A Quick Guide To Understanding Testosterone
In this article, we'll explore what testosterone is, its role in men and how it relates to our health, performance, and quality of life.
Testosterone is the primary androgenic hormone meaning it’s responsible for the development and maintenance of male-specific organs such as the testes, penis, and prostate, and masculine traits such as body hair, bone growth, muscle mass, tone of voice, etc.
Contrary to popular belief, women also produce testosterone in addition to estrogen, and here is the first myth debunked…women actually produce more testosterone than they do estrogen…but still much less than men. The role of testosterone is critically important for both men and women but is a key influencer of the many physiological and psychological factors that help males develop during adolescence and keep them healthy throughout their lifespan.
A Snapshot of Testosterone’s Role In Men’s Health
The development of the penis and testes
Influences body size and body mass
The deepening of the voice during puberty
The appearance of facial and pubic hair starting at puberty; later in life, it may play a role in balding
Muscle size and strength
Bone growth and strength
Sex drive (libido)
Psychological drive and motivation
Mood and emotional states
Sperm production
This list is only a few of the most obvious things that testosterone does in men. It could be argued that in reality, testosterone affects every aspect of physiology including:
Immunity
Recovery from illness and injury
Metabolic health
Blood sugar
Cardiovascular health
Brain and cognitive health.
In addition, testosterone has a huge influence on our mental and emotional state and can affect our mood, emotional resilience, relationships, motivation, success and performance in life, work, and athletics.
Where Testosterone Comes From
Let’s start at the very top of the production process, in the brain, and more specifically an area in the middle of your brain called the hypothalamus. The hypothalamus releases a hormone called gonadotropin releasing hormone or GnRH for short.
This acts on the pituitary gland just below the hypothalamus to produce two intermediary hormones called luteinizing hormone (LH), and follicle stimulating hormone (FSH), both of which target the testes.
While FSH induces the testes to produce sperm, LH causes the testes to produce testosterone. The vast majority of testosterone is produced in the testes…hence the name…but some can also be created indirectly by the adrenal glands…but since the testes are where the vast majority of it is produced in men, we’ll keep our focus here…our eye on the ball as it were…ok that was bad.
Once LH reaches the testes, the Leydig cells convert cholesterol from your bloodstream to a hormone called pregnenolone, which is considered the master sex hormone. Pregnenolone converts to dehydroepiandrosterone (DHEA), which further converts to androstenedione, and eventually to testosterone.
Simplified Testosterone Pathway:
(Hypothalamus) >> GnRH >> (Pituitary) >> LH >> (Testes) >> Pregnenolone >> DHEA >> Androstenedione >> Testosterone >> (Blood)
The circulatory system then delivers testosterone to the rest of the body. The level of testosterone in the blood is important for 2 reasons.
First: So many organs and tissues like the brain, bones, and muscles rely on a regular supply of testosterone to maintain health.
Second: The amount of testosterone circulating in the blood sends a signal to the hypothalamus in the brain to either increase or decrease the production of testosterone by the testes through a feedback loop. This feedback loop will become important when we talk about the causes of testosterone imbalance and the use of testosterone replacement therapy for both health and athletic enhancement.
I mention these pathways, not to bore you with physiology, but to show how even a straightforward process in the body has many steps where something can potentially go awry.
This is one of the things that makes hormone balancing potentially challenging, because if we focus too much on only one factor, and neglect to measure and address the others, we can create an even worse problem.
It’s also important to note that blood levels of testosterone do naturally fluctuate throughout the day because your testosterone pathways are more active during some parts of the day, and less active during others.
In addition there are other factors like exercise, stress, sleep, having sex, being around attractive women (yes it's a thing), and other influences that will cause your testosterone levels to fluctuate throughout the day as well. Don’t worry I’m dedicating a big section of this guide to discussing those factors.
But first, let’s talk about what happens to us when our T is too low for too long.
The Signs and Symptoms of Low Testosterone In Men
Let’s simplify the functional role of testosterone into 3 basic buckets:
1) growth & metabolism
2) mood & sex drive
3) immunity & recovery
This will help you put the following list of short-term and long-term deficiency symptoms into perspective. Chronically low testosterone can affect any of the three processes above which can affect many aspects of health in both the short and long term.
Short Term Symptoms
Short term signs and symptoms are mostly related to mood, energy, motivation, and sex drive fluctuations throughout the day. These include:
Low energy
Low motivation
Low libido
Reduced cognitive performance (attention and memory)
Moodiness and irritability
Feeling depressed and uninspired
Feeling easily overwhelmed and frustrated
Sleepiness during the day
Testosterone is linked to the brain hormone called dopamine (Dop). Dopamine levels and testosterone levels balance each other through a complex two-way biochemical dance. Since dopamine is the hormone most associated with motivation it makes sense that when testosterone levels decline, bringing dopamine down with it, then so will go your motivation, energy, and drive.
You can think of testosterone levels influencing how much dopamine can be produced by the brain, and how long it takes to recover dopamine levels once depleted…this isn’t exactly how it works but is close enough for now.
For example, the combination of high morning cortisol and high morning testosterone levels can improve drive and motivation by increasing baseline dopamine levels throughout the day.
Practices like early morning aerobic exercise and early morning direct sun exposure are two ways to optimize the testosterone, cortisol, and dopamine relationship.
Now, let's dive into what happens when your testosterone is too low for too long.
Long Term Signs and Symptoms
When your testosterone has been chronically low, especially for many years, the most common signs and symptoms include:
Chronic fatigue
Generalized weakness
Reduced body and facial hair
Loss of muscle mass
Low libido
Impotence
Small testicles
Reduced sperm count and infertility
Increased breast size (gynecomastia)
Cognitive deficits (attention, memory, and problem solving)
Brittle bones and an increased risk of fractures
Depressed immunity
Looking at the very depressing list above it’s clearly a description of what happens to men as they age…which if you’re 95, might make sense. The problem is that I see men like this who are in their 40s and 50s and have been struggling with undiagnosed low testosterone for many years. For some reason their medical providers don’t see early signs of aging like these to be overly problematic as long as they aren’t immediately life threatening.
So, a man continues his early decline into decrepitude simply because our medical system has a very broken definition of male health. If a doctor does think to measure a man’s testosterone level they will often use a test called Total Testosterone (Total T). This is a step in the right direction. The problem is that Total T, when used on its own, is not precise enough to really determine how healthy a man’s testosterone production is.
How to Assess Your Testosterone
Free Testosterone (Free T) and Sex Hormone Binding Globulin (SHBG) are two tests that are both easy to order and very inexpensive. A combination of Total T, Free T and SHBG can give a more complete snapshot of a man’s testicular function and testosterone production. Unfortunately most doctors don’t order these tests for their male patients which means that millions of men could be walking around thinking their testosterone is ok when it is really quite low.
This can really be a problem for a lot of men. Just think back to the list of signs and symptoms of low testosterone. If a man is walking around feeling weak, tired, getting fat, unmotivated to exercise, low libido, etc. and their doctor says “well your testosterone levels look fine to me,” that man could feel a bit hopeless not knowing something more could be done…easily…and cheaply. I talk with guys like this all the time in my consulting practice.
The good news is if you’re experiencing those symptoms and you have a complete testicular function test showing low functional testosterone levels, you have a whole new set of options to pursue to improve your health and quality of life.
We'll be doing a much deeper dive into specific ways you can assess your own testosterone levels in a later article so be sure to subscribe so you don't miss out.
For more information about specific lab tests, I have a Men’s Health Cheatsheet that you can download for free that outlines all the lab values for optimum health, along with other handy resources.
Now that you have a basic understanding of:
What testosterone does
How it’s made
What can happen when it's low
We're going to explore exactly what causes low testosterone in men in the next article so again...be sure to subscribe and stay tuned!
Yours in health,
Joshua Graner MS, IFMCP
Men's Health And Performance Specialist