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Health condition · Clinically reviewed

Hypogonadism, testosterone, HRT and specialist fertility care.

Low sex hormones in men or women - a treatable condition that deserves a clear diagnosis and a considered specialist plan.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against the Endocrine Society, BSSM, BMS and NICE - sources listed at the end.

  • 03

    Current for 2026

    Reflects modern UK practice for testosterone replacement, HRT and specialist fertility care.

Key facts

Hypogonadism at a glance.

The essentials, in plain English - what it is, the different types, and how it\'s treated in the UK today.

  • What it is

    Reduced sex-hormone production - low testosterone in men, low oestradiol in women - with symptoms that follow.

  • Primary hypogonadism

    The gonad itself fails - LH and FSH are raised. Klinefelter, Turner, POI, chemo or radiotherapy, autoimmune disease.

  • Secondary hypogonadism

    The pituitary or hypothalamus signal fails - LH and FSH are low or inappropriately normal. Includes Kallmann and pituitary tumours.

  • Late-onset (male)

    Age-related decline in testosterone - sometimes called andropause. Diagnosis needs symptoms and confirmed low morning testosterone.

  • Presentation

    Men - low libido, erectile dysfunction, fatigue, gynaecomastia. Women - amenorrhoea, hot flushes, infertility, vaginal atrophy.

  • Treatment

    Testosterone replacement in men, HRT in women, fertility-specific therapy where a pregnancy is wanted, plus treating the underlying cause.

Why this guide matters

A specialist condition, explained clearly.

Hypogonadism is often missed or over-treated. The three points below shape the rest of this page.

  • Diagnosis needs symptoms and bloods

    A one-off testosterone number is not enough - morning fasting samples, LH, FSH and repeat testing are the foundation of any credible diagnosis.

  • Fix the cause, not just the number

    Pituitary tumours, hyperprolactinaemia, haemochromatosis, low weight and opioid use can all be reversed - screen before starting long-term hormones.

  • Long-term treatment needs monitoring

    Testosterone and HRT are safe and effective when properly monitored - haematocrit, PSA, lipids and bone density all matter.

How the diagnosis is made

From symptoms to a confirmed plan.

The steps a UK endocrinologist, andrologist or gynaecologist will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    History and symptom review

    Onset, sexual function, fertility plans, mood, energy - and any relevant family history including Klinefelter or Kallmann.

  2. 02

    Assessing

    Focused examination

    Tanner staging in adolescents, testicular volume, gynaecomastia, body composition, BMI and features of pituitary disease.

  3. 03

    Assessing

    Morning bloods

    Fasting 9am testosterone (men), oestradiol (women), LH, FSH, SHBG and calculated free testosterone - repeated to confirm.

  4. 04

    Confirming

    Wider hormone screen

    Prolactin, thyroid function, ferritin and transferrin saturation, AMH in women - looking for reversible or systemic causes.

  5. 05

    Confirming

    Imaging and genetics

    MRI pituitary if secondary hypogonadism, karyotype where Klinefelter or Turner are suspected - specialist commissioned.

  6. 06

    Planning

    Fertility and bone workup

    Semen analysis in men, ovarian reserve tests in women, and a DEXA scan to check bone mineral density.

  7. 07

    Planning

    Specialist MDT review

    Endocrinology, andrology, gynaecology and fertility teams shape the treatment plan - specialist commissioned where relevant.

Typical pathway: first bloods to a confirmed diagnosis and specialist plan in a matter of weeks.

Symptoms

What hypogonadism looks like.

A mix of sexual, physical and metabolic changes - in both sexes - plus the delayed puberty picture in adolescents.

  • Low libido and sexual function

    Reduced desire and, in men, erectile dysfunction - a common early feature that often prompts testing.

  • Fatigue and low mood

    Persistent tiredness, low motivation and mood changes that don't fit obvious lifestyle causes.

  • Body composition changes

    Reduced muscle mass and strength, increased body fat - particularly central - despite a stable routine.

  • Gynaecomastia (men)

    Development of breast tissue in men - especially when testosterone is low and oestrogen relatively preserved.

  • Menstrual disturbance (women)

    Amenorrhoea or oligomenorrhoea, hot flushes and vaginal atrophy - the pattern of oestrogen deficiency.

  • Infertility

    Difficulty conceiving in both sexes - often the reason a young adult is referred and hypogonadism is uncovered.

  • Delayed puberty

    Absent or delayed pubertal changes in adolescents - a paediatric endocrinology referral is essential.

  • Bone health

    Osteoporosis and fragility fractures - the long-term consequence of untreated sex-hormone deficiency in either sex.

Treatment

How hypogonadism is treated in the UK.

Treat the underlying cause where possible, replace what is missing, and preserve fertility, mood and bone health.

  • Treat the underlying cause

    Pituitary tumour management, treating hyperprolactinaemia, venesection for haemochromatosis, weight and lifestyle change where relevant.

  • Testosterone gels

    Daily transdermal preparations (AndroGel, Testogel, Testavan) - steady levels and easy to titrate. First-line for many men.

  • Testosterone injections

    Nebido (testosterone undecanoate) as a long-acting intramuscular injection every 10 to 14 weeks - specialist andrology.

  • Fertility-focused therapy

    Gonadotrophins (hCG and FSH) or clomifene stimulate the testes or ovaries where secondary hypogonadism is present and a pregnancy is wanted.

  • HRT for women

    Oestrogen with a progestogen if the uterus is present - restoring hormone levels, protecting bone and easing symptoms. Specialist commissioned where indicated.

  • Kallmann syndrome

    Specialist commissioned - pulsatile GnRH or gonadotrophin therapy where fertility is wanted, testosterone or oestrogen replacement otherwise.

  • Paediatric induction of puberty

    Delayed puberty is a specialist paediatric endocrinology issue - low-dose testosterone or oestrogen used to induce puberty carefully.

  • Long-term monitoring

    Testosterone level, haematocrit, PSA and prostate exam, lipids and bone mineral density (DEXA) at agreed intervals.

What this guide is based on

The sources behind every claim on this page.

National and international guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, endocrinologist or gynaecologist knows your history and can say which parts apply to you. If in doubt, get seen.

  • Endocrine Society. Clinical practice guideline on testosterone therapy in men with hypogonadism.

  • British Society for Sexual Medicine (BSSM). Guidelines on adult testosterone deficiency.

  • British Menopause Society (BMS). Guidance on premature ovarian insufficiency and HRT.

  • NICE. Menopause: diagnosis and management (NG23) and hypopituitarism guidance.

  • Royal College of Obstetricians and Gynaecologists (RCOG). Turner syndrome and POI guidance.

Red flags

When hypogonadism needs urgent attention.

Most cases are managed calmly in outpatients. These are the situations that aren\'t - and where a specialist opinion is needed quickly.

  • Visual field loss or headache

    Suggests a pituitary or hypothalamic mass - a same-week MRI and specialist review are needed.

  • Pituitary apoplexy

    Sudden severe headache with visual change or collapse - an emergency requiring hospital assessment.

  • Testicular torsion

    Acute severe testicular pain and swelling - urgent urology referral within hours.

  • Suspected Klinefelter

    Small firm testes, tall stature, gynaecomastia - karyotype and specialist andrology input.

  • Suspected Turner

    Short stature, primary amenorrhoea, cardiac or renal anomalies - specialist paediatric or adult endocrinology.

  • Kallmann features

    Delayed puberty with anosmia - specialist commissioned care via a supraregional endocrine service.

  • Osteoporotic fracture

    A fragility fracture in a young or middle-aged patient - hypogonadism must be excluded and DEXA arranged.

  • Haemochromatosis features

    Fatigue, arthralgia, raised transferrin saturation - iron overload can cause pituitary and gonadal failure.

  • Fertility concerns

    Where a pregnancy is wanted, refer early - some treatments (like exogenous testosterone) suppress fertility.

Living with it

Treatable, with the right monitoring.

Four things that make the biggest difference day to day - consistent treatment, attending your checks, protecting your bones and planning fertility early.

A quiet reminder

Well-monitored replacement is safe replacement.

Testosterone and HRT are safe long-term when the checks are done - haematocrit, PSA, lipids and bone density all matter.

  1. 01 Routine

    Take treatment consistently

    Gels, injections and HRT work best when taken on schedule - set reminders and keep a simple log of side effects.

  2. 02 Monitoring

    Attend your checks

    Testosterone level, haematocrit, PSA, lipids and BMD reviews aren't optional - they keep therapy safe long-term.

  3. 03 Bone

    Protect your skeleton

    Weight-bearing exercise, adequate calcium and vitamin D, and stopping smoking all help - DEXA at agreed intervals.

  4. 04 Fertility

    Plan pregnancies early

    If you may want children, tell your specialist before starting testosterone - fertility-preserving options exist.

Frequently asked

Everything we get asked about hypogonadism.

Quick answers on diagnosis, testosterone replacement, HRT, Kallmann syndrome and long-term safety.

  • What is hypogonadism?

    Hypogonadism is reduced production of sex hormones - testosterone in men, oestradiol in women. It can be primary (the gonad fails, with raised LH and FSH), secondary (the pituitary or hypothalamus fails, with low LH and FSH) or late-onset in men. Symptoms include low libido, erectile dysfunction, fatigue, menstrual disturbance, infertility and bone loss.

  • How is it diagnosed?

    A careful history and examination, then blood tests taken in the morning - testosterone (fasting) or oestradiol, together with LH, FSH, SHBG, prolactin, thyroid function and iron studies. Imaging of the pituitary, karyotype testing, semen analysis and a DEXA scan are added when the picture points that way. Diagnosis is confirmed with repeat testing under specialist review.

  • What are the options for men?

    Testosterone replacement is the mainstay - usually transdermal gels (AndroGel, Testogel, Testavan) or long-acting intramuscular injections (Nebido) every 10 to 14 weeks. Where fertility is wanted, gonadotrophin therapy or clomifene may be used instead. All treatment is guided by BSSM and Endocrine Society standards, with long-term monitoring of PSA, haematocrit, lipids and bone density.

  • What are the options for women?

    Hormone replacement therapy (oestrogen with a progestogen if the uterus is still present) restores hormone levels, controls hot flushes, protects the bones and helps vaginal atrophy. For women who want to conceive, fertility care is added. Premature ovarian insufficiency (POI) is a common indication - specialist menopause and fertility input is important.

  • What is Kallmann syndrome?

    Kallmann syndrome is a genetic form of secondary hypogonadism where GnRH neurons fail to migrate properly during development - so puberty doesn't start naturally and there is often anosmia (loss of smell). It is managed as specialist commissioned care - pulsatile GnRH or gonadotrophin therapy for fertility, testosterone or oestrogen replacement otherwise.

  • Is testosterone therapy safe long-term?

    When it is prescribed for genuine hypogonadism and monitored properly, yes. Regular reviews check symptoms, testosterone levels, haematocrit (to avoid polycythaemia), PSA and the prostate, lipids and bone mineral density. It should not be prescribed casually for age-related fatigue without a confirmed low morning testosterone and a considered specialist plan.

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