Low Testosterone (Low-T)

Medical Author:
Medical Editor:

Low testosterone (Low-T) definition

Testosterone is a hormone required for male development and is produced primarily in the testicles. It is responsible for building muscle and bone mass as well as sperm production and sex drive. It influences male pattern fat distribution, bone density, and red blood cell production.

Lack of or underproduction of testosterone either directly due to decreased production in the testes or indirectly due to lack of stimulation of the testes to produce testosterone by the pituitary gland is called hypogonadism and is a medical condition requiring treatment.

In the normal developing male, testosterone peaks during early adulthood. Once you reach age 30, testosterone levels slowly decline by approximately 1% a year. This is a normal part of aging.

What are the normal levels of testosterone in men?

The low limit of testosterone levels in men is about 300 nanograms per deciliter and the upper normal limit is approximately 1000-1200 ng/dl. A low level needs to be investigated further to distinguish it from normal aging.

What causes low testosterone (Low-T)

Some of the conditions that can lead to a low level are:

  • Obesity
  • Diabetes (type 2)
  • Chronic medical conditions (especially liver or kidney disease)
  • Hormonal disorders
  • Infections
Medically Reviewed by a Doctor on 1/22/2015

Patient Comments

Viewers share their comments

Low Testosterone (Low T) - Causes Question: What caused your testosterone levels to decrease?
Low Testosterone (Low T) - Symptoms Question: What symptoms did you experience when your testosterone levels dropped?
Low Testosterone (Low T) - Experience Question: Please describe your experience with low-T.
Low Testosterone (Low T) - Treatment Question: How was your case of low testosterone treated?
Low Testosterone (Low T) - Diagnosis Question: Describe the events that led to the testing and diagnosis of low testosterone.

Low Libido (Low Sex Drive) Symptoms

A decrease in sex drive can develop both due to medical conditions as well as to psychological or emotional issues. Inhibited sexual desire is a type of sexual dysfunction that affects both men and women.

  • A reduction in sexual desire has been associated with low levels of testosterone in men.
  • Women in the menopausal transitions sometimes report a decrease in sex drive.