Low Libido in Men: Causes, Diagnosis, and Treatment

Sexual desire — libido — is not a simple on-off switch. It is a complex interplay of hormones, mental health, relationship dynamics, and physical wellbeing. When this desire fades or disappears entirely, clinicians refer to it as low libido or Hypoactive Sexual Desire Disorder (HSDD). The issue is far more prevalent than most men assume: studies indicate that up to 15 per cent of men aged 18 to 59 report persistently reduced sexual desire — among men over 60, this figure rises above 25 per cent.

Yet the subject is rarely discussed openly. Many men feel shame, dismiss low libido as a natural part of ageing, or confuse it with erectile dysfunction. However, libido and erectile function are two distinct phenomena with different causes and treatment approaches. This article explains what lies behind the loss of sexual desire, when testosterone deficiency is the cause, and what treatment options are available — evidence-based and grounded in current research.

Libido vs. Erection: A Critical Distinction

Before analysing the causes of low libido, a fundamental distinction is necessary. Libido describes sexual desire — the wish for sexual activity. Erectile function describes the physical ability to achieve and maintain an erection. A man can have intact libido yet suffer from erectile problems (e.g. due to vascular causes). Conversely, a man can be physiologically capable of erection but feel no desire whatsoever.

This distinction is clinically relevant because it determines the diagnostic and therapeutic direction. A comprehensive review by Corona and Maggi (2022) emphasises that testosterone plays a central role in driving sexual desire, while erectile function depends more heavily on vascular and neurological factors (Corona & Maggi, 2022). This finding was confirmed by the large TRAVERSE trial: testosterone replacement therapy significantly improved sexual activity and desire in men with hypogonadism but had no effect on erectile function compared to placebo (Pencina et al., 2023).

The Most Common Causes of Low Libido in Men

Loss of sexual desire rarely has a single cause. In practice, multiple factors frequently overlap — hormonal, psychological, medication-related, and lifestyle-driven. A systematic evaluation is therefore essential before initiating treatment.

1. Testosterone Deficiency (Hypogonadism)

Testosterone is the primary hormone driving male libido. A decline in testosterone levels — whether age-related, disease-caused, or medication-induced — leads to a noticeable reduction in sexual desire for many men. The extensive review by Rastrelli, Corona, and Maggi (2018) demonstrates a clear threshold for libido: below a total testosterone level of approximately 8 nmol/L (roughly 230 ng/dL), sexual desire decreases significantly (Rastrelli et al., 2018).

The symptoms of testosterone-related libido loss typically develop gradually and are therefore often overlooked: interest in sex diminishes over months or years, sexual fantasies become less frequent, the frequency of sexual activity declines, and spontaneous sexual desire (including morning erections) fades. An isolated loss of libido is not sufficient for diagnosing hypogonadism — at least two early-morning blood draws confirming low testosterone are required. Detailed information about the relevant laboratory values can be found in our article on blood work for TRT.

2. Psychological Causes

Depression, anxiety disorders, and chronic stress are the most common psychological causes of low libido. The relationships are bidirectional: depression lowers testosterone levels, and low testosterone can amplify depressive symptoms — a vicious cycle that is often difficult to break. Chronic stress elevates cortisol levels, which directly inhibits testosterone production. Relationship difficulties, performance pressure, and negative body image can also substantially impair sexual desire.

Learn more about the interplay between testosterone and mental health in our article on testosterone and depression.

3. Medications

Numerous commonly prescribed medications can impair libido. The most important groups include selective serotonin reuptake inhibitors (SSRIs) and other antidepressants — these are among the most frequent medication-related causes of low libido, affecting up to 70 per cent of users. Equally problematic are beta-blockers and certain blood pressure medications, opioids and strong pain relievers that can massively suppress testosterone levels, 5-alpha reductase inhibitors (finasteride, dutasteride) for hair loss or benign prostatic hyperplasia, and anti-androgens and GnRH agonists.

If you suspect a connection between a medication and your libido loss, do not discontinue on your own — discuss this with your prescribing physician. Alternatives with less impact on sexual function are often available.

4. Lifestyle Factors

Overweight and obesity are strong predictors of low testosterone levels and reduced sexual desire. Adipose tissue contains the enzyme aromatase, which converts testosterone to oestradiol — the more adipose tissue, the greater the conversion and the lower the testosterone level. Additional relevant lifestyle factors include excessive alcohol consumption (chronic alcohol misuse damages Leydig cells and the hypothalamic-pituitary axis), sleep deprivation (just one week of 5-hour nights can reduce testosterone by 10–15 per cent), and physical inactivity and a sedentary lifestyle.

An overview of how to boost testosterone naturally is available in our dedicated guide.

5. Chronic Conditions

Type 2 diabetes, cardiovascular disease, chronic kidney disease, and liver conditions are all associated with low testosterone and impaired libido. Metabolic syndrome — the combination of overweight, hypertension, elevated blood lipids, and insulin resistance — is particularly closely linked to hypogonadism: up to 50 per cent of men with metabolic syndrome have demonstrably low testosterone levels.

Diagnosis: How Low Libido Is Investigated

A thorough diagnostic evaluation for low libido encompasses several levels that should be systematically addressed.

History and Questionnaires

The physician takes a detailed history covering the duration and progression of libido loss, accompanying symptoms (fatigue, mood changes, erectile difficulties), medication use, mental health and relationship situation, and lifestyle factors (sleep, alcohol, exercise, weight). Validated questionnaires such as the International Index of Erectile Function (IIEF) or the Aging Males' Symptoms (AMS) Score help systematically capture symptoms. An online self-test can provide initial indicators.

Laboratory Testing

Hormonal evaluation is the most important diagnostic step. The minimum panel includes total testosterone (morning, fasting, on at least two separate days), SHBG and free testosterone, LH and FSH to differentiate between primary and secondary hypogonadism, prolactin (elevated levels may indicate a pituitary adenoma), TSH (hypothyroidism is a common differential diagnosis), and HbA1c with fasting glucose. A comprehensive explanation of the relevant laboratory values is available in our dedicated article.

Differential Diagnosis

Not every case of low libido is hormonally driven, and not every low testosterone value causes symptoms. The physician must exclude alternative diagnoses before initiating therapy — particularly depression and anxiety disorders, thyroid conditions, hyperprolactinaemia, medication-induced sexual dysfunction, and relationship issues or psychosexual disorders.

Treatment: What Helps with Low Libido?

Treatment is directed at the underlying cause — a blanket approach is neither sensible nor medically justifiable.

Testosterone Replacement Therapy (TRT)

For confirmed hypogonadism, testosterone replacement therapy is the first-line treatment for libido-related symptoms. The Testosterone Trials (TTrials) demonstrated that 12 months of testosterone treatment in men over 65 with low testosterone significantly increased sexual activity (Cunningham et al., 2016). The larger TRAVERSE study confirmed and extended this finding: in 1,161 men with low testosterone and reduced libido, testosterone gel over 24 months improved sexual activity by an average of 0.49 additional acts per day compared to placebo and significantly increased sexual desire — and this effect was sustained throughout the entire 2-year period (Pencina et al., 2023).

Simultaneously, the TRAVERSE study showed that TRT did not improve erectile function — an important indication that libido and erection require different therapeutic approaches. For men experiencing both low libido and erectile dysfunction, a combination of TRT and PDE-5 inhibitors (e.g. sildenafil) may be appropriate, though this must be discussed individually with the treating physician.

Important: TRT is contraindicated in men with active fertility plans, as exogenous testosterone suppresses spermatogenesis. Detailed information on this topic is available in our article on TRT and fertility. Information about the costs of TRT in Switzerland can be found in our separate guide.

Lifestyle Modifications

For borderline testosterone levels or when no clear hormonal cause is present, lifestyle changes can be effective. Weight loss in overweight men can significantly raise testosterone levels — studies show increases of 2–5 nmol/L with weight reductions of 10–15 per cent. Regular resistance training stimulates short-term testosterone production and improves long-term body composition. Sleep hygiene is equally central: 7–9 hours of high-quality sleep is essential for optimal hormone production. Stress reduction through mindfulness practices, meditation, or cognitive behavioural therapy can lower cortisol levels and relieve suppression of testosterone production.

Psychotherapy and Couples Therapy

When psychological or relationship factors predominate, psychotherapeutic intervention is indicated. Cognitive behavioural therapy (CBT) has proven effective for sexual dysfunction, particularly when performance anxiety or negative cognitions block sexual desire. Couples therapy can be helpful when relationship difficulties contribute to or maintain libido loss. In many cases, a combined approach of medical treatment and psychotherapeutic support is most effective.

Medication Adjustment

When a medication is identified as the cause, the first step is discussing with the prescribing physician about switching to a preparation with less impact on sexual function. For SSRI-induced sexual dysfunction, switching to bupropion (which has less libido impact) or supplementing with other agents may be considered.

When to See a Doctor

A temporary dip in libido — during stressful life phases, for instance — is normal and not cause for concern. However, you should seek medical advice if the libido loss persists for longer than 2–3 months, if it affects your quality of life or your relationship, if it is accompanied by other symptoms (fatigue, weight gain, mood changes), or if you are over 40 and symptoms are worsening. Your first point of contact can be your GP, a urologist or endocrinologist, or a telemedicine consultation — all three pathways can lead to correct diagnosis and treatment.

FAQ

Is low libido normal in men?

A degree of fluctuation in sexual desire is entirely normal and influenced by many factors — stress, sleep quality, relationship dynamics, and overall health all play a role. What is not normal, however, is a persistent loss of sexual desire lasting months or years that impacts quality of life or the partnership. Studies show that up to 15 per cent of middle-aged men and over 25 per cent of men above 60 are affected by clinically relevant low libido. If your desire has noticeably and persistently declined, a medical evaluation is advisable — because behind the symptom may lie a treatable testosterone deficiency.

Does testosterone help with low libido?

Yes, for confirmed testosterone deficiency (hypogonadism), testosterone replacement therapy is the most effective treatment for low libido. The large TRAVERSE study involving over 1,100 men with low testosterone and reduced libido showed that testosterone gel over two years significantly improved sexual desire and sexual activity — and this effect was sustained throughout the entire treatment period. Importantly, testosterone improves sexual desire but has no direct effect on erectile function. If you suffer from both low libido and erectile problems, a combination of TRT and PDE-5 inhibitors (such as sildenafil) may be appropriate. A prerequisite for TRT is always a laboratory-confirmed testosterone deficiency — a self-assessment or a single blood value is not sufficient.

What are the most common causes of low libido in young men?

In men under 40, the most common causes are psychological: stress, performance pressure, depression, and anxiety disorders rank first. Medications also play a significant role — particularly antidepressants (SSRIs) and finasteride for hair loss can substantially impair libido. Hormonal causes are less common in young men but not excluded: to rule out testosterone deficiency, a blood test should always be performed when symptoms persist. Lifestyle factors such as sleep deprivation, heavy alcohol consumption, being overweight, and physical inactivity are frequently underestimated causes in younger men.

How do you distinguish low libido from erectile dysfunction?

Low libido and erectile dysfunction are two different problems that are frequently confused or conflated. Low libido means the desire for sex is absent — you think less about sex, have fewer sexual fantasies, and feel no wish for sexual activity. Erectile dysfunction means you feel desire but cannot physically achieve or maintain a sufficient erection. This distinction matters therapeutically: testosterone demonstrably improves libido but, according to the TRAVERSE study, has no direct effect on erectile function. Erectile problems are primarily treated with PDE-5 inhibitors (Viagra, Cialis), while libido loss due to testosterone deficiency is treated with TRT.

Further Reading

• Testosterone and Depression: Recognising the Connection
• TRT Costs in Switzerland
• How to Increase Testosterone Naturally