Testosterone deficiency (or hypogonadism) often leads to a disturbing list of possible symptoms: for example, we could gain weight more easily (in the form of fat, not muscle) or detect less than usual sexual desire. But we may also feel as if constant lethargy is stifling our mind’s ability to concentrate, make quick and accurate decisions and feel good.
If we are experiencing these or other signs, one of the possible houses could be residing in an imbalance of our testosterone levels.
Having normal testosterone levels is important regardless of sex because testosterone is an absolutely essential hormone for a healthy metabolism. (For example, optimal testosterone levels help the body burn fat and increase muscle mass.) The advice is therefore to check our blood testosterone levels.
To determine your testosterone level, blood tests measure specific markers in your body such as total testosterone or free testosterone.
The free testosterone test is useful because it is a marker that can give us a better understanding of our ailments. But what is the difference between total testosterone and free testosterone?
In men, most testosterone is produced by the testes through a complex series of biochemical reactions – which convert cholesterol to testosterone (the adrenal glands also produce testosterone).
Testosterone molecules are then secreted directly into the bloodstream, where many of them soon bind to other molecules known as sex hormone-binding globulin or SHBG (testosterone, as you may know, is a sex hormone). Other testosterone molecules bind to albumin, an important type of blood protein.
What about the rest of testosterone, unbound testosterone? This testosterone is – appropriately – called “free testosterone”, or free T because it is not attached to other molecules. Our body actively uses free T molecules since they are free to enter the body’s cells – without hindrance from SHBG or albumin – to perform their function as signaling molecules that regulate metabolism and other cellular functions. (Testosterone molecules bound to other proteins cannot enter most cells.)
Total testosterone is a measure of how much testosterone we have in our blood in total, both free and bound. (So we would always have a higher total T level than free T.)
In general, if the SHBG binding molecules are higher we will have lower levels of free T. With more SHBG molecules in the blood, more of our testosterone will indeed be bound and not free at all.
Suppose a man is experiencing some of the symptoms of hypogonadism (testosterone deficiency), such as low libido, difficulty concentrating, poor ability to concentrate or constant low energy. So he decides to measure his total testosterone but finds that his total T level is perfectly normal. However, it is experiencing very real symptoms, typical of hypogonadism. What could be the problem then?
It turns out that the symptoms of testosterone deficiency are not only caused by the total amount of testosterone testosterone enanthate en venta en espana in the blood. When it comes to hypogonadism, the level of free T is also important, because free T is what your body has readily available in the bloodstream. So we may have normal total T levels but still suffer from the grueling consequences of testosterone deficiency because our free T levels are too low (which may be due to a high amount of SHBG in the blood).
Therefore, free T levels may shed light on why many patients report signs of testosterone deficiency, even though total T levels are normal. In fact, research suggests that free T levels are a better predictor of testosterone deficiency symptoms than total T levels. Also, low total T levels don’t necessarily indicate a testosterone-related health problem, as this may simply be a “side effect” of something else going on in your body.
For example, obesity can lead to a decrease in total T levels, as insulin resistance – a common consequence of obesity – reduces SHBG levels, also causing the total T levels to drop. However, in a scenario like this, free T is not affected and remains at a normal level.
Hence, low levels of total Testosterone may be a reflection of a non-perfect metabolic balance in our body, low levels of free T can help us identify a possible cause of testosterone deficiency symptoms.