free test vs. total test

[stevesmi]

some of the vets on here always say focus on free testosterone cause thats all that matters. but does that always apply or just while coming off a cycle on being on?

what is the difference between free and total in laymans terms?

is it possible for one to be in normal range and the other to be way out of range?

and what does it mean if one is out of range and the other is?

 

[chesty]

"What are free and bioavailable testosterone?

Testosterone is present in the blood as "free" testosterone (1-4%) or bound testosterone. The latter may be loosely bound to albumin, a serum protein, or bound to a specific binding protein called Sex Steroid Binding Globulin (SSBG) or Sex Hormone Binding Globulin (SHBG). The binding between testosterone and albumin is not very strong and is easily reversed; so the term bioavailable testosterone (BAT) refers to the sum of free testosterone plus albumin-bound testosterone. Alternatively, it is the fraction of circulating testosterone that is not bound to SHBG. It is suggested that BAT represents the fraction of circulating testosterone that readily enters cells and better reflects the bioactivity of testosterone than does the simple measurement of serum total testosterone. Also, varying levels of SHBG can result in inaccurate measurements of BAT. Decreased SHBG levels can be seen in obesity, hypothyroidism, androgen use, and nephritic syndrome. Increased levels are seen in cirrhosis, hyperthyroidism, and estrogen use. In these situations, measurement of free testosterone may be more useful. However, technically, free testosterone is difficult to measure accurately."

From a search on the subject.

 

[AFeedz]

I'm going to elaborate on what Chesty said.

There are two types of testosterone, like Chesty said. Bound testosterone and free testosterone.

For the sake of simplicity, I won't explain bound testosterone itself, but what you need to know about it is that because that type of testosterone is bound to something else, it is not active, meaning it's not really doing it's hormonal job.

Free testosterone, on the other hand, is bound to nothing and IS active. This means it's free for your body to use and is doing what you probably think of as testosterone's typical job because it is able to.

Basics:
Free Test = active.
Bound Test = inactive.

When you and others are measuring your test level, what you really want to know is your active test level, which is why your free (active) test is important. Reason being, a large part of your total test is doing nothing for you because the majority of your total test is made up of bound (inactive) testosterone.

It IS possible for one to be in range, while the other is not I suppose. When you measure total testosterone, you're measuring your free (active) test + your bound (inactive) testosterone.

Free Test + Bound Test = Total Test.

Typical total testosterone range is generally somewhere between 300-1000 ng/dL.

So because your free (active) test is included in your total test, the amount of it will be much smaller (as it should be). So I suppose you could have a small, but normal amount of free test, but your total test may be low due to your bound (inactive) test. In this case, your free test is in the range you want it to be, but you should still be concerned with your low bound test levels. It's not the test you're particularly concerned with, but your body (obviously) still has use for it.

Regardless, measuring your free test can be unreliable. You should also pay attention to your bio-available test.

Some of your bound test is bound to albumin, but can easily separate from it to become active. Bio-available test is the measure of free test + test attached to albumin.

Free Test + Test attached to albumin = Bio-Available Test

It can be useful because, like I said, what's important to you is how much testosterone is active in your body, and because testosterone attached to albumin can become active, Bio-available testosterone is also a measure of your active test level.

Like Chesty said though, both Bio-T and FT can be unreliable, but both measure active test, which is what you're concerned with so I would look at both. If your blood work results gave you your total testosterone, albumin, and SHBG levels, you can calculate both your FT and bio-T by yourself, no need for more tests.

Hope that helps.

 

[stevesmi]

i'm going to elaborate on what chesty said.

There are two types of testosterone, like chesty said. Bound testosterone and free testosterone.

For the sake of simplicity, i won't explain bound testosterone itself, but what you need to know about it is that because that type of testosterone is bound to something else, it is not active, meaning it's not really doing it's hormonal job.

Free testosterone, on the other hand, is bound to nothing and is active. This means it's free for your body to use and is doing what you probably think of as testosterone's typical job because it is able to.

Basics:
free test = active.
bound test = inactive.

when you and others are measuring your test level, what you really want to know is your active test level, which is why your free (active) test is important. Reason being, a large part of your total test is doing nothing for you because the majority of your total test is made up of bound (inactive) testosterone.

It is possible for one to be in range, while the other is not i suppose. When you measure total testosterone, you're measuring your free (active) test + your bound (inactive) testosterone.

free test + bound test = total test.

typical total testosterone range is generally somewhere between 300-1000 ng/dl.

So because your free (active) test is included in your total test, the amount of it will be much smaller (as it should be). So i suppose you could have a small, but normal amount of free test, but your total test may be low due to your bound (inactive) test. In this case, your free test is in the range you want it to be, but you should still be concerned with your low bound test levels. It's not the test you're particularly concerned with, but your body (obviously) still has use for it.

Regardless, measuring your free test can be unreliable. You should also pay attention to your bio-available test.

Some of your bound test is bound to albumin, but can easily separate from it to become active. Bio-available test is the measure of free test + test attached to albumin.

free test + test attached to albumin = bio-available test

it can be useful because, like i said, what's important to you is how much testosterone is active in your body, and because testosterone attached to albumin can become active, bio-available testosterone is also a measure of your active test level.

Like chesty said though, both bio-t and ft can be unreliable, but both measure active test, which is what you're concerned with so i would look at both. If your blood work results gave you your total testosterone, albumin, and shbg levels, you can calculate both your ft and bio-t by yourself, no need for more tests.

Hope that helps.

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