halfwit
I like turtles.
Total is indicative of overall HPTA health while free is what does the work. Bioavailable and free T are the same thing by the way.
got my test levels checked
- Thread starter profboy
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Total is indicative of overall HPTA health while free is what does the work. Bioavailable and free T are the same thing by the way.
halfwit
I like turtles.
Megatron28
Moderator
Total is indicative of overall HPTA health while free is what does the work. Bioavailable and free T are the same thing by the way.
Yes... feeling much better.
Actually, Free-T and Bioavailable T technically are not the same thing.
Most circulating testosterone is bound to sex hormone-binding globulin (SHBG), which in men also is called testosterone-binding globulin. A lesser fraction is albumin bound and a small proportion exists as free hormone. Historically, only the free testosterone was thought to be the biologically active component. However, testosterone is weakly bound to serum albumin and dissociates freely in the capillary bed, thereby becoming readily available for tissue uptake. All non-SHBG-bound testosterone is therefore considered bioavailable.
halfwit
I like turtles.
See now that is interesting as Quest diagnostics and a couple other medical facilities treat it the same with regards to ordering tests. I know some list it separately, but the same value is given for both FT and BT. SHBG-bound and unbound T would be total, whereas the unbound hormone would be free. You kind of left the emphasis off the part:
You stinker.
Source
As Free test is unbound, and all unbound testosterone is bioavailable, free test therefore equals bioavailable.
Quot Erat Demonstratum.
Megatron28
Moderator
See now that is interesting as Quest diagnostics and a couple other medical facilities treat it the same with regards to ordering tests. I know some list it separately, but the same value is given for both FT and BT. SHBG-bound and unbound T would be total, whereas the unbound hormone would be free. You kind of left the emphasis off the part:
You stinker.
Source
As Free test is unbound, and all unbound testosterone is bioavailable, free test therefore equals bioavailable.
Quot Erat Demonstratum.
Ha! You found my source.
The difference is the T bound to Albumin. Albumin bound T is not Free, but it is Bioavailable. Therefore they are no equal. At least that is how I read this. Am I missing something? Maybe if someone drew up a Venn Diagram that would help.
halfwit
I like turtles.
Ha! You found my source.
The difference is the T bound to Albumin. Albumin bound T is not Free, but it is Bioavailable. Therefore they are no equal. At least that is how I read this. Am I missing something? Maybe if someone drew up a Venn Diagram that would help.
Except the testosterone not bound to SHBG is considered "free", even though it is technically bound to a protein in blood plasma (Albumin).
You ask and you shall receive!
Edit: Technically all the "free" testosterone on the right side is also bio-available testosterone too. I know, it's confusing as hell.
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Megatron28
Moderator
But the Test bound to Albumin is not considered to be Free. You keep saying non-SHBG bound test is free. But by definition it isn't free. It is just bioavailable. It is probably soon to be free, but just not at the moment the lab test was performed.
Megatron28
Moderator
Here's what I am reading. Test can be found in three states.
Bound to SHBG
Bound to Albumin
Not Bound to anything (Free)
Free Test is only the last category which is not bound to anything.
Bioavailable is Free Test + Albumin Bound Test.
Bound to SHBG
Bound to Albumin
Not Bound to anything (Free)
Free Test is only the last category which is not bound to anything.
Bioavailable is Free Test + Albumin Bound Test.
halfwit
I like turtles.
Except that testosterone not bound to SHBG is called free. I don't make the rules or naming conventions silly. When I actually wake up, I'll have to find a good source for you.
Megatron28
Moderator
Except that testosterone not bound to SHBG is called free. I don't make the rules or naming conventions silly. When I actually wake up, I'll have to find a good source for you.
Why have different names if they are the same thing?
halfwit
I like turtles.
Since when does the medical community make sense? Damn, this omelette is gooooooood.
Edit: Ya know what Mega, I'm actually starting to get confused here. I keep reading studies and clinical trials that identify ONLY free versus total testosterone; with a footnote about albumin bound in the free, while others cite that free/albumin-bound are bio avail, but that free itself is a subcategory of albumin-bound as it is truly free, and not bound to any proteins.
I think I stand by my statement above in that the medical community makes absolutely no sense sometimes.
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Spunkey71
New member
Except the testosterone not bound to SHBG is considered "free", even though it is technically bound to a protein in blood plasma (Albumin).
You ask and you shall receive!
Edit: Technically all the "free" testosterone on the right side is also bio-available testosterone too. I know, it's confusing as hell.
Is there a Testosterone for dummies version?
halfwit
I like turtles.
Is there a Testosterone for dummies version?
Yes.
Testosterone good.
Prolactin bad.
Free testosterone very good.
Estradiol bad. But need some.
Bio-available testosterone very good too.
Four and a half hours of sleep is not good.
Spunkey71
New member
Yes.
Testosterone good.
Prolactin bad.
Free testosterone very good.
Estradiol bad. But need some.
Bio-available testosterone very good too.
Four and a half hours of sleep is not good.
What would be considered a good free Test number, my doctor seems to put a little more stock into a persons free Test number rather than there TT number?
halfwit
I like turtles.
The upper range of course is desired. I'm one of those that doesn't put a lot of stock into docs using this as a means to judge testosterone replacement therapy (TRT) effectiveness though as SHBG most certainly effects this value - which is different for everyone. Free T is the only test that I've been popped for by my doc. Thankfully, he's pretty clueless and ordered it on accident. Proviron + testosterone replacement therapy (TRT) = triple the upper range... OOPS!
For your reference: 35-155ng/dL is the average range seen in labs.
halfwit
I like turtles.
Free T is the amount of hormone not bound to (rendering it unused for anabolic purposes) SHBG. We want a lower SHBG, but not too low as you do need bound testosterone for other purposes. There's actually some research going on with testosterone replacement therapy (TRT) non-responders that have too low of an SHBG; somehow rendering (as the theory goes) exogenous testosterone useless for them. I don't know the science behind this theory to be honest, but as the body tends to like things in a certain balance (think E2 vs. TT), it makes some sense to me.
