Testosterone is nature’s gift to men. It's an extremely powerful hormone that is present in both genders, but particularly in men.
In this article, we shall take a look at the following areas:
- The big T
- Fueling humanity
- As a child
- Teenage years
- Middle age
- Low T
- The take away
The Big T
Testosterome has the ability to regulate men’s sperm production and control their sex drive.  This is obviously key to populating the human species but on an individual level, it's what can be a driving force in many things we do.
Testosteronic is also very important to our health, as it promotes the body to be anabolic, i.e. growth of muscle and it can also boost our energy levels amongst other benefits (you can read what testosterone is good for, here). 
As men age, their testosterone levels will naturally decrease, just as women’s sexual hormones do.  However, men’s sexual decline is not as rapid and not as sudden, but it’s effects are varied and sometimes devastating.
Before we go on to explore the various stages of testosterone decline, there’s another reason why testosterone is important. It fuels men’s competitiveness, aggression and other types of behaviors. 
If humanity didn’t have a competitive streak, would we be bothered about creating better and better things?
So when a man has low testosterone, his individual competitiveness goes down and that can mean many different things. It can result in not caring about winning or losing at sport, a fading ambition at work and also, being more of a pushover.  People might take advantage of you due to this personality change.
Therefore, it's incredibly important you understand what is happening to you or might happen to you due to naturally diminishing testosterone levels.
As a child
From the age of 1 to about 9 years old, boys will have a relatively stable testosterone level. It will be in the low range of the spectrum. It's normal for a child of about 9 years old to have 0.82 nmol/L of testosterone. 
Doctors may also measure a child’s testosterone in relation to the Tanner Staging process (also known as the Sexual Maturity Rating). This measures the child’s hormonal, physical and cognitive development as he gets closer to puberty by observing the scales of development for the external genitalia. 
A child with more energy than normal, may have a higher than normal testosterone level. Solutions to this have to be talked over with your doctor. Usually, testosterone at this age will stay low but it may begin to spike every now and then during the year. This is normal, his body is just getting ready to change, grow stronger, taller and heavier as he gets closer to sexual maturity.
Research demonstrates that Testosterone is also linked to behavior. There are strong associations with higher testosterone concentrations and fussy, frustrated behviors as well as unable to perform the desired actions. This can be linked to subsequent aggression. 
Here's some of these symptoms:
- There's plenty of energy to run around and play.
- Sex drive is pretty much non-existent.
- Erections are few and far between.
- Muscles are not developed but they still tend to heal pretty quickly.
As a teenager
During puberty, boys' average testosterone levels are 16.5 nmol/L.  Their testosterone levels will slowly begin to rise as they reach nearer to sexual maturity. It's important to their health that they are informed of the changes that will be occurring to their bodies and their behavior.
For one thing, their muscles will begin to become longer, larger and thicker as they enter into a normal anabolic mode. 
Testosterone shows signs of increasing in a teenager’s body as he becomes more sexually aware of himself. Testosterone will play a role in hair growth around the body, growing larger and thicker bones and also increasing sex drive.  It's completely normal for a boy to become more aware of his sexual organs and his sexual tendencies at this level.
If testosterone levels are high, this can create an advantage for those involved in sports and athletics. Testosterone stimulate muscle mass and reduces fat mass, androgens can also have effects in the brain to stimulate motivation for competitive events. 
Some typical symptoms are as folows:
- High energy levels. Doing sports, playing, and extra activities will be normal.
- Sex drive is slowly rising. Whilst not fully understood, the body's natural push to reproduce is growing.
- Muscles are still developing, but they are able to take a good amount of stress.
- Moods will generally be good, happy and positive.
At 18 or 19 years old, men will produce on average 15.4 nmol/L of testosterone, which is considered the peak. 
However the biggest change is, they will produce this level more frequently. This increased level of testosterone will help grow larger muscles that can handle stressful loads, heal quicker and have more explosive speed and strength. 
Their aggression levels can also be higher at this level, which could help in many ways. Their competitiveness will also be quite high, as they also go through societal changes.
They can vote, drive, drink and work to earn their own money. Being competitive and aggressive helps to chase their ambition but also, make their own life away from home. It's also common for men at this age to wake up with an erection.
Also at this stage, men will have a healthy sex drive. However, some men will also show signs of a receding hairline. If their family has a history of baldness or hair loss it's about 18-20 years old when a man might begin to show signs of his own hair loss.
Usually, this is because his testosterone is blocking proteins that grow hair. It's not because he has low testosterone or too high testosterone. His testosterone will be affecting Dihydrotestosterone (DHT) which is used by hair follicles. It's up to five times more potent and it's interference with normal hair growth is what makes you bald. 
The symptoms below are associated with earlyadulthood:
- Your muscles feel great. Powerful, strong and explosive, testosterone helps to promote muscle gain and healing.
- Producing a lot of testosterone comes with a few perks. Not only will you get an erection easily, you’ll be able to maintain it for quite a long time.
- You’ll have a morning erection pretty much every single day.
- Plenty of energy throughout the day. Testosterone promotes the production of energy, so when you have plenty of it, you’ll be able to get up early, workout, work for 8+ hours, walk the dog, make dinner and still have enough energy to have intercourse.
- You’re also more positive, with fewer days of depression throughout the year.
- Your sex drive is quite high. You’ll be more ballsy in talking to the opposite sex, you will last longer in the bedroom and you’ll probably want to have intercourse with a few members of the opposite sex a month.
As men get older, their testosterone levels may decrease. If they peak around 15.4 nmol/L at 19 years, they tend to have dropped to 13 nmol/L by the time they hit 40.  It may not seem much by reading it, but at this stage, men will show signs of ‘slowing down’ in many areas.
Middle-aged men might have a sex drive that is cut in half of more.  Their muscles may take longer to heal and they’re not as powerful as before. Explosive speed and strength is also going to decline.
At this stage a man in his 30's-40's may also begin to lose hair quite regularly and may even be bald by the time they're 50. Testosterone is crucial for men’s competitiveness, so career goals may take a back seat or becoming less competitive at a particular activity; such as sport.
Some of these signs may becoe more apparant:
- Some days you have lots of energy, some days you struggle. Your energy levels will begin to decline and become less predictable
- You might also begin to lose hair on your head, even if you don’t have male pattern baldness.
- Muscle growth and repair is slower, although if you workout still, this may be felt less than usual.
- Getting erections is hit and miss. Sometimes you feel perfectly normal, other times it's a battle to get an erection. You might have trouble maintaining it once you get it also.
It's about when you’re 60 and over when men show signs of an aging lion. Their sex drive is quite low and they don’t try as hard anymore to gain the attention of favor of the opposite sex. Regarding ambition and competitiveness, it's almost shot. They are in their retirement years and they might not have any reason to remain in the workforce anymore unless they need to.
Men’s testosterone levels at 40+ can range from as little as 6.46 nmol/L with testosterone levels significantly declining with advancing age.  However, just because they might have sex drive doesn’t mean they are capable of acting on it.
Their bodies are weaker and it takes a lot longer for muscles to heal from injury. Testosterone is still important as it keeps the flame of being male alive. Older men might still get the odd spontaneous erection but it's few and far between.
Common symptoms include:
- Feeling low on energy. Feeling lethargic just becomes normal. Why do you think old men walk slow and generally look like they’re moving in slow-motion?
- Having trouble getting an erection. No more morning erections is quite normal at this point.
- Hair loss over the body, not just the head. You might begin to lose hair on your face, arms, back, shoulders, chest, etc.
- Hair becomes thinner too. So even if it is still there, it becomes very weak.
- Gaining body fat is done easily and maintaining muscle mass becomes more difficult - elderly men need to eat more protein (1.2-2g per kg of bodyweight daily!) 
Testosterone dimsinishes with age, but this is considered normal, however, in some cases the reduction in testosterone is considered abnormal because it has taken such a hit.
Let's take a look at these two conditions.
As you might be wondering, this low level of testosterone is part of aging. Women have menopause, men have andropause. This is when the body starts to make less and less testosterone and also the sex hormone-binding globulin SHBG. 
This hormone pulls ‘usable’ testosterone from the body and begins to increase. In other words, your testosterone levels are lowering to the point where your body takes it from your sex drive to aid in mucle repair, producing energy, etc.
Andropause is natural, it's nothing to worry about. However, many men have a hard time getting used to themselves when they see their sex drive and competitive streak fading.
The following charcteristics could be a sure sign of andropause:
- Depression. Men who have lower levels of testosterone tend to suffer from feeling down, sad, gloomy and depressed. 
- Lack of energy. It can feel like you never have enough energy to end the day as you once did. You may begin to take more naps than before.
- Mood swings. Testosterone is what makes us men. We are confident, bold and we know and understand ourselves because of it. When our levels decrease, we might not feel ourselves and therefore are liable to abnormal mood changes.
- Difficulty in erections. Perhaps the most visible trait of andropause is having trouble getting an erection. Even if you do get it, it's not as strong as it once was and can go limp without warning. If you’re engaging in intercourse as long as you used to, it can also go limp because it doesn’t have the endurance anymore.
- Loss of muscle and strength. Perhaps the most annoying thing for most men is their lack of strength. Getting erections is nice when you need to, but not being able to lift, push and pull as much as you used to is incredibly annoying.
- Getting fat. As you can imagine, no longer having the energy or the strength to workout will mean, your BMI shoots up. Getting fat is quite normal when you have andropause but taking off the pounds becomes hard. 
Male hypogonadism on the other hand, is not due to age and is not normal. It's a testosterone deficiency and it is due to a physical failure of the testes.  The testicles are no longer producing testosterone or sperm at the normal rate they should. This can affect men as young as 18 and old as 70+.
The testicles have a disorder and possibly a disease that goes after the hypothalamus as well as the pituitary gland. Since it's a medical issue that requires physical inspection, you should go to your doctor to get a diagnosis if you do feel you have low testosterone when you shouldn't.
There are so many impacts hypogonadism can have on your life.
If you’re young it can mean.
- You have a slowed sexual development. Having trouble getting through puberty is stressful enough for many people, so when you are affected by this condition, it can be even harder.
- You may also have Gynecomastia due to fat building up in the body and a hormonal imbalance.
- Perhaps the most visible thing is, smaller testicles than normal. Having much smaller testes is quite alarming to many men, understandably so.
If you are an adult, hypogonadism might mean.
- You have a very low sperm count. This can mean you have trouble producing enough sperm to have children.
- Depression is your normal mood. When you are down all the time and don’t know why so many things affect you, it could be due to this or erectile dysfunction. 
- You also just feel low on energy.
- Your normal sleeping patterns are shifted.
- Your sex drive is almost non-existent. You have trouble getting sexually stimulated the normal way men do.
- The loss of body hair is also a clear sign you may have this condition.
- Weight gain is also something you could have.
- A clear loss of muscle as your body becomes gripped by muscle atrophy.
- Having trouble getting an erection.
The take away
So what should you take away from all of this information?
The key to having a rich full life with good stable testosterone levels is to do the following things.
Workout! Exercise is perhaps the best and most natural way for you to increase your testosterone levels. Do whatever you can. Workout at home, at the gym or just go for a run every other day. If you can, concentrate on the compound lifts such as squats.
Ensure that you get enough sleep, an adult needs about 7-8 hours of good quality sleep every day. Having too much can be as bad as having too little.
If you sense something is strange, make a note of it and see if it continues on for a couple of weeks. If it does, go speak to your doctor.
Talk about testosterone with your friends. Swapping stories and tips about maintaining a healthy level is really helpful.
If you’d like to know how we can help you boost your testosterone levels in a natural and sustainable way without the side effects associated with TRT, take a look at our product.
You can also contact us via email firstname.lastname@example.org.
This post was written by Ben - BA(Hons), PGCert Sport & Exercise Nutrition.
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