Low Libido in Men: Could It Be a Hormone Problem?
Low sex drive — also called hypoactive sexual desire disorder (HSDD) or low libido — is one of the most common and yet most frequently dismissed symptoms that men bring to their GP. The standard response is often a brief conversation about stress and lifestyle, with no hormonal investigation. For many men, this means a treatable medical cause is missed entirely.
While psychological factors certainly influence libido, a persistent and unexplained decline in sexual interest in men frequently has an identifiable hormonal or medical cause — and one that responds well to treatment when correctly identified.
Hormonal Causes of Low Libido in Men
Testosterone deficiency (hypogonadism) is the most important hormonal cause of low libido in men. Testosterone is the primary driver of sexual desire in men. Low testosterone levels — whether due to primary testicular failure or secondary causes (pituitary or hypothalamic dysfunction) — consistently produce a reduction in libido, often long before other symptoms of testosterone deficiency become apparent.
Hyperprolactinaemia — elevated prolactin levels (usually caused by a benign pituitary tumour called a prolactinoma) suppresses testosterone production and directly reduces libido. It is an important and treatable cause of low libido that is missed when prolactin is not included in the blood test panel.
Thyroid dysfunction — both hypothyroidism and hyperthyroidism can affect libido, through their effects on mood, energy, and hormonal regulation. Thyroid function should be part of any comprehensive assessment for low libido.
Oestrogen excess — men produce small amounts of oestrogen, which is converted from testosterone by the enzyme aromatase. In men with obesity or certain medical conditions, excessive aromatisation of testosterone to oestrogen suppresses testosterone levels and libido.
Non-Hormonal Causes
Not all low libido has a hormonal explanation. Other important contributors include:
- Depression and anxiety (the most common psychological causes)
- Relationship difficulties and intimacy problems
- Chronic pain or illness
- Medications (particularly SSRIs, opioids, beta-blockers, and some antihypertensives)
- Alcohol and substance misuse
- Sleep disorders and obstructive sleep apnoea
How We Assess Low Libido at London Andrology
A comprehensive assessment includes a detailed clinical history, physical examination, and a targeted blood test panel including:
- Total and free testosterone
- LH and FSH (to distinguish primary from secondary hypogonadism)
- Prolactin
- SHBG (sex hormone binding globulin)
- Thyroid function (TSH, free T4)
- Oestradiol where indicated
- Full blood count and metabolic panel
Blood tests for testosterone must be taken in the morning (ideally before 10am), as testosterone levels follow a diurnal rhythm with peak values in the early morning. Afternoon samples frequently return falsely low results.
Treatment Options
Where testosterone deficiency is confirmed on at least two morning samples, testosterone replacement therapy (TRT) — delivered as gels, injections, or implantable pellets — typically produces a significant improvement in libido within four to eight weeks.
Where hyperprolactinaemia is identified, dopamine agonist therapy (cabergoline) both lowers prolactin and restores testosterone to normal levels, with corresponding improvement in libido.
Psychological contributions are best addressed with specialist psychosexual therapy, which we can recommend alongside medical treatment where appropriate.
Book a Consultation
If you have noticed a sustained decline in your sexual interest that is not explained by stress or lifestyle factors, a hormonal assessment is a straightforward and often revealing first step. Contact London Andrology to see Professor Minhas or Professor Yap.
