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Low SHBG and Estradiol by Dr. Marianco.
The most common cause of low SHBG is excessive insulin - i.e. insulin resistance. Insulin resistance in turn leads to a cascade of events which results other hormone imbalances such as low testosterone production, suboptimal thyroid hormone activity, adrenal fatigue, etc.
Factors which together in a balance determine SHBG are:
1. Anabolic hormones generally reduce SHBG. These include testosterone, DHEA, insulin, DHT, and growth hormone.
2. Thyroid hormone, Estrogens, and Progesterone (by increasing estrogen receptors/sensitivity), increase SHBG.
In the absence of insulin resistance, the most common other cause of low SHBG is a very high level of other anabolic hormones - most frequency high testosterone from TRT. Those who use anabolic steroids at high doses often drive their SHBG to near zero.
When total testosterone is between 650 to 1000 ng/dl, and a person still has zero sex drive, I would look for other causes for sexual dysfunction - e.g. other hormone, neurotransmitter, or immune system problems.
Raising SHBG does not necessarily increase the risk for Alzheimer's disease. It is important to keep in mind the factors which lead to the risk of Alzheimer's disease.
Insulin resistance (i.e. excessive insulin levels) causes low SHBG. It also greatly increases the risk of Alzheimer's disease because it results in a higher level of inflammatory cytokine production (Cytokines are the chemical messengers of the immune system). It is the inflammation which is one of the underlying factors which leads to Alzheimer's disease.
SHBG level is most often a signal of the overall status of multiple hormone levels. The balance may give an indication of whether one is in an pro-inflammatory state or anti-inflammatory state - with inflammation leading to disease such as Alzheimer's disease, heart disease, strokes, cancer, etc. Some hormones such as some estrogens and insulin can lead to inflammation leading to illness. And other hormones such as the androgens (except DHT), growth hormone, and thyroid hormone, can lead to an antiinflammatory state, reducing the risk for illness. The balance determines the person's risk for illness.
What estradiol level is best for any individual often needs to be determined by trial and error. It is unique for each individual. Most do best around 30 pg/ml. But some do best at lower and higher levels. For example, I have a 65 y.o. patient with a total testosterone of 840 ng/dl and an estradiol of 47 pg/ml. He's having the time of his life - able to make love numerous times each night - after more than a decade of having no sex. The estradiol level works for him without side effects. Some may do better with much loser levels of estradiol - the response is highly individualistic.
Even with low SHBG - which is difficult to correct since it depends on the balance of so many hormones - when the other hormones and neurotransmitters are optimized, sex drive and the ability to have an erection can often return.
When total testosterone is supraphysiologic - i.e. over 1000 ng/dl - problems with libido and erections may occur. Testosterone increases dopamine in the brain in order to increase sex drive, reduce depression, give pleasure to activities. The problem is that dopamine is a very fragile neurotransmitter/hormone in its effects. Too high a dopamine level can cause tolerance to dopamine. This is similar to how one can develop tolerance to drugs such as cocaine and amphetamines which increase dopamine levels in the brain to cause their high. This can lead to the loss of libido when high testosterone levels are maintained for long periods of time.
Conversely, when one is deprived of testosterone (and hence dopamine) for long periods of time due to hypogonadism, one can get a high during the first few weeks of testosterone treatment since the brain becomes supersensitive to dopamine when it has been deprived of it (e.g. making more dopamine receptors to pick up the weaker dopamine signals). Unfortunately, as the brain then gets use to the higher dopamine levels, it will develop some tolerance, and libido will drop off - though we often wish that hopefully a good amount remains.
Free Testosterone will be determined by how much albumin is present to bind to testosterone (weakly bound testosterone), and how much SHBG is present to bind to testosterone (strongly bound testosterone). Albumin production is fairly stable and difficult to change without severe illness present. The albumin concentration is primarily determined by hydration - with dehydration increasing its level. SHBG is modified by multiple hormones: increased by thyroid, estrogens, progesterone; lowered by testosterone, DHT, DHEA, growth hormone, insulin; and is modified up or down by some medications, etc.
Is Free Testosterone a good measure of testosterone activity to determine whether nor not to adjust the testosterone dose? Not really.
First, Free Testosterone not a reliable test.
Secondly, and more importantly, it is also determined by multiple factors. It is more a measure of the sum of these factors than of testosterone activity itself.
For example, if there is too much estrogen, free testosterone can be lower since SHBG will be higher. If there is too little thyroid hormone, free testosterone can be higher. If there is insulin resistance (i.e. too much insulin), free testosterone will be higher. And so on. Thus, what is being measured by free testosterone? Certainly much more than testosterone activity itself. Therefore, it is difficult to say determine what needs to be adjusted to optimize function if free testosterone is used as the primary measure.
If anything, high or low free testosterone indicates there is a good chance that other hormonal imbalances (besides testosterone) are also occurring which need to be assessed and addressed - e.g. hypothyroidism, insulin resistance, high estradiol levels, etc.
Testosterone activity is determined by the sum of free testosterone's activity, weakly bound testosterone's activity (which has partial activity), and SHBG- bound testosterone activity (testosterone has signaling activity to SHBG receptors when bound to SHBG). Thus, Total testosterone comes closest to describing testosterone activity for clinical decision-making purposes for testosterone dosing.
One can also add DHT's activity (as some practitioners do) but one has to be careful since DHT can counteract testosterone's activity when DHT is too high.
How can one decide that the testosterone dose is too high or too low?
Using total testosterone, the TRT decisions become very simple:
1. The goal of TRT is getting the average total testosterone to at least 650 ng/dl (midrange on a reference scale from 300-1000 ng/dl).
2. If any problems remain, then it is due to other neurotransmitter/hormone/cytokine imbalances or excessive testosterone dose (i.e. supraphysiologic total testosterone).
These two constitute a rule of thumb - determined by the individual patient's circumstance - some patients need a lower, some patients need a higher dose of testosterone. However, no matter what the dose, realize that other imbalances in the body's information processing system (i.e. the sum of the nervous system, endocrine system, and immune system activities) may be present and need to be addressed.
Whether the total testosterone level over time is flat (as with pellets and usually alcohol-based gels) or with peaks or valleys (e.g. with testosterone injections, oil-based creams) is determined by the route of administration and the person's half-life for testosterone (and the ester if injections are used). Whether a flat or peak/valley testosterone time-curve is preferred depends on what a person best responds to.
Given how large an overlap there is between the symptoms of testosterone deficiency, thyroid hormone deficiency, cortisol deficiency, insulin resistance/diabetes, etc., it is important to look at the other hormones for a solution if total testosterone is at a good level.
How much estradiol (E2) is made depends a lot on how high total testosterone becomes and how much aromatase activity is present.
HCG use increases the production of aromatase - increasing estradiol production.
High testosterone doses (such as injections given once every two weeks), results in long-lasting supraphysiologic levels of estradiol. A solution in this case is to use smaller and more frequent doses of testosterone (such as by going to a twice a week injection - rather than larger once a week or once every two week injections). The lower peak testosterone levels resulting from more frequent injections reduces the exposure to aromatase, resulting in smaller estradiol levels. At the extreme, testosterone pellets usually have the least problems with estradiol. Of course, using Arimidex can also reduce estradiol.
The most common cause of low SHBG is excessive insulin - i.e. insulin resistance. Insulin resistance in turn leads to a cascade of events which results other hormone imbalances such as low testosterone production, suboptimal thyroid hormone activity, adrenal fatigue, etc.
Factors which together in a balance determine SHBG are:
1. Anabolic hormones generally reduce SHBG. These include testosterone, DHEA, insulin, DHT, and growth hormone.
2. Thyroid hormone, Estrogens, and Progesterone (by increasing estrogen receptors/sensitivity), increase SHBG.
In the absence of insulin resistance, the most common other cause of low SHBG is a very high level of other anabolic hormones - most frequency high testosterone from TRT. Those who use anabolic steroids at high doses often drive their SHBG to near zero.
When total testosterone is between 650 to 1000 ng/dl, and a person still has zero sex drive, I would look for other causes for sexual dysfunction - e.g. other hormone, neurotransmitter, or immune system problems.
Raising SHBG does not necessarily increase the risk for Alzheimer's disease. It is important to keep in mind the factors which lead to the risk of Alzheimer's disease.
Insulin resistance (i.e. excessive insulin levels) causes low SHBG. It also greatly increases the risk of Alzheimer's disease because it results in a higher level of inflammatory cytokine production (Cytokines are the chemical messengers of the immune system). It is the inflammation which is one of the underlying factors which leads to Alzheimer's disease.
SHBG level is most often a signal of the overall status of multiple hormone levels. The balance may give an indication of whether one is in an pro-inflammatory state or anti-inflammatory state - with inflammation leading to disease such as Alzheimer's disease, heart disease, strokes, cancer, etc. Some hormones such as some estrogens and insulin can lead to inflammation leading to illness. And other hormones such as the androgens (except DHT), growth hormone, and thyroid hormone, can lead to an antiinflammatory state, reducing the risk for illness. The balance determines the person's risk for illness.
What estradiol level is best for any individual often needs to be determined by trial and error. It is unique for each individual. Most do best around 30 pg/ml. But some do best at lower and higher levels. For example, I have a 65 y.o. patient with a total testosterone of 840 ng/dl and an estradiol of 47 pg/ml. He's having the time of his life - able to make love numerous times each night - after more than a decade of having no sex. The estradiol level works for him without side effects. Some may do better with much loser levels of estradiol - the response is highly individualistic.
Even with low SHBG - which is difficult to correct since it depends on the balance of so many hormones - when the other hormones and neurotransmitters are optimized, sex drive and the ability to have an erection can often return.
When total testosterone is supraphysiologic - i.e. over 1000 ng/dl - problems with libido and erections may occur. Testosterone increases dopamine in the brain in order to increase sex drive, reduce depression, give pleasure to activities. The problem is that dopamine is a very fragile neurotransmitter/hormone in its effects. Too high a dopamine level can cause tolerance to dopamine. This is similar to how one can develop tolerance to drugs such as cocaine and amphetamines which increase dopamine levels in the brain to cause their high. This can lead to the loss of libido when high testosterone levels are maintained for long periods of time.
Conversely, when one is deprived of testosterone (and hence dopamine) for long periods of time due to hypogonadism, one can get a high during the first few weeks of testosterone treatment since the brain becomes supersensitive to dopamine when it has been deprived of it (e.g. making more dopamine receptors to pick up the weaker dopamine signals). Unfortunately, as the brain then gets use to the higher dopamine levels, it will develop some tolerance, and libido will drop off - though we often wish that hopefully a good amount remains.
Free Testosterone will be determined by how much albumin is present to bind to testosterone (weakly bound testosterone), and how much SHBG is present to bind to testosterone (strongly bound testosterone). Albumin production is fairly stable and difficult to change without severe illness present. The albumin concentration is primarily determined by hydration - with dehydration increasing its level. SHBG is modified by multiple hormones: increased by thyroid, estrogens, progesterone; lowered by testosterone, DHT, DHEA, growth hormone, insulin; and is modified up or down by some medications, etc.
Is Free Testosterone a good measure of testosterone activity to determine whether nor not to adjust the testosterone dose? Not really.
First, Free Testosterone not a reliable test.
Secondly, and more importantly, it is also determined by multiple factors. It is more a measure of the sum of these factors than of testosterone activity itself.
For example, if there is too much estrogen, free testosterone can be lower since SHBG will be higher. If there is too little thyroid hormone, free testosterone can be higher. If there is insulin resistance (i.e. too much insulin), free testosterone will be higher. And so on. Thus, what is being measured by free testosterone? Certainly much more than testosterone activity itself. Therefore, it is difficult to say determine what needs to be adjusted to optimize function if free testosterone is used as the primary measure.
If anything, high or low free testosterone indicates there is a good chance that other hormonal imbalances (besides testosterone) are also occurring which need to be assessed and addressed - e.g. hypothyroidism, insulin resistance, high estradiol levels, etc.
Testosterone activity is determined by the sum of free testosterone's activity, weakly bound testosterone's activity (which has partial activity), and SHBG- bound testosterone activity (testosterone has signaling activity to SHBG receptors when bound to SHBG). Thus, Total testosterone comes closest to describing testosterone activity for clinical decision-making purposes for testosterone dosing.
One can also add DHT's activity (as some practitioners do) but one has to be careful since DHT can counteract testosterone's activity when DHT is too high.
How can one decide that the testosterone dose is too high or too low?
Using total testosterone, the TRT decisions become very simple:
1. The goal of TRT is getting the average total testosterone to at least 650 ng/dl (midrange on a reference scale from 300-1000 ng/dl).
2. If any problems remain, then it is due to other neurotransmitter/hormone/cytokine imbalances or excessive testosterone dose (i.e. supraphysiologic total testosterone).
These two constitute a rule of thumb - determined by the individual patient's circumstance - some patients need a lower, some patients need a higher dose of testosterone. However, no matter what the dose, realize that other imbalances in the body's information processing system (i.e. the sum of the nervous system, endocrine system, and immune system activities) may be present and need to be addressed.
Whether the total testosterone level over time is flat (as with pellets and usually alcohol-based gels) or with peaks or valleys (e.g. with testosterone injections, oil-based creams) is determined by the route of administration and the person's half-life for testosterone (and the ester if injections are used). Whether a flat or peak/valley testosterone time-curve is preferred depends on what a person best responds to.
Given how large an overlap there is between the symptoms of testosterone deficiency, thyroid hormone deficiency, cortisol deficiency, insulin resistance/diabetes, etc., it is important to look at the other hormones for a solution if total testosterone is at a good level.
How much estradiol (E2) is made depends a lot on how high total testosterone becomes and how much aromatase activity is present.
HCG use increases the production of aromatase - increasing estradiol production.
High testosterone doses (such as injections given once every two weeks), results in long-lasting supraphysiologic levels of estradiol. A solution in this case is to use smaller and more frequent doses of testosterone (such as by going to a twice a week injection - rather than larger once a week or once every two week injections). The lower peak testosterone levels resulting from more frequent injections reduces the exposure to aromatase, resulting in smaller estradiol levels. At the extreme, testosterone pellets usually have the least problems with estradiol. Of course, using Arimidex can also reduce estradiol.