Testosterone, often referred to as the "male hormone," plays a crucial role in various aspects of health and well-being. It influences muscle mass, bone density, mood, and even sexual function. However, not all testosterone is created equal. The two main types are total and free and they function differently in the body. Read on to find out the difference between free and total testosterone, how to know if your levels are too low, and what you can do to increase them.
Key takeaways
Total testosterone refers to all forms of testosterone circulating in your bloodstream.
Free testosterone refers to the amount that is bioavailable, meaning it’s available for use in your body.
When it comes to free vs total testosterone, free is considered a more accurate indicator of low testosterone.
However, there is no one-size-fits-all number for optimal testosterone. Deciding to treat low testosterone should always rely more on symptoms and less on numbers.
Understanding your testosterone levels
As you grow older, your testosterone (T) levels gradually decrease, leading to symptoms like low libido, more body fat, and lethargy. But when it comes to maintaining optimal T levels, there is no one-size-fits-all number. Testosterone thresholds vary across men, especially if they are different ages. Therefore, deciding to treat low testosterone should rely more on symptoms and less on numbers.
Symptoms of low testosterone typically include:
Reduced libido
Fatigue
Decreased lean muscle mass
Irritability
Erectile dysfunction
Depression
Hair loss
Bone loss
Poor memory
Low sperm count
Total vs free testosterone
The most common testosterone tests measure both total and free testosterone. Differentiating between these two forms is a crucial part of understanding how this hormone works in your body as well as how to raise your T levels to improve your overall health.
What is total testosterone?
Total testosterone refers to all forms of testosterone circulating in your bloodstream. This measurement includes both the biologically active and bound forms of the hormone. The majority of testosterone in your body is bound to plasma proteins, primarily sex hormone-binding globulin (SHBG) and albumin. Approximately 70% of testosterone is tightly bound to SHBG while the other 20–30% is weakly bound to albumin. Though testosterone bound to albumin is considered bioavailable, all bound forms are not as readily active, meaning they will not have the same effects on the body that free testosterone does.
What does free testosterone mean?
Free testosterone refers to the amount of testosterone that is bioavailable (meaning it’s available for use in your body) and active. Free testosterone is considered a more accurate indicator of low testosterone. Your body uses free testosterone for important functions like your sex drive, hair growth, muscle gains, and even your cognitive functioning. Only 1-2% of your testosterone is unbound and free for use, and these levels will typically fall faster than your total testosterone. In fact, it’s entirely possible to have normal levels of total testosterone, but low levels of free testosterone.
What are optimal T levels?
When most people talk about their testosterone levels, they are referring to total testosterone, which is the form most commonly tested. The range considered normal in most laboratories is 300 to 800 ng/dL, but this number does not indicate how much of that testosterone is free. At the same time, this bracket presents such a wide range that it isn’t always clinically meaningful beyond simply diagnosing hypogonadism and also doesn’t take symptoms into account. Rather, we suggest focusing on a target range which is within +/- 1 standard deviation (SD) of the mean.
How to calculate free testosterone
Although a total testosterone test may measure both free and bound testosterone, your results are not always straightforward. If your doctor suspects you have low T levels, they may order a separate test to measure only your free testosterone, which is reported in picograms per deciliter of blood (pg/dL). This type of test is not very common.
Another uncommon test measures all bioavailable testosterone, which includes free and albumin-bound testosterone. This test leaves out the unusable SHBG-bound testosterone. Like a total testosterone test, this test is also commonly reported in nanograms (ng) per deciliter (dL) aka ng/dL.
What is the optimal target range for free and total testosterone?
However, it’s important to note these values may vary based on the particular reference range determined by the testing lab. What is considered “optimal” should always take a person’s overall health and symptoms into account. You should also perform the test in the morning, which is when T levels tend to be highest.
Factors affecting free and total testosterone levels
A number of factors affect free and total testosterone levels. They include:
Age: Total and free T levels both decline gradually with age.
Elevated SHBG levels: When SHBG levels are too high, it’s likely that your free testosterone levels are also low.
Medical conditions: Obesity, diabetes, and endocrine disorders can all impact your T levels.
Medications: Some medications, such as antiandrogens, gonadotropin-releasing hormone agonists, and even cannabis, may alter the hypothalamic-pituitary testicular axis and affect testosterone production.
Lifestyle factors: A poor diet, lack of sleep, and chronic stress can all significantly drive your T levels down.
How to raise free testosterone
Whether you have low testosterone levels or you are curious about optimizing your free T levels for better sex, increased muscle gains, and more energy, it can be tempting to consider testosterone replacement therapy (TRT). However, there are a number of risks associated with TRT that should be considered, especially if you are hoping to have children one day. These risks include decreased sperm count and quality, testicular shrinkage, enlarged prostate, and breast growth. TRT also shuts down your body’s ability to make testosterone naturally, potentially leading to dependency.
But TRT isn’t the only way. Selective Estrogen Receptor Modulators (SERMs) like enclomiphene citrate approach low T levels with a restorative approach. SERMs stimulate the production of the hormones LH and FSH to produce more of your body’s own testosterone without compromising your fertility.
You can also make lifestyle changes to naturally support your body’s T levels, including following a healthy diet, getting adequate sleep, exercising regularly, maintaining a healthy weight, reducing your stress levels, and limiting exposure to endocrine disruptors like BPA and plastics.
The Maximus King Protocol offers a comprehensive approach to optimizing your testosterone levels. This protocol combines enclomiphene with tailored health coaching, and includes CLIA-certified lab tests to establish a baseline for your free and total T levels and monitor your progress to ensure you’re getting the most you can from the medication.
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