Free T vs Total T - Cutoffs and Symptoms - Where Are the Data?
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madman
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As I have stressed in previous threads keep in mind that the bound fractions albumin/SHBG still serve a purpose and are not useless binding proteins as many stinking up all those so called HRT/men's health forums let alone those so called gurus polluting the net CLAIM!
As I have been preaching numerous times on the forum over the years although TT is important to know FT is what truly matters as it is the unbound fraction of T responsible for the positive effects.
As of now the true heavyweights in the field Dr. Bhasin and Dr. Jasuja (Brigham and Women's Hospital)), Dr. Fiers and his team (UZ Ghent), the father of testosterone Dr. Morgentaler and numerous top uros/andrologists including, Dr. Zitzmann, Dr, Traish, Dr. Corona, Dr. Anawalt, Dr. Khera, Dr. Mulhall and I could throw many more in there too that have been stressing the importance of the most critical fraction free testosterone!
* All BPs, whether specific or non-specific, together control tissue availability and metabolic clearance rate of a given hormone through regulation of the free hormone fraction. In the free hormone hypothesis, it is mostly this free fraction, and by extension the free hormone concentration, that accounts for the biological activity of hormone action
Misconceptions About Bioavailable T
*Hammes A, et al: 2005 Cell.
Pay attention to 25:40-34:36 of the presentation where he explains the importance of measuring free testosterone using a standardized Equilibrium Dialysis method!
Explains the complexity T:SHBG and T:estradiol binding!
* the experimental data does not conform to the linear model (Vermeulen) of testosterones binding and we've shown this also for estradiol, so both for estradiol and testosterone the experimental data do not conform to the linear model, in addition what we have found is that the apparent binding affinity varies dynamically with changes in estradiol and SHBG concentrations
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journals.lww.com
INTRODUCTION
Clinical practice guidelines on the diagnosis of male hypogonadism focus on clinical signs and symptoms of androgen deficiency, as well as biochemical assessment of low circulating testosterone (T). However, there is a longstanding debate, as well as a persisting controversy concerning biochemical assessment of serum T and in particular the use (and misuse) of free T. Free T, as advocated by the free hormone hypothesis, represents...
As I have been preaching numerous times on the forum over the years although TT is important to know FT is what truly matters as it is the unbound fraction of T responsible for the positive effects.
As of now the true heavyweights in the field Dr. Bhasin and Dr. Jasuja (Brigham and Women's Hospital)), Dr. Fiers and his team (UZ Ghent), the father of testosterone Dr. Morgentaler and numerous top uros/andrologists including, Dr. Zitzmann, Dr, Traish, Dr. Corona, Dr. Anawalt, Dr. Khera, Dr. Mulhall and I could throw many more in there too that have been stressing the importance of the most critical fraction free testosterone!
* All BPs, whether specific or non-specific, together control tissue availability and metabolic clearance rate of a given hormone through regulation of the free hormone fraction. In the free hormone hypothesis, it is mostly this free fraction, and by extension the free hormone concentration, that accounts for the biological activity of hormone action
Misconceptions About Bioavailable T
*Hammes A, et al: 2005 Cell.
Pay attention to 25:40-34:36 of the presentation where he explains the importance of measuring free testosterone using a standardized Equilibrium Dialysis method!
Explains the complexity T:SHBG and T:estradiol binding!
* the experimental data does not conform to the linear model (Vermeulen) of testosterones binding and we've shown this also for estradiol, so both for estradiol and testosterone the experimental data do not conform to the linear model, in addition what we have found is that the apparent binding affinity varies dynamically with changes in estradiol and SHBG concentrations
Where it stands as of now.
Summed up here!
Dr. Bhasin and Dr. Jasuja Xyone therapeutics 2025!
reporter.nih.gov
ABSTRACT
Background
Measurement of free testosterone (T) concentrations is indicated in the diagnosis of androgen disorders, including hypogonadism in men; hirsutism, polycystic ovary syndrome (PCOS), and androgenic alopecia in women; pubertal disorders in boys and management of gender affirming hormone therapies for transgender and gender diverse (TGD) persons. This Phase IIB proposal...
Summed up here!
Dr. Bhasin and Dr. Jasuja Xyone therapeutics 2025!
RePORT 〉 RePORTER
ABSTRACT
Background
Measurement of free testosterone (T) concentrations is indicated in the diagnosis of androgen disorders, including hypogonadism in men; hirsutism, polycystic ovary syndrome (PCOS), and androgenic alopecia in women; pubertal disorders in boys and management of gender affirming hormone therapies for transgender and gender diverse (TGD) persons. This Phase IIB proposal...
We do it big here at Nelson's stomping ground!
Dr. Leen Antonio (UZ Leuven)!
She has collaborated with the heavyweights in the field Dr. Bhasin and Dr. Jasuja (Brigham and Women's Hospital)), Dr. Fiers and team (UZ Ghent) on research related to free testosterone.
Dr. Leen Antonio (UZ Leuven)!
She has collaborated with the heavyweights in the field Dr. Bhasin and Dr. Jasuja (Brigham and Women's Hospital)), Dr. Fiers and team (UZ Ghent) on research related to free testosterone.
As usual Nelson's house is where it's at!
event.on24.com
Testosterone imbalances affect men, women, and children differently. In males, testosterone deficiency (hypogonadism) can lead to low libido, fatigue, and muscle loss, while excess may contribute to aggression and cardiovascular risks. In females, testosterone excess (hyperandrogenism), often associated with polycystic ovary syndrome (PCOS) or adrenal disorders, can cause excess hair growth, weight gain, and menstrual irregularities. In children...
Importance of free testosterone measurement in assessing androgen disorders
Thursday, March 27, 2025 at 1:00 PM Eastern Daylight Time.
Testosterone imbalances affect men, women, and children differently. In males, testosterone deficiency (hypogonadism) can lead to low libido, fatigue, and muscle loss, while excess may contribute to aggression and cardiovascular risks. In females, testosterone excess (hyperandrogenism), often associated with polycystic ovary syndrome (PCOS) or adrenal disorders, can cause excess hair growth, weight gain, and menstrual irregularities. In children...
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Use of calculated free testosterone in men: advantages and... : Current Opinion in Endocrinology, Diabetes and Obesity
hting its relevance in preventing misdiagnosis and overtreatment of male hypogonadism. Recent findings While there is consensus on measuring total T – comprising sex hormone-binding globulin (SHBG)-bound, albumin-bound, and free T – as a first step in diagnosing male hypogonadism, evidence...
journals.lww.com
INTRODUCTION
Clinical practice guidelines on the diagnosis of male hypogonadism focus on clinical signs and symptoms of androgen deficiency, as well as biochemical assessment of low circulating testosterone (T). However, there is a longstanding debate, as well as a persisting controversy concerning biochemical assessment of serum T and in particular the use (and misuse) of free T. Free T, as advocated by the free hormone hypothesis, represents...
madman
Super Moderator
Key Concepts - Tissue Thresholds
Key Concept - Different Thresholds
* Different symptoms/findings will manifest at different thresholds
* But there is variability between individuals as well, these are just averages
* While this average libido may be right here say 550 ng/dL or so your gonna have some people that its not until 700 ng/dL and your gonna have some people that its around 300 ng/dL so you have that natural variability in each of the populations that creates that spread
Combined Concepts
* Set the threshold at say at 200 (6.9 ng/dL) for a study your gonna capture all those with low PSA, most anemias, some osteopenia, and a very small percentage of the libido group so you have to take that into account when interpreting the data for that particular threshold so again you will have high sensitivity for some things low specificity and vice versa as that flips
* Now you set it again a little bit higher say at 400 (13.9 ng/dL) now you are going to capture all the measures but your not very specific for any of the measures so your going to capture all these people but your treatment isn't going to be very effective
Key Concept - Different Thresholds
* Different symptoms/findings will manifest at different thresholds
* But there is variability between individuals as well, these are just averages
* While this average libido may be right here say 550 ng/dL or so your gonna have some people that its not until 700 ng/dL and your gonna have some people that its around 300 ng/dL so you have that natural variability in each of the populations that creates that spread
Combined Concepts
* Set the threshold at say at 200 (6.9 ng/dL) for a study your gonna capture all those with low PSA, most anemias, some osteopenia, and a very small percentage of the libido group so you have to take that into account when interpreting the data for that particular threshold so again you will have high sensitivity for some things low specificity and vice versa as that flips
* Now you set it again a little bit higher say at 400 (13.9 ng/dL) now you are going to capture all the measures but your not very specific for any of the measures so your going to capture all these people but your treatment isn't going to be very effective
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