What is Testosterone?
There are some words that tend to carry more weight than they should. Testosterone is definitely one of them. It gets tossed around in gyms, shouted through fitness adverts, and whispered in conversations about ageing or energy levels. It is often tied to ideas about strength, drive or dominance, sometimes even used as shorthand for stereotypical male behaviour.
But for all the noise around it, testosterone is rarely talked about with much depth. Most people know it exists, that it has something to do with men, maybe with muscles, but beyond that, things start to get a little vague. And when we don’t really understand something, it becomes easy to oversimplify it, or worse, misinterpret it entirely.
The truth is, testosterone is not just for men. It is not just about sex or strength either. It is a hormone with a broad, essential role in human biology affecting everything from mood to metabolism to how well we sleep at night. It operates quietly behind the scenes, doing far more than most people realise.
So, let’s pause the hype for a moment. Let’s set aside the overpromises of “boosting” and “hacking” your hormone levels and instead take a grounded look at what testosterone really is, what it actually does, and why it matters for both men and women.
What is Testosterone?
Testosterone is often treated like a shortcut to power or masculinity, but when you strip back the marketing and myths, what you are left with is a hormone. A crucial one, yes, but still just a chemical messenger doing its job within a much larger system.
Scientifically speaking, testosterone belongs to a group of hormones known as androgens. These are often labelled male sex hormones, though that label is more convenient than accurate. Everyone produces and uses testosterone. just at different levels and for slightly different purposes. Men typically have more of it, but women need it too.
In men, the majority of testosterone is produced in the testes. In women, it comes from the ovaries and adrenal glands, though in smaller amounts. What it does depends on a range of factors including age, genetics, and overall health.Its impact starts early. During foetal development, testosterone is what helps form male reproductive organs. Later, during puberty, it is responsible for all the expected changes: a deeper voice, body hair, growth spurts, and increased muscle mass. But its role doesn’t stop at adolescence. Far from it.
Read more: What Happes When Men Have Low Testosterone?
Testosterone continues to contribute to a variety of functions throughout adulthood. Among them:
- Supporting the maintenance and growth of muscle and bone
- Regulating Puberty and sexual function
- Influencing sperm production in men
- Playing a part in energy levels and mood
- Helping with fat distribution and red blood cell production
The Role of Testosterone Across the Lifespan
Infancy and Childhood
Testosterone levels are relatively low during infancy and childhood. However, in male infants, there's a temporary surge in testosterone shortly after birth, which plays a role in the development of the male reproductive system.
During childhood, testosterone levels remain low until the onset of puberty
Puberty
Puberty marks a significant increase in testosterone production, especially in males. This surge leads to the development of secondary sexual characteristics, including:
- Deepening of the voice
- Growth of facial and body hair
- Increase in muscle mass and strength
- Growth of the testes and penis
In females, puberty also brings about a rise in testosterone, albeit to a lesser extent, contributing to muscle development and libido.
Adulthood
In adult males, testosterone levels stabilise but begin to decline gradually after the age of 30, decreasing by about 1% per year. This decline can lead to changes in body composition, mood, and sexual function.
In females, testosterone levels also decrease with age, particularly after menopause, affecting bone density, muscle mass, and sexual desire.
Older Age
As individuals age, the decline in testosterone can become more pronounced, leading to symptoms such as:
- Reduced libido and sexual function
- Decreased muscle mass and strength
- Increased body fat
- Mood disturbances, including depression and irritability
- Cognitive decline
It's essential to distinguish between normal age-related declines and clinically significant low testosterone levels, which may require medical intervention.
Factors Influencing Testosterone Levels
Testosterone is not immune to the push and pull of everyday life. It responds to how we live, what we eat, how we sleep, and even how we cope with stress. While it’s true that age and genetics play a role in determining your baseline hormone levels, a surprising amount of influence lies in your day-to-day habits.
Some of these influences are obvious, others are much more subtle. And often, it’s a combination of small things, building up over time, that begin to shift testosterone levels in one direction or the other.
For example, modern lifestyles tend to lean heavily towards convenience, but convenience does not always align with hormonal health.
A diet high in processed foods, poor-quality sleep, chronic stress, and lack of exercise, all of these things can gradually suppress testosterone. On the flip side, consistent movement, nourishing food, and proper rest create a healthier hormonal environment.
Let's break down the major influencing factors:
- Diet: Nutrients like zinc, vitamin D, and healthy fats (from sources like nuts, seeds, oily fish, and avocados) are essential for testosterone production. Diets high in sugar, overly processed meals, or lacking in key vitamins and minerals may slowly reduce testosterone over time
- Exercise: Regular physical activity, particularly resistance or weight training, has a well-established link to increased testosterone levels. Not only does exercise stimulate production, it helps regulate fat levels and metabolic health, both of which support hormonal balance
- Sleep: Testosterone is largely produced during deep sleep. Men who consistently get less than six hours of sleep tend to have significantly lower levels. The quality of sleep matters just as much as the quantity. Interrupted sleep patterns whether due to stress, shift work, or devices can interfere with this essential recovery time
- Stress: When you're under prolonged stress, your body produces more cortisol. This stress hormone competes with testosterone and can effectively suppress its production. Over time, ongoing stress can lead to a noticeable decline in testosterone levels
- Body composition: Excess fat, especially around the midsection, is one of the clearest lifestyle-related markers of low testosterone. Fat cells convert testosterone into oestrogen, so more fat often equals less testosterone, creating a feedback loop that’s difficult to break without lifestyle changes
- Environmental exposure: Chemicals known as endocrine disruptors, found in some plastics, cleaning products, and personal care items, may mimic or interfere with natural hormone function. Even though their effects are often slow and subtle, consistent exposure may influence hormone regulation over time
While it might feel overwhelming at first, the good news is that many of these factors are within our control. Simple but consistent choices such as reducing processed foods, making time for physical activity, or cutting down screen time before bed can all make a difference.
You don’t have to overhaul your entire lifestyle overnight, but small shifts add up. When it comes to hormones like testosterone, the body tends to reward patience and consistency over shortcuts or extremes.
Recognising and Addressing Low Testosteron
Low testosterone doesn’t always announce itself loudly. In fact, the early signs can be so gradual or seemingly unrelated that many people don’t realise what’s happening until symptoms begin to interfere with everyday life. The tricky thing is that these symptoms: fatigue, reduced libido, trouble concentrating can often be attributed to stress, poor sleep, or simply getting older. That’s why recognising the pattern is so important. It’s not about ticking one box, but noticing a cluster of signs that might point to an underlying issue.
It’s worth noting that low testosterone, or hypogonadism, affects both men and women, though it tends to present differently. For men, the conversation around testosterone is more prominent, but in women, too, a deficiency can quietly affect quality of life. Regardless of gender, low testosterone can make people feel “off” in a way that’s hard to describe but very real.
Some of the most commonly reported signs include:
- Reduced sex drive: One of the first and most obvious signs. A noticeable drop in libido that persists over time could be related to declining testosterone levels. In men, this may also be paired with erectile difficulties
- Low energy or persistent fatigue: This goes beyond just feeling tired after a long day. People with low testosterone often report feeling drained even after a full night’s sleep, with less stamina throughout the day
- Mood changes: Testosterone plays a role in regulating mood. Low levels may contribute to symptoms of depression, irritability, or anxiety. This can affect not just how someone feels, but also how they relate to others
- Loss of muscle mass and strength: A gradual decline in lean muscle can be a physical marker of low testosterone. Some people also find it harder to build or maintain strength despite regular workouts
- Increased body fat: Particularly around the abdomen. This change in body composition can sometimes feel frustrating, especially when combined with loss of muscle tone
- Difficulty concentrating or brain fog: Trouble focusing, memory lapses, or a general sense of mental fatigue can all be signs that hormone levels are off balance
If several of these symptoms sound familiar and persist over time, it may be worth getting tested. Testosterone levels can be checked through a simple blood test, typically taken in the morning when levels are naturally highest. If levels are low, your doctor may suggest retesting to confirm the results, since temporary dips can occur due to illness, stress or disrupted sleep.
If confirmed, the approach to treatment varies. In mild cases, improving sleep, diet and exercise might be enough to bring levels back to a healthier range. Some individuals benefit from increasing their intake of specific nutrients like vitamin D or zinc and reducing stress. However, when symptoms are more pronounced or persist despite these changes, testosterone replacement therapy (TRT) might be considered.
TRT is not a quick fix, and it’s not for everyone. It requires regular monitoring, as well as a discussion of potential risks such as increased red blood cell count, fertility changes, or prostate-related concerns in men. That said, when properly managed, many people find their energy improves, mood stabilises, and overall quality of life gets better.
Ultimately, recognising low testosterone is about being honest with yourself and tuned into how you feel. If something feels off, it’s worth asking questions even if they feel awkward at first. Because more often than not, those quiet warning signs are the body’s way of saying, “something needs attention.”
When the Background Matters More Than You Think
Testosterone is not always front of mind, and perhaps that’s part of the problem. Because when it works well, it works quietly. It supports sleep, mood, muscle, energy, sex drive, and countless other processes without demanding attention. But when it begins to falter. subtly, gradually, it can ripple through every part of life in ways that are hard to trace at first.
What makes testosterone tricky is that its effects are often mistaken for something else: burnout, ageing, laziness, stress. And while those things certainly exist, they can sometimes mask an underlying issue that deserves to be treated with the same seriousness as any other health concern.
It’s not about chasing youth or trying to force your body into some idealised version of masculinity or vitality. It’s about balance. A body that is hormonally balanced usually feels more stable, more responsive, more resilient. Whether that balance is supported through lifestyle shifts or, in some cases, medical help, the goal is the same, better quality of life, more clarity, and maybe just feeling like yourself again.
In a culture that often romanticises intensity and overlooks subtlety, testosterone reminds us that sometimes the quiet systems running in the background are the ones keeping everything else upright. And when something feels off, paying attention to those systems rather than brushing things aside can be a small but significant act of self-respect.
If there’s one takeaway, it might be this: testosterone isn’t everything, but when it’s out of sync, nothing quite feels right. And that’s worth listening to.
