What Is Testosterone and Why Does It Matter?

Testosterone is the primary male sex hormone, produced mainly in the testes and regulated by the brain's hypothalamus and pituitary gland. While it's often discussed in the context of muscle and libido, testosterone plays a far broader role in men's health — influencing bone density, red blood cell production, mood, cognitive function, and energy levels.

Testosterone levels naturally peak in early adulthood and gradually decline with age, typically at a rate of about 1–2% per year after the age of 30. This is a normal part of aging, but certain lifestyle factors can accelerate this decline significantly.

Signs That Your Testosterone May Be Low

Low testosterone (clinically called hypogonadism) can manifest in a variety of ways. Common signs include:

  • Persistent fatigue and low energy, even after adequate sleep
  • Reduced libido or sexual desire
  • Difficulty maintaining or building muscle mass
  • Increased body fat, particularly around the abdomen
  • Mood changes, irritability, or low motivation
  • Difficulty concentrating or brain fog
  • Reduced bone density (may be detected through a DEXA scan)
  • Erectile dysfunction

Important: These symptoms can also be caused by many other health conditions. If you're experiencing several of these, speak with your family doctor about getting a blood test to measure your testosterone levels. In Canada, this is covered under provincial health plans when medically indicated.

What Affects Testosterone Levels?

A number of modifiable lifestyle factors have a meaningful impact on testosterone:

Factors That Lower Testosterone

  • Chronic stress: Elevated cortisol (the stress hormone) suppresses testosterone production.
  • Poor sleep: Most testosterone is produced during deep sleep. Consistently getting less than 7 hours can significantly reduce levels.
  • Excess body fat: Fat tissue — particularly visceral (belly) fat — converts testosterone into estrogen via a process called aromatization.
  • Sedentary lifestyle: Lack of physical activity, especially resistance training, is linked to lower testosterone.
  • Excessive alcohol: Regular heavy drinking impairs the glands responsible for testosterone production.
  • Nutritional deficiencies: Low zinc, vitamin D, and magnesium are all associated with reduced testosterone.

Factors That Support Healthy Testosterone

  • Strength training: Compound lifts like squats and deadlifts are among the most potent natural stimulants of testosterone.
  • Adequate sleep: Prioritizing 7–9 hours of quality sleep is one of the most impactful things you can do.
  • Healthy body weight: Losing excess body fat, particularly abdominal fat, consistently improves hormonal balance.
  • Stress management: Chronic stress reduction through exercise, mindfulness, or social connection matters.
  • Vitamin D: Many Canadians are deficient in vitamin D, especially in winter months — supplementation may support hormonal health.
  • Adequate dietary fat and cholesterol: Testosterone is synthesized from cholesterol. Very low-fat diets can impair hormone production.

When to See a Doctor

If lifestyle changes don't resolve your symptoms, or if your blood work confirms clinically low testosterone, a physician may discuss options such as testosterone replacement therapy (TRT). TRT is available in Canada through prescription and comes in various forms — gels, injections, and patches. It's not appropriate for everyone and carries risks, so this decision should always be made with a qualified healthcare provider.

Key Takeaways

  • Testosterone affects far more than just libido — it influences energy, mood, muscle, and cognition.
  • Lifestyle factors like sleep, exercise, stress, and body weight have a significant impact on levels.
  • If you suspect low testosterone, get a blood test through your doctor before assuming a problem.
  • Natural optimisation through lifestyle improvements is always the first step.