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What Causes Low Testosterone?

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Testosterone is the primary sex hormone that triggers masculinity. It takes full effect during puberty, turning adolescent boys into the men they grow up to be. Recent research revealed that almost a quarter of men over 30 suffer from low testosterone[1]. The symptoms aren’t pleasant and can seriously harm your health. But what causes low testosterone? We investigate the science behind this compromising condition.

Why is testosterone important?

Testosterone is arguably the most essential hormone a man has. Primarily produced in the testicles, it triggers masculine traits like sex drive, muscle mass, bone density, and facial hair during puberty.

But that doesn’t mean testosterone becomes obsolete in your twenties. On the contrary, it should thrive well into adulthood to keep your male characteristics healthy, strong, and prominent. Testosterone helps men to stay fit, muscular, sexually active, and mentally sharp[2]. So you could say it’s almost essential for living your best life.

Normal testosterone levels for men vary between 300 – 1,000 ng/dL. Where you sit can depend on factors like age and lifestyle. Women also produce testosterone. However, their natural levels are usually a lot lower.

Low testosterone in men

Testosterone should flow freely into adulthood before levelling out during your 30s. Experts say this is when your natural decline starts, at around 1% per year. Once testosterone levels fall below 300 ng/dL, they’re recognised as low.

Age-related testosterone reduction is a normal and inevitable process. But how you live your life can also contribute, with unhealthy habits holding back the hormone even more. Depending on your medical status, you could have a low testosterone-triggering disease. It’s not just older men who suffer. Some people struggle from birth.

In 2007, researchers saw a substantial drop in the testosterone levels of US men over a 27-year experiment[3]. This means that, unfortunately, our 21st-century testosterone levels don’t match up to previous generations.

What are the symptoms of low testosterone?

Low testosterone shows itself in lots of different ways. None of the symptoms are seen as positive and can happen at any stage of life. Like we said earlier, low testosterone isn’t just reserved for older men.

Symptoms of low testosterone include[4]:

  • Lagging energy levels
  • Low libido
  • Muscle loss
  • Body fat gain
  • Brain fog
  • Irritability
  • Impotence
  • Sexual performance issues
  • Hair loss
  • Decreased bone mass
  • Depression and low mood
  • Gynecomastia (large breasts in men)

Naturally, developing any of these symptoms can considerably impact your well-being. It could be that you experience a combination of them too. Low testosterone doesn’t just affect you physically but mentally as well.

What causes low testosterone?

Because of how integral testosterone is to your health, multiple things can change it. Some causes can be simple to solve, while others are full-blown medical conditions. Low testosterone is classed into two distinct categories; primary hypogonadism and secondary hypogonadism[5]. Hypogonadism is the proper medical term used to describe low testosterone.

Complications caused by underactive testes are known as primary hypogonadism. Men who suffer from this fail to make the proper amount of the hormone in them. However, issues triggered by the pituitary gland or hypothalamus create what’s known as secondary hypogonadism. This means the problem might not lie in the testes but inside the brain.

Here is a list of low testosterone causes and the categories they fit in:

1. Physical testicle injury

Class: Primary

When both testicles are injured, testosterone production can be affected. Their location away from the abdomen makes them prone to damage.

2. Hemochromatosis

Class: Primary

Excessive blood iron levels can trigger pituitary dysfunction and also cause your testicles failure.

3. Cancer treatment

Class: Primary

Chemotherapy and radiation therapy can negatively impact testosterone production. Although the effects might be reversed after the treatment, it’s not always the case.

4. Aging

Class: Primary

All of us get older, there’s nothing we can do to stop time. Age related decline happens to every man and how much is lost varies wildly [6]. Lifestyle factors can affect testosterone levels either positively or negatively. Luckily, age-related testosterone loss is reversible.


Class: Secondary

Contracting HIV/AIDS affects the pituitary, testes, and hypothalamus. One result from the interactions is low testosterone.

6. Obesity

Class: Secondary

Experts have found a clear connection between low testosterone and obesity. Being overweight and having low testosterone can exacerbate each other as well[7][8].

7. Stress

Class: Secondary

Chronic stress from life, excessive exercise, and prolonged dieting has been shown to cause hypogonadism too. According to some scientists, this is because of hiked-up levels of cortisol, the stress hormone[9]. Testosterone and cortisol simply cannot thrive together – when one goes up the other must come down.

It’s important to recognize that stress will mess with your diet too. Studies show that people who are stressed out often overeat, gain weight, and store more dangerous abdominal body fat[10]. Experts say that testosterone levels are frequently reduced in obese people[11].

8. Nutrition deficiencies

Class: Both

Being deficient in specific nutrients can halt or impede testosterone production. For example, zinc, magnesium, iron, vitamin D, cholesterol, boron, and a whole host of other nutrients contribute to keeping your masculine hormone healthy[12].

It’s easy to see how the modern man is susceptible to low testosterone. Sedentary lifestyles, stress, and processed food have a mainstay in our society.

How Do I Fix it?

Not all cases of low testosterone are passed for treatment. Depending on your symptoms, a doctor might recommend trying a lifestyle change first. So, how do you fix testosterone? What can you do to take matters into your own hands?

Your main option is to live in a healthy, testosterone-promoting way. Fixing your diet, exercising, and sleeping well are all pillars of well-balanced hormones. Adopting them into your lifestyle can set you up for testosterone success.

Here are a handful of ways you can try to fix your low testosterone:

1. Exercise regularly

Getting your blood pumping can be a great way to support T production. According to a study published in the European Journal of Applied Physiology, men who exercise regularly appear to have higher testosterone levels than sedentary types[13].

Essentially, working out in a routine seems to benefit your hormones. Obese people who exercise may boost their T more than weight loss alone [14]. So, if you’re obese, combining gym time with a diet might enhance your efforts.

… especially with weights and HIIT

But not all exercise is created equal – not when testosterone is concerned. Strength training and cardio are in a constant battle. Most people sit in one camp or the other, apart from cross-training athletes. Yet, when it comes to hormone balance, lifting heavy seems to pip jogging to the post, followed closely by intense HIIT-style sessions.

One study from 2007 saw that four weeks of resistance training (3 days p/w) boosted testosterone over the period and after each session[15]. Then, in 2014, another study suggested that HIIT workouts increased T in men[16].

The trick is to make sure you’re not overdoing it. Overtraining causes chronic stress, which we already know fuels hypogonadism. Monitor your rest, recovery, and RPE to check they’re not slipping.

2. Avoid endurance training

Chronic endurance cardio sessions seem to sever testosterone levels[17]. So, marathons and back-to-back hour-long bike rides aren’t recommended. If your testosterone levels are fine, and you have good recovery practices in place, then endurance training should be fine. But if you have low testosterone, it could be due to overtraining, with endurance training being the likely culprit.

3. Get more vitamin D

Vitamin D deficiency is rife among modern men. Experts even estimate that almost 50% of people worldwide don’t get enough[18]. According to one 12-month study, supplementing with 3,332 IU vitamin D3 every day helped deficient men boost their testosterone by 20%[19]. What’s also worth noting is that getting more sun can have a similar effect too[20].

Current evidence suggests that vitamin D might only boost testosterone in the case of deficiencies. If you already have thriving T and healthy vitamin D, you might not get any effect. Vitamin D is widely available as a standalone supplement and inside testosterone boosters.

4. Ashwagandha

Ashwagandha is an ancient therapeutic herb used for thousands of years[21]. Traditional cultures typically turn it into a medicine to treat stress and anxiety. Modern scientists add ashwagandha to the adaptogen class, which helps the body handle stress. Interestingly, studies show this adaptive quality makes it an excellent tool for boosting testosterone.

According to one of those studies, men who took five grams daily for three months boosted their testosterone by 10-22%. Their fertility also seemed to benefit because 14% of their partners also became pregnant [22]. Ashwagandha is widely available as a standalone supplement and inside testosterone boosters.

5. Try zinc

Zinc and testosterone share a very close relationship. They’re so connected that when researchers restricted zinc from healthy test subjects’ diets, they saw a drop in the hormone. The scientists were also able to quickly reverse the dip by handing out zinc supplements[23].

Like vitamin D, deficient men seem to benefit most from zinc supplementation. If your zinc levels are topped up and your testosterone is healthy, you might not have any results[24]. Zinc is widely available as a standalone supplement and inside testosterone boosters.

6. Reduce stress

Earlier, we looked at the health-damaging and testosterone-trampling effects of chronic stress. So, consistently high levels of cortisol are something to avoid. You can start by reducing the amount of stress in your life. Say no to a few more things, find time to unwind, and take control of how much pressure you pile on yourself.

Stress is undoubtedly no badge of honour when it’s ruining your hormone balance. Next, look at establishing a stress-free lifestyle. Eat a well-balanced diet low on processed sugar, get to the gym, burn off that negative energy, laugh a lot, and enjoy a great night’s sleep. Trust us; your testosterone will thank you for it.

7. Lose weight

It’s no myth that being overweight or obese exacerbates low testosterone[25]. Losing weight and living a healthy lifestyle could help rebalance your hormones. You can lose weight by increasing your protein intake, reducing your portion sizes, and removing junk food from the majority of your diet. Exercising regularly, sleeping better, and reducing stress can also help.

8. Sleep well

Scientists say there’s a clear connection between sleep quality and testosterone levels. In addition, research shows that taking sleep for granted affects younger and older men [26][27]. You can’t get away with sleep deprivation even if you’re otherwise young and healthy.

Set a routine to get seven to eight hours of sleep every night. Turn off bright lights, screens, and other electronic devices an hour before resting. Social media and Netflix will still be there in the morning, don’t worry.

What Causes Low Testosterone? Final Thoughts

Low testosterone can be caused by age, illness, and lifestyle. While you can’t change the first, your actions go a long way in altering the last two. The bottom line is to live a healthy, hormone-supporting lifestyle. Eat well, exercise regularly, hit the weight room, and chill out.

Your testosterone balance isn’t quite accustomed to the hectic lifestyles of 21st-century men. So it’s best to go back to basics and look after your health first. Doctors don’t always treat low testosterone. If they think there are easier changes to be made, you might not be given therapy right away. TRT’s long-term effects and safety aren’t currently known, so it isn’t always the go-to option.

Try the tips above and maybe add a testosterone-support supplement to your diet. Take action today and help your masculine hormone thrive. Read our tips on how to increase testosterone levels in men naturally!