There’s a good reason why testosterone is often referred to as The King of Hormones. It plays a vital role in a bunch of crucial bodily processes such as maintaining our libido, muscle mass, bone mass etc. But did you know that there are actually different types of testosterone coursing through our veins? Well, there are. So, what about the difference between testosterone vs free testosterone?
Testosterone is the main sex hormone in men, while free testosterone is the free or unbound type of the total testosterone that’s found in the body.
Free T makes up approximately 2% of all testosterone in the bloodstream.
About 98% of all testosterone is the bound version of our primary male hormone.
Basically, this is the most easy-to-digest explanation of the difference between the two.
But there are actually 3 different forms of testosterone in the human body, so let’s take a look at the differences between each.
What Is The Difference Between Total, Free And Bioavailable Testosterone?
Total testosterone represents all 3 testosterone types in the body – SHBG-bound testosterone, albumin-bound testosterone and free testosterone.
However, free testosterone is part of the so-called bioavailable testosterone.
You see, bioavailable testosterone includes albumin-bound testosterone and free testosterone.
These two forms are the only ones that the body’s tissues can make use of, unlike SHBG-bound T.
But to make it easier for you to grasp the concept, here are the 3 forms of testosterone that we all have in our bodies:
- Bioavailable testosterone – Albumin-bound testosterone and Free testosterone
- Bound testosterone – Sex hormone-binding globulin-bound Testosterone
Thus, all 3 kinds of testosterone in the body fall under the same umbrella – total testosterone.
It’s just that the free and albumin-bound testosterone forms are considered bioavailable.
In contrast, the SHBG-bound (sex hormone-binding globulin) testosterone isn’t available to our cells.
And now, let’s take a closer look at each form of testosterone:
1. Sex Hormone-Binding Globulin + Testosterone
SHBG is a protein that the liver produces and its main purpose is to transport our sex hormones, hence the name.
This means that it has a high affinity to hormones like testosterone.
More specifically, around 45% of the total testosterone that floats in our systems is the inactive SHBG-bound version of T.
This kind of testosterone is considered biologically inactive because our cells can’t use it.
So, the SHBG-bound T has no effect on us as it’s virtually inactive.
Even worse, having high levels of this type of testosterone might mean that you have low levels of free testosterone.
That’s why high levels of SHBG-bound testosterone might falsy elevate your total T values.
In return, this can mask a potentially low bioavailable testosterone when doing blood tests for total T.
2. Free Testosterone
This form of testosterone is the most valuable one if you want to increase your muscle mass, boost your sex drive and just become manlier.
Unfortunately, it makes up only around 2% of the total T levels in the bloodstream.
But it’s so potent that even 2% of it can have an impact on your physique and overall well-being.
Now, as the name suggests, this type of T floats freely as it’s not bound to any protein.
This means that it’s readily available to be used by the body’s tissues.
So, in an ideal world, we’d want more of this type of testosterone and less of the sex hormone-binding globulin one.
3. Albumin + Testosterone
In a similar fashion to SHBG, albumin is a protein that’s produced by the liver.
This is one of the most important proteins in the body as it constitutes about 60% of all protein in the body.
However, as opposed to SHBG, albumin has a lower affinity to testosterone.
It doesn’t bind to the King of Hormones so tightly, thus being considered bioavailable testosterone.
Although not as potent as free T, albumin-bound testosterone can still be used by the tissues in the body.
And it makes up about 53% of all testosterone so its use shouldn’t be neglected.
What Increases Free Testosterone?
The same things that increase your overall testosterone in general:
- Working out (mainly weightlifting i.e. hitting the gym)
- Eating testosterone boosting foods (pomegranate, oysters etc.)
- Getting enough quality sleep
- Reducing stress
- Using testosterone boosting supplements (e.g. TestoGen)
- Staying away from alcohol
In a nutshell, living a healthy lifestyle will boost your testosterone as a whole.
So as a result, your free T levels will also improve.
What Causes Low Free Testosterone?
These are perhaps the main contributors to low levels of free testosterone and testosterone as a whole:
- Obesity (increased body fat levels)
- Bad foods (soy, flaxseeds, junk food etc.)
- Lack of sleep
- Testicular injuries
- A sedentary lifestyle
Clearly, if you want optimal manliness you’d want to take care of these aspects related to low free testosterone levels.
And please, don’t neglect the things that lower testosterone levels.
This might lead to a plethora of unpleasant effects that plague your entire life.
Yes, I’m talking about stuff like not being able to keep an erection and having zero sex drive.
What Level Of Testosterone Is Considered Low?
Anything below 300 ng/dL can be deemed as insufficient levels of testosterone.
In fact, the normal testosterone range is between 300 ng/dL to 1000 ng/dL.
The American Urological Association suggests that if a man’s T levels are below 300, he should be diagnosed with low testosterone (1).
And on average, healthy guys produce approximately 6 to 7 milligrams of testosterone each day.
On top of that, your testosterone levels are at their highest early in the morning.
That’s why it’s advised to do blood tests for determining T levels early in the morning (before 10 AM).
But note that your T is at its lowest later in the day.
My Testosterone Level Is 140 – What Should I Do?
First and foremost, make an appointment with your GP or even better an endocrinologist.
If you did a blood test and the results showed T levels below 140 ng/dL this is a cause for concern.
Seriously, this shouldn’t be taken lightly as low testosterone will wreak havoc on your entire life.
You can also give the best testosterone booster for older men a try (I’ve personally used it and it totally works).
From increased body fat to decreased muscle mass and a hard time maintaining an erection, this is an awful condition for any man.
Now, if your levels are that low, your doc will most likely come up with testosterone replacement therapy as treatment.
Also, it may be offered to you in several different variations:
- Oral pills
- Transdermal patches
Obviously, this will probably be your best bet to get your levels back to normal as fast as possible.
Regardless, keep in mind that TRT (testosterone replacement therapy) is essentially a synthetic form of our primary male hormone.
It’s lab-made, just like anabolic steroids.
So once you finish your TRT cycle, you better focus on supplementation and improving your lifestyle.
This is the safest and most stable way of keeping your T levels within the optimal range unless you suffer from a particular condition that is.
What Should Free Testosterone Be?
According to the University of Rochester Medical Center, the normal free testosterone range is 0.3 pg/mL to 2 pg/mL (2).
Or in terms of percentages, your free T is normal if it’s anywhere from 0.1% to 0.3% of your total T.
And as you might imagine, the only feasible way to determine your levels would be through a blood test.
However, something that I find intriguing from the same source is that this medical center mentions two things that can affect your results.
Guess what they are? Alcohol and obesity.
As I previously mentioned, these two things can affect your hormonal levels.
So you better keep track of your alcohol consumption and body fat percentage!
Finally, you now know what sets apart testosterone vs free testosterone.
The term free testosterone stands for the testosterone that’s freely floating in your system and that’s readily available for use by the bodily tissues.
While testosterone generally refers to the bound testosterone i.e. SHBG-bound and albumin-bound.
The SHBG-bound T is, in fact, unusable by the body’s tissues, unlike the other two forms of testosterone.
Don’t forget that although bound, testosterone + albumin is considered bioavailable testosterone, just like free testosterone.
Thus, to sum things up, the 3 forms of T are – SHBG-bound testosterone, free testosterone and albumin-bound testosterone.
Now tell me – were you aware of the differences between T and free T?
Also – have you personally checked your levels via a blood test?
Don’t hesitate to let me know by leaving your answer in the comments below!
Why is Free Testosterone more important than Total Testosterone?
While total testosterone is an important marker of male health and vitality, free testosterone is a more accurate indicator of androgenic activity in the body.
This is because free testosterone is the form of testosterone that is most readily available to bind to androgen receptors in cells throughout the body, including muscle cells, bone cells, and cells in the brain.
How is Free Testosterone measured?
Free testosterone can be measured directly using a blood test that is specifically designed to measure free testosterone levels.
However, this type of test is less commonly used than total testosterone testing.
More commonly, a calculation is used to estimate free testosterone levels based on measurements of total testosterone, SHBG (sex hormone-binding globulin), and albumin.
What are the symptoms of Low Free Testosterone levels?
Low free testosterone levels can lead to a range of symptoms, including decreased libido, erectile dysfunction, reduced muscle mass and strength, increased body fat, decreased bone density, and depression.
Other symptoms may include fatigue, difficulty concentrating, and a decrease in overall vitality and wellbeing.
How can Free Testosterone levels be increased naturally?
There are a number of lifestyle changes that can help increase free testosterone levels naturally, including regular exercise, a healthy diet that includes plenty of protein, healthy fats, and fiber, adequate sleep, stress management techniques, and avoiding excess alcohol and drug use.
Certain supplements, such as D-aspartic acid and fenugreek, may also help boost free testosterone levels, although the evidence for their effectiveness is mixed and more research is needed.
I’ve been fascinated by natural male hormone optimization since 2016. And ever since I’ve been going through boatloads of different meta-analyses and scientific data associated with increasing testosterone levels naturally. I hold a PhD degree in public health and have 10+ scientific publications on Google Scholar. Thus, in my collective work here you’ll find helpful tricks, natural remedies, detailed product reviews (including stuff I’ve personally tried)… and more!
I've been fascinated by natural male hormone optimization since 2016. And ever since I've been going through boatloads of different meta-analyses and scientific data associated with increasing testosterone levels naturally. I hold a PhD degree in public health and have 10+ scientific publications on Google Scholar. Thus, in my collective work here you'll find helpful tricks, natural remedies, detailed product reviews (including stuff I've personally tried)... and more!