Testosterone Markers & Measurements:
Measuring Testosterone levels is not as straightforward as it can appear. There are five distinct categories that define total Testosterone markers and levels: total, free, bound (Albumin + SHBG), and bioavailable (free + Albumin).
Total Testosterone
is the absolute total testosterone circulating in your bloodstream. A "Total" Testosterone lab test measures free testosterone as well as what is bound to the proteins albumin and sex hormone binding globulin (SHBG).
Free Unbound Testosterone
is most important here, as it’s the amount that is bioavailable and available for use in your body. Only around 1-3% on average of your Total Testosterone is considered free.
Bound Testosterone
binds to two types of proteins, Albumin and SHBG (Sex Hormone Binding Globulin).
Albumin
Considered the most abundant protein in your blood; around 50% of Testosterone in your body is attached to Albumin. When testosterone binds to Albumin, it is considered bioavailable but is not as readily active as unbound Testosterone would be. This might sound totally confusing but know that it’s not what’s considered free but it accounts for what’s bioavailable in your bloodstream, which includes your free/unbound amounts.
SHBG
Sex Hormone Binding Globulin is a protein that’s made in the liver and attaches itstelf to sex hormones, primarily Testosterone, and removes it from direct utilization in the body. One bound, it inhibits Testosterone really from doing anything of use in the body, hence why SHBG bound T is unavailable to your body. High levels of SHBG can throw off what’s actually available (free) for your bodies to use, so it’s important to differentiate this from what’s bioavailable.
Target Testosterone Ranges
Numbers are not the whole story—it matters much more how you look, feel, and function. So it’s super important to feel into how your body functions as a comparable reference to these quantitative averages and numbers. Consider the numbers as one part of the story of how YOU are optimizing your Testosterone, the other part is dependent on how YOU are feeling into your body and tracking its changes. We’ll be discussing more in detail on how to optimize your function later.
