erectile disfunction

Low Testosterone and Erectile Dysfunction

Low Testosterone and Erectile Dysfunction



Traditionally, low male hormone (testosterone) had been blamed as the main cause for erectile dysfunction (ED) and its supplement by injection was given some 3-5 decades ago.

Over time, the knowledge about low testosterone and ED has mounted and at this time, low testosterone is known only playing some role in inducing ED, which is always from multiple factors as described in What are the Causes for Erectile Dysfunction?. And the care for ED has evolved and changed as detailed in What are the Most Logical Steps to Treat Erectile Dysfunction?.

Thus far, how much do we know about low testosterone and ED? Some key and frequently asked points are listed as follows:

  • Causes: Primary – problem in testes; secondary – problem in the dysfunctioning regulation of hypothalamus to the pituitary gland to testes cycle; aging-related – also called andropause as opposed to menopause for women.
  • How often?: Some 80% of men could be affected over their lifetime or affecting some >4.5 million elderly American men; considered underestimated and underreported.

How to Diagnose Low Testosterone or Low-T or Andropause?

  1. professional awareness and alert at evaluating men with the following symptoms:
    1. frailty – decrease grip strength, diminished gait speed, easy fatigue and exhaustion, unintentional weight loss, low levels of physical activities;
    2. decreased energy, decreased mentation, a decrease in lean muscle mass and strength;
    3. decreased libido, erectile dysfunction, loss of morning erection, increased visceral fat;
    4. sleep disturbance, depression, metabolic syndrome (like diabetes, obesity, hypertension, high blood fat, etc.);
    5. Poor blood sugar control in diabetes mellitus;
    6. coronary or cardiovascular diseases.

2. physical exam:

    1. assess overall energy, muscle mass;
    2. assess clinical depression profile;
    3. check the size and consistency of testes and do the digital rectal exam (DRE) for the prostate.

3. Blood tests:

    1. Total testosterone (TT): done before 10 am; if <300ng/dl – meaningful for men with symptoms; if <200 ng/dl, meaningful for men without symptoms; but FDA reasearch trial defined low-T as <300 ng/dl.
    2. Free testosterone (Free-T): if <50 pg/ml, yes.
    3. Sex hormone binding globulin (SHBG): elevated as aging, resulting in a low biological active form of testosterone.
    4. Estradiol: increased conversion of testosterone to estradiol in fat tissue; so obesity leads to some decrease in testosterone.
    5. Blood sugar; PSA (prostate-specific antigen); liver function tests; blood count.


How may male testosterone change over the lifetime?

The following are what we know at this time:

  1. aging leads to a slow decrease in the number of Leydig cells (T-producing cells) in the testes.
  2. may decrease by 100 ng/dl (or 3.5 nmol/L from age 20-80 years.
  3. from 40-79 years, TT falls by 0.4 % a year and free-T, by 1.3 % a year.
  4. overall, it is reasonable to assume a slow decrease by 0.5-1 % per year after age 30.
  5. always correlate the lab findings with the clinical profile in a comprehensive evaluation.


What are the available options for testosterone supplements (TRT)?

  1. intramuscular: testosterone undecanoate, injectable…
  2. testosterone topical: Androgel 1%; Androgel 1.62% as Androderm, Axiron, Fortesta, Striant, Testim, VagelXO.
  3. Nasal topical use: Natesto.
  4. testosterone implant: Testopel.

Precautions on TRT

  1. avoid a contact with children;
  2. watch for adverse side effects especially for the injectable form;
  3. follow the advice from the prescribing doctor with close follow-up for possible efficacy, repeating blood testing for red blood cells, and liver function tests.

How to Treat Andropause (aging-related low-T)?

First line: TRT (testosterone replacement therapy):

  1. intramuscular, transdermal (through the skin, with patches or gels); this should be decided by the doctor and patient together.
  2. TRT should be individualized;
  3. Absolute contraindications: a history of breast cancer or untreated prostate cancer.
  4. Relative contraindications: polycythemia (high red blood cell count), BPH with voiding symptoms so to watch for urinary retention, treated prostate cancer.


What are the common associated medical conditions?

They may include metabolic syndrome, diabetes mellitus, hypertension, tobacco abuse, sleep apnea, psychological disorders, and social stress.


What do you expect to experience from TRT?

If effective, the patients may feel some improvement in the quality of life, mood and affect, sexual function and libido, cognitive function, and blood sugar control.


How are the complementary or alternative treatments?

  1. stress increased weight-bearing exercise, dieting and general exercise, weight loss, etc.
  2. Phytotherapies (herbal): The research on their efficacy and safety is quite limited; the data on the ability of any OTC supplements to influence T-level is limited.

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