Testosterone 101

Before we start talking about Testosterone, let’s just take a step back to unpack what hormones are and why they are important in your body.
What is Testosterone? Why is it important?
Without Testosterone, we as men would not be able to perform the duties of reproduction, produce muscle, or really show defining male characteristics.
Understand that the endocrine system in your body is responsible for key bodily functions like reproduction, metabolism, sexual development, growth, and mood. It’s made up of glands that produce and release hormones into your body. Having healthy ratios of hormones is also important so your body can keep functioning in equilibrium.
Think of your hormones as chemical messengers that send signals to your tissues to complete its marching orders.
Testosterone helps with:
Sex Drive
Bone Strength
Heart Health
Energy Levels
Sperm Cell Production
Mood & Memory
In plain English, Testosterone - part of a class of androgens, aka steroids - is considered to be the prime male sex hormone. All men need Testosterone in order to be men, put simply.
Testosterone is one of the most powerful hormones in your body and we’ll be breaking it down here fully so you understand how it affects your health and well-being.
Produced mainly in the testes and in small quantities in the adrenal glands, Testosterone is responsible for the development of male sex charateristics during development and secondary sex characteristics, such as voice deeping, sperm production, increased penis + testes size, facial hair and muscle mass during adolescence and adulthood.
Beyond these primary roles, Testosterone regulates libido (sex drive), bone mass, heart health, fat distribution, muscle mass and strength, energy levels and sperm + red blood cell production. There’s validated research, too, that Testosterone plays a role in anti-inflammation and cognitive functioning including mood, memory, and dopamine production.
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Testosterone Markers & Measurements:
1 - 3%
Average of Total Testosterone is considered free
50%
The most abundant protein in your blood
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).
01
Total
Testerone 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).
02
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.
03
Bound
Testosterone binds to two types of proteins, Albumin and SHBG (Sex Hormone Binding Globulin).
04
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.
05
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.
"SHBG is the joker in the deck..."
According to Harvard Health, “anywhere from 40% to 70% of total testosterone travels around with a protein called sex hormone binding globulin (SHBG). It is bound so tightly to SHBG that it can't be released, and therefore isn't available to your cells. Consider that "SHBG is the joker in the deck," says Dr. Morgentaler, Director of Men's Health Boston. "High levels in a man can make his total testosterone appear perfectly normal even though he has every symptom in the book, and his tissues are truly deficient in testosterone."
Understanding Testosterone Levels
Understanding optimal Testosterone levels comes with a caveat: there’s no one size fits all number and you need to look at how you feel and function to tell the full story.
Varying factors play a part in understanding your optimal levels and how it fits within total amounts versus unbound/available levels, and for different age groups.
Most importantly, there’s quite a range for optimal levels (numbers discussed below), and that range also quite varies based on the time of day it’s being measured. A man measuring his T levels can change during a 24 hour cycle so it’s best to check measurements for optimization at peak time in the mornings, generally as that’s when your T levels are at its highest.
Age plays a HUGE factor for Testosterone levels and noticeable variation from young to old. There’s research that Testosterone begins a gradual decline in body after age 40 (this doesn’t mean it goes away, just that averages show a start in decline). You’ll notice that ranges typically peak around late adolescence and early adulthood and as mentioned, start to decline after age 40.
Ranges
The American Urological Association (AUA) defines success for optimizing Total Testosterone as a range between 450-600 ng/dL (middle tertile of the reference range for most labs) accompanied by symptom resolution for men who have had low Testosterone. However, these are norms for men of all ages, and also we know that ~70% of American adult men are overweight or obese.
To understand optimal ranges, let’s take a look at what this study from the Journal of Clinical Endocrinology & Metabolism published on hormone levels for healthy, non-obese young men (age range between 19-40 years old):
Normal vs. Abnormal
Normal vs. Abnormal
While most labs consider the 2.5th-97.5th percentiles (348-1197 ng/dl for Total Testosterone) “normal,” this bracket is such a wide range that it is not clinically meaningful beyond diagnosing hypogonadism (a failure of the testes to function properly). Rather, we suggest focusing on a target range which is within +/- 1 Standard Deviation (SD) of the mean.
Target Testosterone Ranges
Target Testosterone Ranges
Please note, 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.
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How is testosterone made?
The hypothalamus in your brain is the gatekeeper for the Testosterone initiation process.
Where does Testosterone production start? The hypothalamus in your brain is the gatekeeper for the Testosterone initiation process. Once the hypothalamus receives the signals to produce Testosterone, it releases a hormone called gonadotropin (GnRH) which travels down to the pituitary gland. Once there, the pituitary gland then signals and releases two hormones to stimulate Testosterone production: luteinizing hormone (LH) and follicle-stimulating hormone (FSH), known as gonadotropins. These hormones then make their way to the testes to produce Testosterone and voila, Testosterone gets released into the bloodstream! We’ll be talking in a bit about the types of Testosterone that are measured.
Once Testosterone is produced, it’s also metabolized further into two key hormones: DHT and estradiol, through enzymes called 5α-reductase and aromatase. This process, known as aromatization, helps maintain a proper Testosterone to estrogen ratio in the body. DHT is linked to body hair production, and Estradiol - the predominant form of Estrogen - supports modulating libido and erectile function. Production of estrogen is a completely normal function for physiological functioning and hormonal balance.
The body is able to regulate the production of Testosterone through the hypothalamic–pituitary–adrenal axis (HPA), also known as a negative feedback loop. When the body signals enough Testosterone has been made, it sends signals back to the hypothalamus and pituitary gland to suppress the hormone GnRH and halt Testosterone production.
How is testosterone made?How is testosterone made?
What about Estrogen?
Despite Estrogen’s association as a primary female sex hormone, this hormone is mission critical for male sexual well-being and other bodily functions such as: libidio and erectile function, sperm cell production, bone health, metabolism, and brain health.
To start, let’s breakdown what Estradiol is and why its low amounts can appear in the body. Understand that Estradiol is a product of Estrogen, which also houses Estrone and Estriol. But for you, the most important one related to male sexual function is typically Estradiol.
When your body presents low Testosterone levels, low amounts of Estradiol can also result, research shows, given that this hormone is derived directly from Testosterone (as we mentioned earlier in a process called aromatization).
Also, in parallel to what we discussed earlier related to measuring Testosterone levels, measuring Estradiol levels follow a similar path: ensure to check into how you look, feel and function to support the numerical ranges.
According to Endocrine Society, adult men have total Estradiol averages of 10-40 pg/mL (1.0 - 4.0 ng/dL), for what is considered normal value ranges.
Falling outside the immediate range doesn’t necessarily mean it’s a problem if you are not experiencing symptoms, but we’ll be breaking down what low and high amounts of estradiol looks like in your body so you can make sure you are optimizing your hormonal health and wellness.
Low Estrogen/Estradiol
Symptoms like fatigue, excess fat around your waist and belly, bone loss, lack of sex drive, anxiety, irratibility, and depression are typically all fair game when your body is not producing enough Estrogen. However, the majority of these symptoms can overlap with low Testosterone too, primarily because your body is hormonally imbalanced. We’ll repeat it again: it’s vital to maintain an optimized ratio of Testosterone and Estrogen for male health.
When your body is producing too much Estrogen, symptoms can appear similar to what shows in low amounts, around weight and sexual function, and cognitive functioning + behavior. Belly fat, erectile dysfunction, mood swings, anxiety and depression are typical symptoms of high Estrogen. As well, enlarged breasts, insomnia, sweating and night sweats can appear. Given that Testosterone and Estrogen are linked to metabolism, excess body fat produces higher Estrogen levels.
Ratios are still important here, so if Testosterone Replacement Therapy is being administered improperly, the body can be turning excess Testosterone into excess Estrogen. Know that stress, obesity and certain tumors are most commonly associated as precursors to high Estrogen levels.
Stress and obesity are very connected in the world we live in today - weight gain as response to high-stress environments is a vicious cycle and a harbinger of emasculated men. Hence, why lifestyle and healthy behaviors including diet and exercise (more to be shared later on this too) is key to hormonal balance and levels, as well as overall health.
What is Calcium D-Glucarate & Estrogen
Produced naturally by all mammals (including humans), Calcium D-Glucarate (CDG) is a natural substance produced in the body and also found mainly in fruits and vegetables. There’s research to support that supplementation of CDG has clinical significance to regulate Estrogen levels and metabolism.
Considered as a detoxification booster, CDG also has proven qualities to prevent certain types of cancer, research shows, promote antioxidant + reduce free radical damage, and what’s important here, aid in hormonal balance through removing excess Estrogen.
How does it work? An imbalanced gut can cause higher amounts of an enzyme called beta-glucuronidase to circulate, which results in increased estrogen levels (that would have been excreted from the body in its natural detox phase). Calcium D-Glucarate prevents beta-glucuronidase from disturbing your body’s detox system and aids in removing toxins out of your body, research shows.
Our recommendation for taking Calcium D-Glucarate: Take 1000mg or 1 gram before bed, or two 500 mg capsules. As with anything, make sure to consult with your doctor before taking supplements.
Now back to Testosterone.
What does optimized Testosterone do to the body?
It’s no wonder what Testosterone optimization can do to improve the male mind and body. We’re capturing below some of the evidence-based major benefits to optimized Testosterone.
Understand this and especially as we dive into the health behaviors: there’s no one action or silver bullet that will magically restore your Testosterone levels. It’s a combination of lifestyle hacks and behaviors that creates the conditions for your levels to increase. Increase your levels and you optimize your masculinity. You hold the power to do this and see to the benefits and changes to your life.
Body & Weight
One important clinical effect of optimized Testosterone is around weight-loss. In recent bodies of clinical research, there’s solid evidence that Testosterone therapy (or natural increases in Testosterone production) supports lean body mass, reduces fat and promotes weight-loss. It’s an inverse relationship, meaning the more pounds you shed, your body will produce more Testosterone. Men with obesity and who are at risk for or have Type II Diabetes are shown to be Testosterone deficient. Testosterone supports weight-loss by increasing your metabolism (burn calories at rest) and insulin sensitivity.
Most notably, Testosterone has a strong impact on muscle mass and growth. If you Google search Testosterone, you’ll see the most prominent image depictions associated with muscular, strong men. It’s been long known that Testosterone has a positive impact on putting on more muscle. As you increase Testosterone levels, it aids in the production of muscle protein synthesis and growth. Connected to its impact on weight-loss, Testosterone promotes lean body mass and muscle production, however it’s important to note that it’s supplemented by lifestyle, strength-training + exercise and diet. We’ll be talking later about all of these health behaviors as a major contributor to bulking and weight-loss.
Body & Weight
Sex Drive & Morning Wood
It’s widely known of the close association between Testosterone and libido: and it’s true, optimized Testosterone not only supports an increased desire for sex, but can improve mild erectile dysfunction (ED). The key here too is remembering it’s at optimal levels. Maintaining Testosterone in the ranges that are optimal will support consistent sex drive and rock-hard morning wood as you get older.
Sex Drive & Morning Wood
Behavior
What kind of a man do you want to be out in the world? What’s your calling?
Optimizing your Testosterone levels has an effect on dominance and status; ever wondered why some men seem to naturally or efforteselly assert themselves? Yes, and let this be clear, this is not a claim to be an asshole, rather to illuminate non-aggressive dominance as an effect of optimized Testosterone.
Risky, eh? Yes, optimized Testosterone is positively associated with risk taking, study shows (and for both sexes, men and women). Consider, though, that risk-taking does not mean to be detrimental. It absolutely can be, but we believe that healthy risk taking is a component of a healthy and successful man. Risk taking can lead to reward and success, but with appropriate caveats.
Mind
Probably one of the lesser known benefits of Testosterone is its impact on the brain related to psychological and cognitive health. Low T production has been shown to have an impact on mood swings, irritability, depression, stress, and anxiety. Promoting Testosterone has a clinically significant influence on memory, cognitive performance, positivity + mood, energy, and combating depression, research shows. According to the study, “in hypogonadal men, there is a significant decrease in many cognitive functions, such as episodic memory, working memory, processing speed, visual spatial processing, and executive function, which are regulated by the androgen receptor-regulated regions of the brain.”
That brain fog you experience? Promoting Testosterone can support mitigating this alongside other cognitive functioning benefits. As the study reflects among others, increasing Testosterone levels has been shown to improve spatial + verbal memory in older men.
In connection to this too, men with optimal levels of Testosterone have a lower risk of Alzheimer’s disease.
We’ll talk more about dopamine fasting to support optimization later, but in relation to physiological and brain benefits, Testosterone has a positive effect on boosting dopamine production in the brain. We know that dopamine is the “feel-good” hormone that supports reward, pleasure, and motivation. Increasing the production of this neurotransmitter contributes to feelings of motivation, happiness and reward.
What’s also a huge benefit to optimizing Testosterone levels is it’s connection to inhibiting stress and anxiety levels. Cortisol - a hormone that plays a key part in the body’s stress response - and Testosterone also have an inverse relationship. As your body pumps cortisol in response to stress, it blocks the production of Testosterone. So in turn, as Testosterone increases, it inhibits the activity for cortisol to be produced in the hypothalamic-pituitary-adrenal axis (HPA), the main pathway in the stress response cycle.
Like how health behaviors support weight-loss and muscle production, isolating Testosterone production solely as enough for cognitive and psychological health is not the end all, be all solution. It’s important to recognize, though, that deficiency of Testosterone is definitely connected to stress, anxiety, depression and other emotional + mental health imbalances.
Mind
Heart & Anti-Inflammation
Though it’s been historically demonized for having a negative impact on cardiovascular health, this study from the Journal of Clinical Endocrinology and Metabolism determines how low Testosterone is connected to a higher risk of death from heart disease and other cardiovascular complications. There’s further research that indicates how optimizing Testosterone improves overall metabolic profile. Connected to heart health, increased Testosterone is also correlated with supporting anti-inflammation in the body. We’ll chat more in-depth about also living an anti-inflammatory lifestyle, as this will directly support not just heart health and anti-inflammation but all other areas of healthy mind and body.
Heart & Anti-Inflammation
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