Health & Fitness

Free Testosterone Test – The Difference Between Free and Total T Levels

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People are becoming more and more eager to boost their testosterone levels. There are a number of benefits associated with this, but there are also a number of side effects associated with having too much testosterone in the body. The best way to figure out if you actually need to make a change is to get your free testosterone levels tested.

Free testosterone levels can be a bit confusing for those who are not sure what they are, so in this article, we’re going to teach you all about testosterone testing and explain the differences between free testosterone and total testosterone.

What is free testosterone?

Free testosterone is testosterone that is not attached to anything. It flows ‘freely’ through your blood.

Testosterone is a very important sex hormone that’s involved in a number of aspects of health. Testosterone is made in the testes and is responsible for many of the changes that young boys go through during puberty. Testosterone is involved in things like:

  • The growth of hair
  • The growth and maintenance of muscles
  • The health and maintenance of the sexual organs
  • The deepness of the voice
  • The intensity of a person’s sex drive, fertility, and sexual performance

Women also produce small amounts of testosterone in their ovaries, and while the hormone is still important for them, it’s not used as much in the female body as it is in males.

Free testosterone is also sometimes referred to as bioavailable testosterone, meaning it’s ready for your body to use for these different functions.

The difference between total and free testosterone levels

In most healthy men, the majority of testosterone is produced through the testes. The complex mechanisms behind this result in the conversion of cholesterol into testosterone. This testosterone is then secreted into the bloodstream, where they are bound to other molecules.

Much of the testosterone that’s found in your blood is attached to one of two proteins. The two proteins that it binds to are known as albumin and sex hormone binding globulin. Free testosterone is not bound to either of these proteins and is therefore referred to as free testosterone.

Testosterone that is only bound to albumin is also referred to as bioavailable testosterone as it’s much easier for your body to use than testosterone that has been bound to SHBF. Bioavailable testosterone is able to enter the body’s cells with ease, allowing the substance to act as a messenger or a signal to help your body maintain its metabolism and other important functions.

To evaluate whether or not you are actually at risk of testosterone deficiency or if you have some other hormonal issue, your doctor will look at these three ranges of testosterone:

  • free testosterone
  • bioavailable testosterone
  • total testosterone.


What is a free testosterone test?

A testosterone test, as you might have guessed, is a test that evaluates how much testosterone you have in your blood. A doctor will use the results of this test to figure out if any health problems that you’re struggling with have anything to do with low free testosterone.

Your doctor can learn a lot about the way that your body is producing and processing testosterone based on the ratios of the different levels of testosterone.

For example, if you have high levels of total testosterone but low free testosterone, this means that you might not need to actually increase the amount of testosterone that your body produces (which can be dangerous regardless). This indicates that your body might be producing more SHBG than necessary, and suggests that you will need to find a way to unbind the testosterone that you already have or figure out why you’re producing an excess amount of SHBG.

Free testosterone tests are most often given to males to help them figure out why they’re having sexual problems. They can identify the root cause of issues such as infertility or erectile dysfunction.

Females can also benefit from testosterone tests. They can help them to identify why they’re missing their menstrual cycle or having a hard time getting pregnant. Testosterone levels can also indicate polycystic ovary syndrome; a condition in which women may experience irregular periods and have a hard time getting pregnant.

When to take a testosterone test

Testosterone levels inside silhouettes

There is no set time to take a free testosterone test, though it can be useful to get them done every year or so to ensure that your body is producing enough of the hormone. However, there are a number of reasons that one might want to take a testosterone test. The main reason that people, especially men, take testosterone tests is to identify whether or not they have low levels of testosterone.

These are some of the most common symptoms of testosterone deficiency, so if you or your doctor notice any of the following, this may indicate the need for a testosterone test. It’s important to note that testosterone levels naturally decline with age, and in this case, treating with testosterone therapy is not recommended.

  • A decrease in sex drive, sexual performance or ability to maintain erection
  • Low energy, fatigue
  • Anemia
  • Difficulty concentrating, problems with mental functions like memory
  • Loss of muscle mass, gaining of fat
  • Infertility
  • Bone loss, decrease in mineral density on bones
  • Depression or mood instability

Testosterone tests can also be useful for women who may be experiencing high levels of testosterone. This can lead to conditions like polycystic ovary syndrome. A doctor may test you for high testosterone levels if any of the following symptoms are experienced:

  • Infertility, inability to get pregnant
  • Missed periods, irregular menstrual cycle
  • Acne
  • Obesity, sudden weight gain
  • Difficulty with blood sugar
  • Excessive hair growth on the face or body
  • Dark patches of skin
  • Hair loss
  • Enlarged clitoris

Some women may also require a testosterone test if they are experiencing very low levels of testosterone, though this is not commonplace. Symptoms of low testosterone in women include:

  • Decreased sex drive
  • Missed periods
  • Fertility issues
  • Dryness in the vagina
  • Weak bones, decreased bone mineral density


Free testosterone range for age groups (do you have low free testosterone?)

It can be helpful to know the normal, healthy levels of testosterone so that you can compare them to the results of your test. The following free testosterone ranges are measured in nanograms per deciliter, or ng/dL.


    • Between the ages of 19 and 49 – 249 to 836 ng/dL
    • Over 50 – 193 to 740 ng/dL


    • Between the ages of 19 and 49 – 8 to 48 ng/dL
    • Over 50 – 2 to 41 ng/dL

If there is any significant divergence from these numbers, it is likely that this is a factor in any health issues that you are experiencing.


Healthy free testosterone levels are important for helping to maintain many of the functions in the human body. A free testosterone test can help your doctor to understand whether or not your health issues are the result of a testosterone excess or deficiency.

If you are experiencing problems with fertility or sexual health, or if you’re worried that you have low testosterone levels, it could be worthwhile asking your doctor to test your testosterone levels.

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