Measuring Testosterone Levels for Men

Measuring Testosterone Levels for Men

Men, have you ever had your testosterone levels checked?

Considering the media buzz about testosterone these days, many men wonder if they should.


We see news stories about testosterone replacement therapy and advertisements for testosterone boosting products that claim to make men feel young and virile again.

So it’s not surprising that men should have questions about testosterone testing. Today, let’s take a closer look. 

What is testosterone?

Before we start talking about the test, let’s go over what testosterone is.

Produced by the testes (testicles), testosterone is the male sex hormone. It gives a man his male characteristics, such as facial hair and a deeper voice. It’s also important for his sex drive, erections, and sperm production.

As a man gets older, his testosterone levels start to decline in a natural process called andropause. Some men compare andropause to female menopause, but men’s testosterone declines are less dramatic than women’s declines in estrogen. Around age 40, men’s testosterone levels start to decrease about 1% each year.

How is testosterone classified?

Testosterone is categorized as “bound” and “free.”

About 98% of a man’s testosterone travels through the bloodstream “bound” to proteins called albumin and sex hormone binding globulin (SHBG). Binding to these proteins makes it easier for testosterone to travel to where it is needed in the body.

The remaining testosterone is considered “free” because it is not bound to any substance.

“Total” testosterone measures bound and free testosterone together. When doctors check testosterone levels, they usually look at total testosterone readings, as these are considered the most reliable.

Why might a doctor order a testosterone test?

When a man shows signs of low testosterone (also called hypogonadism), a doctor may suggest testing. Symptoms of low testosterone include fatigue, mood changes, depression, decreased libido, erectile dysfunction, and muscle weakness.

Testing might be ordered for men with fertility problems, as testosterone plays an important role in sperm production.

Also, men with osteoporosis often have their levels checked.

What is the test like?

The test itself is a simple blood test. It is usually performed in the morning, between 8 am and 11 am, when testosterone levels are highest. (Most testosterone is produced during sleep.)

What do the results mean?

This is difficult to answer. Every man is different and what is considered normal for one man might be high or low for another.

Certain factors can affect the results of testosterone tests. For example, levels fluctuate during the day. They can also be influenced by a man’s blood sugar, triglyceride levels, and the medications he takes.

Testing protocols can also vary from lab to lab. The types of collection tubes used and the ways the samples are stored can affect the final measurements.

Generally speaking, levels of total testosterone below 300 ng/dL are considered “low.” Your healthcare provider can help you understand what your results mean for you as an individual.

Looking at the Whole Picture

If you believe you have low testosterone, see your doctor. Symptoms of low testosterone, such as low sex drive and tiredness, can have a number of different causes. Getting a thorough checkup with the doctor is the first step in pinpointing those causes so they can be treated effectively.

Above all, don’t try to diagnose yourself with low testosterone. Some men feel awkward discussing symptoms with their doctor and try to self-treat by using over-the-counter testosterone products. This is unwise. (Click here to learn more about the risks of these products.)


International Society for Sexual Medicine

“Standardization in Diagnosing Low Testosterone”



(Updated: March 22, 2012)

Renal and Urology News

Charnow, Jody A.

“Early AM Best for Measuring Testosterone in Younger Men with ED”

(February 17, 2014)

Sexual Medicine Society of North America

“Conditions – Low Testosterone”

“Free and Total Testosterone”

“Overview – Low Testosterone”

“Testosterone and Sleep”



(Last updated: May 17, 2012)