Causes of Low Testosterone in Men

Author: Brian Hildebrandt, Last Updated: Oct. 18, 2018

There can be many causes of low testosterone. Some are more direct as a result of common injuries.

Others not so obvious. Here’s a list of possible reasons your testosterone levels may be low.

Low Testosterone Causes

  1. Age
  2. Head Injury
  3. Testicular Injury
  4. Vasectomy
  5. Medication

Age and Low Male Testosterone

The older you get, the more susceptible you are to developing low testosterone. Organs eventually fail and wither, and your inner workings aren’t as efficient as they once were.

Average Testosterone Levels by Age in Men

AgeAverage Male Testosterone Level
15-24750 ng/dl
25-34700 ng/dl
35-44650 ng/dl
45-54600 ng/dl
55-64550 ng/dl
65-74500 ng/dl
75-84450 ng/dl
85-99400 ng/dl

Head Injury and Testosterone

If you’ve sustained a blow to the head or a traumatic brain injury, caused by a stroke, heart attack, or loss of oxygen for long periods of time, low testosterone may result.

An important part of the testosterone puzzle, called the HPTA (hypothalamic pituitary gonadal axis) may get damaged during such a injury.

The hypothalamus and pituitary gland are brain structures that act like traffic controllers to signal your testicles to make more testosterone. With those signals gone, there’s a good chance you may develop low testosterone levels.

Testosterone and Testicular Injury

Getting a traumatic injury to your testicles can also result in a cause of low testosterone. As part of the HPTA, your gonads (testicles) when damaged, will diminish or stop producing testosterone. So take care of those family jewels. Although you get a pair… two are better than one.

Vasectomies May Lower Testosterone

What your doctor may not have told you… a little known side effect of getting a vasectomy is developing an autoimmune (self-attacking) disorder, that literally kills your testicular tissue.

Since your sperm are no longer needed, your body attacks them like a foreign invader. Due to the closeness of your testicles to your sperm, they can suffer damage in the process.

Although this happens in a minority of people, it’s definitely important to keep a close eye on if any were to occur.

Causing Low Testosterone Through Injury

Medication may be the cause of low testosterone through three different paths. They can;

  1. Damage nerves
  2. Damage the vascular system
  3. Damage the endocrine system

Testosterone Lowering Medications/Drugs

  1. Anti-hypertensives (Inderal, Clonidine, Reserpine, Lasix, etc…)
  2. Antidepressants (SSRI’s, tricyclics, MAOi’s, etc…)
  3. Tranquilizers (Haldol, Thorazine, Zyprexa, Seroquel, etc…)
  4. Anticholinergics (Benadryl, Donnatal, Pro-Banthine, Cogentin, etc…)

If you’ve experienced any of these low testosterone causes, I’d suggest getting yourself checked by your doctor. Testosterone replacement may be needed if appropriate.


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