Low Sexual Desire (Low Libido) in Men: What Causes It and How Is It Assessed?

Sexual desire, or libido, is often thought of in men as something expected to stay fixed at the same level. In reality, desire is the result of a complex interplay between hormones, physical health, mood, sleep, the relationship and life circumstances, and it naturally rises and falls over a lifetime. A period of reduced desire does not in itself mean illness; however, a reduction that persists, troubles the person or strains the relationship deserves assessment.

This article explains how low sexual desire differs from an erection problem, what can cause it, how it is assessed and why the treatment approach is shaped by the underlying cause.

What is sexual desire, and why does it fluctuate?

Sexual desire is the sum of sexual thoughts, fantasies and interest in sexual intimacy. The reward and motivation systems of the brain, hormones, testosterone above all, and the person's emotional state at the time together determine this interest. Desire has a side that arises spontaneously, and also a side that arises in response to a partner's closeness and a suitable setting.

It is ordinary for desire to decrease during periods such as a heavy workload, a newborn baby, bereavement, moving house or exams. The frequency and intensity of desire may also change somewhat with age. The yardstick in assessment is therefore not comparison with other people, but whether there has been a marked and persistent change relative to the person's own usual level, and whether that change causes distress to the person or in the relationship.

The difference between desire and function

Low sexual desire and erectile dysfunction are frequently confused, but they are different pictures:

• A desire problem: A reduction in sexual thoughts and interest. An erection may occur when the person is stimulated, but interest in and seeking out of sex has clearly diminished.
• A function problem: Desire is intact, but achieving or maintaining an erection sufficient for intercourse is difficult.

The two can also be present together in the same person. Testosterone deficiency can affect both desire and erections; on the other hand, desire may gradually decline in a man who has had difficulty with erections for a long time. Making this distinction matters because it determines where the assessment will place its emphasis. Performance anxiety and psychogenic erectile dysfunction are dealt with as a separate topic.

Hormonal causes

Hormones are among the first areas examined when low desire is assessed:

• Low testosterone: Low desire is one of the most typical symptoms of testosterone deficiency. It is often accompanied by tiredness, loss of energy, fewer morning erections and reduced muscle strength. Testosterone deficiency is covered in detail in a separate article on our site.
• Raised prolactin: A high level of prolactin, a hormone secreted by the pituitary gland, can markedly reduce desire and suppress testosterone production. Certain medicines or benign growths in the pituitary can cause this rise.
• Thyroid disorders: Both an underactive and an overactive thyroid can affect desire and sexual function.

Physical health, lifestyle and medicines

Desire is a sensitive indicator of general health. The following factors can reduce desire directly or indirectly:

• Chronic illness: Diabetes, obesity, kidney and liver disease, cardiovascular disease and chronic pain conditions.
• Sleep problems: Insufficient sleep and sleep apnoea affect both hormonal balance and energy.
• Stress, anxiety and depression: Reduced sexual interest is a common symptom of depression; prolonged stress can also suppress desire.
• Medicines: Some antidepressants, psychiatric medicines, hormonally active medicines, certain blood pressure and prostate medicines, and opioid painkillers can affect desire. It is important that these medicines are not stopped without consulting a doctor.
• Alcohol and substance use: Regular, heavy alcohol intake, cannabis and other substances can adversely affect hormonal balance and desire.

Relationship factors and the avoidance cycle

Sexual desire is not solely an individual matter; the state of the relationship strongly influences it. Unresolved conflict, communication difficulties, loss of trust, routine, or a mismatch in desire between partners can reduce sexual interest over time.

Another picture frequently encountered is the avoidance cycle. A man experiencing difficulty with erections or premature ejaculation begins to keep away from sexual intimacy out of fear of failing again. Over time this avoidance becomes a habit, and the person perceives it as a loss of desire. In this situation the real problem lies not in desire but in the underlying function problem and the anxiety that accompanies it; unless the point where the cycle began is addressed, the return of desire becomes difficult.

How is it assessed?

Assessment begins with a detailed history taken in confidence. The consultation covers the following headings:

• History: How long the low desire has lasted, whether it began suddenly or gradually, whether it occurs in all situations or only in certain ones, whether morning erections are present, and any accompanying erection or ejaculation problems.
• General health: Chronic illness, sleep patterns, weight change, mood, alcohol and substance use.
• Medication review: All medicines and supplements in use, and whether there is a time relationship between them and the fall in desire.
• Blood tests: Testosterone is measured in blood taken in the morning, after fasting; if it is found to be low, it is confirmed with a second morning measurement. Where needed, LH, FSH, prolactin, thyroid hormones, blood sugar and lipid values are also assessed.

Treatment approach

The treatment of low sexual desire is planned according to the cause identified. There is no single method applied to all patients:

• Hormonal causes: If raised prolactin or a thyroid disorder is found, these are treated first.
• Testosterone therapy: This is considered only in men whose deficiency has been confirmed by repeated morning measurements together with symptoms. Because testosterone given from outside can suppress sperm production, this is taken into particular account in men who wish to have children in the near future, and other options are considered. In men with normal hormone levels, testosterone therapy is not recommended as a way of increasing desire.
• Medication adjustment: Where a medicine affecting desire is involved, a change of dose or medicine may be considered together with the prescribing doctor.
• Lifestyle: Sleep patterns, weight management, regular physical activity, cutting down on alcohol and stress management can make a positive contribution to desire.
• An underlying function problem: If the source of the avoidance cycle is an erection or ejaculation problem, that problem is addressed first.
• Sex therapy and couples therapy: Where anxiety, depression and relationship factors are prominent, psychological support, sex therapy and couples therapy are an important part of treatment.

When should a doctor be consulted?

A urology and andrology assessment is advised in the following situations:

• Sexual desire having been markedly reduced for several months, troubling the person or the relationship
• Low desire accompanied by tiredness, loss of energy, fewer morning erections or breast tissue enlargement
• A fall in desire after starting a new medicine
• Erection or ejaculation problems occurring alongside low desire
• Men who wish to have children and are experiencing low desire

Low sexual desire in men is rarely tied to a single cause; hormones, general health, medicines, mood and the relationship all play a part together. Distinguishing desire from function, clarifying hormonal causes with morning blood tests and planning treatment according to the cause form the foundation of the process. Assoc. Prof. Zülfü Sertkaya practises in urology and andrology in Istanbul; assessment and treatment planning in low sexual desire are carried out with individual assessment and confidentiality.

Frequently Asked Questions