psychological therapy.  The physical causes vary and are often more difficult to treat.  Among these causes are hormonal insufficiencies (hypogonadism), diabetes, cardiovascular diseases, neurological diseases (i.e. multiple sclerosis and spinal cord injuries),

hormonal dysregulation (i.e. elevated prolactin and Cushing syndrome) smoking, drug use, excessive alcohol consumption, and drug side effects. 

These causes are more common in older men, which increase the prevalence of erectile dysfunction in men who are over 60 years of age.

Role of Testosterone

Testosterone is also well known for its role in the normal development of penile tissue and early male sexual characteristics during puberty, including penis growth.  However, a low level of testosterone is also one of the factors which can lead to erectile dysfunction.  Erections arise from two mechanisms: reflex or emotional stimuli.  Both involve a fairly complex set of events which are regulated to some degree by testosterone.  Adequate levels of testosterone are required for a healthy erectile system.  Testosterone appears to synchronize the erection process by stimulating the production of nitric oxide at the beginning of the erection and also stimulating the production of PDE-5 which leads to the end of an erection.  One study show that America’s increasing obesity problem is also connected to testosterone.  Men who are obese have lower levels of testosterone resulting in hypogonadism and increasing their chances of erectile dysfunction.
Some studies indicate that it determines the frequency of night time erections or near erections and also have morphine like effect on the brain (the sense of an orgasm).  As testosterone declines normally with age, the frequency of erections decreases further demonstrate the role of testosterone in the erection process.  One study demonstrated that lower levels of testosterone results in impaired relaxations of muscles of the penis which means a decreased chance of having an erection.  Hence, erections are clearly dependent on normal levels of testosterone.

Testosterone Therapy as Treatment for Erectile Dysfunction

The use of testosterone therapy to treat erectile dysfunction also supports the role of low testosterone as a risk factor for erectile dysfunction.  One recent study demonstrated that with testosterone therapy night time near erections, penile blood flow and visually stimulated erections increase.  Testosterone therapy was supported by an article which examined a number of past studies (meta-analysis).  This meta-analysis which was conducted in 2000 revealed that studies between 1966-1998 demonstrated a statistically significant greater response to testosterone therapy for erectile dysfunction in the treatment groups versus control groups. Treatment with testosterone is viewed as more permanent than other treatments because it addresses an underlying cause, hormonal deficiency, which is easier to adjust than other physical causes of erectile dysfunction.  The goal of this treatment is to provide a dosage of testosterone that mimics the normal level of testosterone and its related metabolites in the man’s body.  This goal can be met with different, existing testosterone therapies which include patches, gels, and long acting injections.  Testosterone can also be used in conjunction with a PDE-5 inhibitor.  As stated earlier, PDE-5 is a combined which increases in order to stop an erection. The PDE-5 inhibitor prevents this compound from acting and thereby leads to a longer erection.  However, some men do not respond to this drug and testosterone can provide added benefits to these men.

If you are interested in learning more on erectile dysfunction or any other sexual health related problems, contact one our clinics today.

M Diaz-Arjonilla1, M Schwarcz1, RS Swerdloff and C Wang. Obesity, low testosterone levels and erectile dysfunction. International Journal of Impotence Research (2009) 21, 89–98

Jain P, Rademaker AW, McVary KT. Testosterone supplementation for erectile dysfunction: results of a meta-analysis. J Urol 2000; 164: 371–5

Lunenfeld B, Saad F, Hoesl CE. ISA, ISSAM and EAU recommendations for the investigation, treatment and monitoring of late-onset hypogonadism in males: scientific background and rationale. Aging Male 2005; 8: 59–74.

Kubin M, Wagner G, Fugl-Meyer AR. Epidemiology of erectile dysfunction. Int J Impot Res. 2003 Feb;15(1):63-71.

Farid Saad, Anca S. Grahl , Antonio Aversa, Aksam A. Yassin, Atez Kadioglu, Ignacio Moncada and Ian Eardley. Effects of testosterone on erectile function: implications for the therapy of erectile dysfunction. 2 0 07 B J U I N T E R N A T I O N A L | 9 9 , 9 8 8 – 9 9 2