Free testosterone as a guage

[jaydee]

I get really confused with this subject. Some endo's claim that free T is important and some dont. Does anyone know what the real deal is with this?

My Total T is about mid range but my free T is well below range. Also my Free Androgen Index is about midrange. What does this mean? My DHT is low - just in range and my doctor has said that i need to go on a testosterone gel.

My SHBG and E is in check BTW.

Also is Free Androgen Index the same as Bioavailable Testosterone?

 

[jjohn]

I get really confused with this subject. Some endo's claim that free T is important and some dont. Does anyone know what the real deal is with this?

My Total T is about mid range but my free T is well below range. What does this mean? My DHT is low - just in range and my doctor has said that i need to go on a testosterone gel.

My SHBG and E is in check BTW. And i have low DHT but just within range.

Free test, if I am right, is what can be used by your body, so if it's below range, you could benefit from a test. get IMO.

 

[12gauge]

What about when someone has low total T, 300 - 400 range, low shbg, 15, but mid level bioavailable T, 140, range 40-250? This seems to be a common thing with small skinny guys who arent aging much, low SHBG.

there has been discussion with marianco & meso group about SHBG being low affecting the ability of T to unbind & be used when needed or something. SHBG seems to be a misunderstood & undervalued item to watch in my opinion.

curiuos as to Dr Johns thoughts on low SHBG.

Free T is indeed important. Total T can be well within normal range, but the actual amount that presents to the receptor, the "Bioavailable Testosterone" can be MUCH lower, even below range.

As we age, due to increasing SHBG levels, the spread between Total T and Free T increases. Therefore even if Total T stays the same, Free T can drop substantially.

Free T has its limitations. It is measured in picograms, a unit so small it makes things diffcult. Free T is not stable in the sample, as well. But it is a very useful assay for us nonetheless. Gold standard, without a doubt, is Bioavailable T.

No doctor who understands hormones would claim the Free T assay is not "important". Unless, of course, it is in deference to the Bio T.

 

[12gauge]

thanks for your reply, i will have to watch for special flight discounts to your area to come see you.

It's not a matter of some sort of issue with differential "unbinding". It just means a greater proportion of the total sex hormones--androgens AND estrogens--are available.

That is why Bioavailable T AND Bioavailable E assays are the gold standard--you needn't worry about the rest.

A problem is that with low SHBG you can have a lot of E floating around.

I am now using clomid to elevate SHBG in these fairly rare individuals. It's MUCH more common to see high-normal SHBG.

There is a differential in the affinity of androgens and estrogens, with SHBG preferring androgens, with a spread approaching 10%. Therefore, the higher SHBG level is, more AND MORE estrogen is floating around compared to androgen. This increased estrogen/androgen ratio does have deleterious effects. How that all works at the other end of the SHBG range is a bit trickier.

It looks like there is a range of affinities for SHBG to the sex hormones amongst individuals.

Either way, as time goes on, I become more and more aware of the effects of SHBG levels.

"SHBG seems to be a misunderstood & undervalued item to watch in my opinion.". Well said!

 

[spinn]

If anyone doesnt know difference between free and bioavailable....like I didnt until a few minutes ago.....

"4. What are free and bioavailable testosterone? Testosterone is present in the blood as "free" testosterone (2-3%) or bound testosterone. The latter may be bound to either albumin (a serum protein) or to a specific binding protein called Sex Steroid Binding Globulin (SSBG) or Sex Hormone Binding Globulin (SHBG). The binding of testosterone to albumin is not very tight 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 SSBG. 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 SSBG can result in inaccurate measurements of BAT. Decreased SSBG 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."

Testosterone: Common Questions

 

[somewhatgifted]

Activate by anabolic extreme is a great free test booster. Good info thanks for the read.

 

[jaydee]

Thanks for all your replys..

Does anyone know if Free Androgen Index is the same thing as Bioavailable Testosterone?