Written by Dr Max Draper
Testosterone has become a widely discussed topic in recent years. You may have seen it mentioned in the media, on social platforms, or even in conversations with friends. Some describe testosterone replacement therapy (TRT) as life-changing, while others warn against it. This can make it difficult to know what to believe.
In reality, testosterone is simply a hormone – and like any hormone, having too little (or too much) can affect how the body functions. This article aims to give you a clear, balanced understanding of low testosterone: what it is, how it presents, and what can be done about it.
What is testosterone, and why does it matter?
Testosterone is a hormone primarily produced in the testicles in men, and in smaller amounts in the ovaries and adrenal glands in women. Although often associated with muscle and libido, its role is much broader.
It affects:
- Energy levels
- Mood and mental clarity
- Muscle mass and strength
- Bone density
- Fat distribution
- Red blood cell production
- Sexual function and fertility
Because testosterone has receptors throughout the body, low levels can impact both physical and mental well-being.
What is low testosterone?
Low testosterone (also called hypogonadism) occurs when the body does not produce enough testosterone to meet its needs.
This can happen for a number of reasons:
- Problems with the testicles (primary hypogonadism)
- Issues with the brain signals that control hormone production (secondary hypogonadism)
- Age-related decline
- Chronic illness or metabolic issues
It is important to understand that testosterone levels naturally vary between individuals. A “low” level is not just about a number on a blood test – it must be interpreted alongside symptoms.
Common symptoms
Low testosterone can affect multiple areas of life. Symptoms often develop gradually and may be mistaken for stress, ageing, or lifestyle factors.
Common symptoms include:
Physical symptoms
- Persistent fatigue
- Reduced muscle mass and strength
- Increased body fat
- Reduced exercise tolerance
- Aches and slower recovery
Psychological symptoms
- Low mood or depression
- Anxiety or irritability
- Brain fog or poor concentration
- Reduced motivation
Sexual symptoms
- Reduced libido
- Fewer morning erections
- Erectile difficulties
Not every person will experience all of these, but a combination of symptoms across different areas is often a key clue.
Causes and risk factors
There are several factors that can contribute to low testosterone:
- Obesity and metabolic health issues
- Chronic stress and poor sleep
- Sedentary lifestyle
- Excess alcohol intake
- Certain medications (e.g. long-term opioids, steroids)
- Underlying medical conditions (e.g. diabetes, thyroid disorders)
- Testicular damage or surgery
In some cases, there is no obvious cause.
From a clinical perspective, it’s important not to focus only on testosterone itself, but to look at the wider picture – including inflammation, body composition, and overall health.
How is it diagnosed?
If low testosterone is suspected, a healthcare professional will usually start with blood tests, but further tests beyond bloods maybe needed.
Diagnosis is based on a combination of:
- Symptoms
- Blood test results
- Medical history
It’s also important to rule out other conditions that can cause similar symptoms, such as thyroid disorders, anaemia, or mental health conditions.
Treatment and management options
- Lifestyle optimisation
Before considering medication, addressing lifestyle factors is essential. In some cases, this alone can significantly improve symptoms.
Lifestyle factors support not just testosterone levels, but overall hormonal health.
- Testosterone Replacement Therapy (TRT)
If a deficiency is confirmed and symptoms persist, TRT may be considered.
The aim of TRT is to restore testosterone to a healthy level and improve symptoms.
Common forms in the UK NHS include:
- Gels (applied daily to the skin)
- Injections (given at intervals, depending on the protocol)
Treatment should always be:
- Individualised
- Carefully monitored with regular blood tests
- Reviewed over time, as needs can change
TRT is not a quick fix or a lifestyle substitute. It works best when combined with good health habits.
Important considerations
Like any medical treatment, TRT has potential risks and considerations:
- It can reduce sperm production and affect fertility
- Blood markers (such as red blood cell count) need monitoring
- Dosing must be tailored to avoid side effects
A thorough discussion with a qualified clinician is essential before starting treatment.
Can low testosterone affect women?
Yes – although at much lower levels than men, testosterone also plays a role in women’s health.
In women, low testosterone may contribute to:
- Reduced libido
- Low energy
- Reduced sense of well-being
In the UK, testosterone may be prescribed in specific situations, particularly for women with low sexual desire after menopause, and always in carefully controlled doses.
When should you seek medical advice?
You should consider speaking to a healthcare professional if you experience:
- Ongoing fatigue or low energy
- Persistent low mood or anxiety
- Reduced libido or sexual function
- Difficulty building or maintaining muscle despite effort
These symptoms are common and can have multiple causes — but they are worth investigating.
A clinical perspective
My understanding of testosterone is shaped not only by clinical practice, but also by personal experience. I required TRT following treatment for testicular cancer, and like many patients, my symptoms were initially attributed to other causes.
Appropriate treatment helped restore my energy, clarity and overall quality of life – but it also highlighted how easily this condition can be overlooked.
Summary
Testosterone is a key hormone that affects far more than just physical strength or sexual function. Low levels can impact energy, mood, and long-term health.
If you’d like to explore this topic in more depth, including common myths and a practical approach to testing and treatment, I cover this in my book Testosterone Decoded.
Testosterone Decoded is a practical, accessible guide written for both the public and GPs, inspired by my own journey with low testosterone, and covering everything from symptoms and causes to diagnosis, self-care, treatment options, FAQs, and how to find the right provider.
References
- British Society for Sexual Medicine (BSSM) Guidelines on Adult Testosterone Deficiency
- National Institute for Health and Care Excellence (NICE) guidance on menopause and hormone therapy
- Wu FC et al. (2010). Identification of late-onset hypogonadism in middle-aged and elderly men. NEJM
- Corona G et al. (2011). Low testosterone and metabolic syndrome. Journal of Sexual Medicine
Dr Max Draper BM BS, MRCGP
GP with a specialist interest in hormone health and optimisation. Dr Draper works with patients to address the root causes of hormonal imbalance and improve long-term health outcomes.
Instagram: @dr_max_draper
Lead clinician at www.alphagenix.co.uk + www.my-atlas.co.uk
Read the first chapter of Dr Draper’s book ‘Testosterone Decoded’ and a variety of places to buy it.
Open until the end of July. Winners will be contacted directly.
Medical disclaimer
This content is for general information only and is not a substitute for professional medical advice. Always consult your GP or a qualified healthcare professional if you have any concerns about your health.