Low Testosterone Symptoms in Men: Signs, Risks and Treatment Options

Fatigue that won't shift, a libido that's gone quiet, or muscle that seems to disappear no matter how often you train - these kinds of changes can be easy to write off as stress or just getting older. But for some men, they point to something more specific: low testosterone.

Testosterone levels decline naturally with age, dropping roughly 1% per year from your mid-thirties onwards. For most men, this gradual change causes no obvious problems. For others, levels fall low enough to affect quality of life in real, measurable ways.

Here's what the symptoms actually look like, what counts as clinically low, and what your options are if you suspect your levels have dropped.

What testosterone does in the body#

Testosterone is the primary male sex hormone, produced mainly in the testicles with small contributions from the adrenal glands. The brain regulates production through a feedback loop involving the hypothalamus and pituitary gland, adjusting output based on circulating levels.

It does far more than drive sex drive. Testosterone influences:

• Muscle mass and strength
• Bone density
• Red blood cell production
• Mood and mental sharpness
• Fat distribution
• Body and facial hair
• Energy levels and sleep quality

In many tissues, testosterone converts into either dihydrotestosterone (DHT) or oestradiol, which explains why its effects reach so far beyond sexual function. When levels drop significantly, the effects can be wide-ranging and sometimes confusing to pin down.

The symptoms of low testosterone#

The tricky thing about low testosterone is that its symptoms overlap with dozens of other conditions. Stress, poor sleep, depression, thyroid problems and plain old ageing can all produce similar effects. That's why a blood test matters rather than relying on symptoms alone.

That said, certain symptoms are particularly associated with testosterone deficiency, and recognising the pattern is a useful first step.

Low sex drive#

Reduced libido is one of the most consistently reported symptoms of testosterone deficiency, affecting an estimated 50-70% of men with clinically low levels. It often develops so gradually that men don't notice until it's been a problem for months or years. If your interest in sex has noticeably declined compared to your normal baseline, it's worth paying attention to.

Erectile dysfunction#

Testosterone isn't the only factor in getting and maintaining erections - blood flow, nerve function and psychological state all play roles - but low levels can contribute to erectile difficulties. Some men with testosterone deficiency experience reduced morning erections or find it harder to maintain an erection during sex. If erectile dysfunction is your primary concern, it's worth exploring whether it has a hormonal, vascular, or psychological cause (often it's a combination). Totiva offers erectile dysfunction treatments including sildenafil and tadalafil, which work regardless of underlying testosterone status.

Fatigue and low energy#

This isn't ordinary tiredness. Men with low testosterone often describe a persistent flatness - a lack of drive and physical energy that sleep doesn't fix. Research published in the Journal of Clinical Endocrinology and Metabolism found significant associations between testosterone deficiency and fatigue, with improvements reported following treatment. If you're sleeping adequately but still feel constantly drained, that's a meaningful symptom.

Loss of muscle and strength#

Testosterone is central to muscle protein synthesis. When levels drop, maintaining muscle becomes harder even with consistent training, and strength can decline noticeably. This is often accompanied by a shift in body composition.

Increased body fat#

Particularly around the abdomen, weight gain is a common feature of testosterone deficiency. The relationship goes both ways - excess body fat (especially visceral fat) reduces testosterone levels by increasing conversion of testosterone to oestrogen, creating a cycle that's difficult to break without addressing both sides. Obesity and type 2 diabetes are both risk factors for hypogonadism, and men with these conditions are more likely to be affected.

Mood changes and low mood#

Irritability, low mood, reduced motivation, and difficulty concentrating are all reported by men with testosterone deficiency. The link between testosterone and mental health is increasingly recognised. Some research suggests that men with low testosterone are at significantly higher risk of depression. This doesn't mean low testosterone causes depression in all cases, but the overlap is real and worth considering if you've noticed a change in your mental wellbeing.

Reduced facial and body hair#

Hair growth depends partly on testosterone and its conversion to DHT. A reduction in beard growth, body hair thinning, or loss of pubic hair can be a sign of hormonal changes, though this symptom is less specific than others.

Night sweats and hot flushes#

Less commonly discussed but genuine symptoms, hot flushes and night sweats do occur in men with testosterone deficiency - similar to the vasomotor symptoms experienced during the female menopause. These are often dismissed or attributed to other causes, but they're worth mentioning to a clinician.

Could something else be causing your symptoms?#

Honestly, yes - quite possibly. Many of the symptoms above have other explanations that deserve consideration:

• Sleep apnoea causes profound fatigue and is strongly associated with low testosterone (and also suppresses it further)
• Hypothyroidism produces fatigue, low mood, weight gain and reduced libido
• Depression accounts for low energy, poor concentration, and reduced sex drive
• Cardiovascular disease underlies many cases of erectile dysfunction, particularly in men over 40
• Chronic stress suppresses testosterone production through cortisol
• Medication side effects - antidepressants, opioids, and some blood pressure medications can all affect testosterone and sexual function

A good clinician won't just check your testosterone. They'll consider the full picture. The NHS recommends your GP assess both physical and psychological factors before attributing symptoms to hormonal causes.

What counts as low testosterone#

Testosterone levels are measured through a blood test, ideally taken in the morning (before 11am) when levels are naturally at their peak. Both total testosterone and, where relevant, free testosterone (the biologically active fraction) can be measured.

The British Society for Sexual Medicine (BSSM) guidelines use a total testosterone threshold of below 12 nmol/L as a starting point for investigating deficiency, though clinical decisions also take symptoms into account. It's not purely about the number.

Levels between 8 and 12 nmol/L are considered borderline, and treatment decisions in this range depend on the presence and severity of symptoms. Below 8 nmol/L is generally considered clearly deficient. Above 12 nmol/L, testosterone deficiency is unlikely to be the primary cause of symptoms.

Two blood tests on separate occasions are typically required before a diagnosis is confirmed, as testosterone levels can fluctuate day to day.

Who gets low testosterone and when#

Late-onset hypogonadism (the clinical term for age-related testosterone deficiency) is more common than many men realise. Estimates suggest around 1 in 4 men aged over 70 have testosterone levels below the normal range, with lower but still significant rates in younger age groups.

Younger men aren't immune. Secondary hypogonadism - where the problem lies in the brain's signalling to the testes rather than the testes themselves - can affect men in their twenties and thirties. Causes include obesity, chronic illness, anabolic steroid use (which suppresses natural testosterone production), and pituitary problems.

If you're a younger man experiencing these symptoms, it's still worth getting tested rather than assuming it can't apply to you.

Risks of leaving low testosterone untreated#

This isn't just about quality of life, though that matters considerably. Sustained testosterone deficiency carries some longer-term health implications:

• Bone density loss: testosterone is essential for maintaining bone strength. Prolonged deficiency increases the risk of osteoporosis and fracture
• Cardiovascular risk: the relationship between testosterone and heart health is complex, but low levels have been associated with increased cardiovascular risk in some studies
• Metabolic health: low testosterone is associated with insulin resistance and the metabolic syndrome, and may worsen type 2 diabetes management
• Mental health: persistent low mood and cognitive difficulties can have real effects on relationships, work, and wellbeing

None of this is intended to alarm - many men with mildly low testosterone live with minimal symptoms - but it does suggest that dismissing these symptoms indefinitely isn't a neutral choice.

Treatment options for low testosterone#

If blood tests confirm testosterone deficiency and symptoms are affecting your quality of life, several treatment approaches are available.

Testosterone replacement therapy (TRT)#

TRT corrects the hormone deficiency directly and is the primary medical treatment for confirmed hypogonadism. It's available through the NHS (usually via referral to an endocrinologist) or through private clinics. Formats include gels, injections, and patches, each with different practical considerations.

TRT isn't suitable for everyone. Men who wish to preserve fertility should be aware that exogenous testosterone suppresses sperm production - a conversation worth having with a specialist before starting. Regular monitoring of haematocrit, PSA, and lipid levels is required during treatment.

Lifestyle interventions#

For men with borderline levels, lifestyle factors can make a genuine difference. Sleep quality is particularly important - even a week of poor sleep measurably reduces testosterone. Resistance training, maintaining a healthy weight, reducing alcohol, and adequate zinc and vitamin D intake all support healthy hormone levels. These changes won't reverse clinical deficiency on their own, but they matter both as first-line support and as a complement to TRT.

Treating underlying causes#

Where low testosterone stems from obesity, type 2 diabetes, or sleep apnoea, addressing the root cause can partially restore levels. Weight loss in particular can produce meaningful improvements in testosterone for men who are significantly overweight. Totiva's weight loss service offers access to GLP-1 medications including Mounjaro and Wegovy for eligible patients, which can support significant weight reduction.

Getting tested#

If these symptoms sound familiar, the right first step is a blood test - not self-diagnosis, not supplements, and not testosterone gel ordered without a prescription. Testosterone therapy without appropriate clinical oversight carries real risks, including suppressing your own hormone production and raising red blood cell counts to dangerous levels.

Your GP can arrange a testosterone test on the NHS, or you can access private blood testing through services like Medichecks or Monitor My Health if you'd prefer quicker results. Either way, take the test in the morning and fast beforehand for the most reliable reading.

If you're looking to explore your options with a UK-registered clinician, Totiva's pharmacist-led online consultations offer a straightforward way to discuss symptoms and get appropriate guidance. You can start a consultation for free - you only pay if treatment is recommended and approved for you.