HYPOGONADISM

✓ Medically ReviewedDISEASEID: MDBT0282🚨 TRIAGE: ROUTINE

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Definition

CLINICAL DEFINITION

Hypogonadism is a clinical syndrome resulting from failure of the gonads (testes or ovaries) to produce physiological concentrations of sex steroids and/or gametes, due to pathology at one or more levels of the hypothalamic–pituitary–gonadal axis. It is classified as primary (hypergonadotropic) when the defect is gonadal, and secondary (hypogonadotropic) when the defect is hypothalamic or pituitary; a functional (normogonadotropic) form also exists, typically associated with metabolic or systemic illness, and may be reversible. Diagnosis in men requires both consistently low serum testosterone concentrations, measured under standardised morning fasting conditions, and relevant clinical symptoms.

IN PLAIN ENGLISH

Hypogonadism means the sex glands (testes in men, ovaries in women) do not make enough sex hormones, or do not produce sperm or eggs properly. This can cause problems with puberty, fertility, sexual function, energy, mood, and bone strength. It happens because of a problem either in the glands themselves or in the brain signals that control them.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Hypogonadism is NOT simply a low testosterone blood test result in isolation. A biochemical value below the reference range must be interpreted together with consistent clinical features and confirmed on a properly collected repeat sample; asymptomatic low values, transient declines during acute illness, and normal age-related variation are not sufficient to establish the diagnosis.

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Word Breakdown

hypo-

=under, below normal

gonad-

=gonad (from Greek 'gonē' — seed, offspring)

-ism

=condition, state (from Greek '-ismos')

Literal Meaning: A condition of under-function of the gonads

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Abbreviations

HH=Hypogonadotropic Hypogonadism — secondary hypogonadism due to hypothalamic-pituitary failure

LOH=Late-Onset Hypogonadism — age-related functional testosterone decline in men

POI=Primary Ovarian Insufficiency — the female equivalent of primary hypogonadism

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Synonyms & Variants

Gonadal Deficiency›Testosterone Deficiency (male context)›Ovarian Insufficiency (female context)›

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Category-Specific Context

Hypogonadism is a Disease because it is a defined clinical syndrome with recognised diagnostic criteria and a classification framework (primary, secondary, and functional). The primary/secondary distinction is made by measuring gonadotropins (luteinising hormone and follicle-stimulating hormone): elevated gonadotropins indicate gonadal failure (primary), while low or inappropriately normal gonadotropins indicate hypothalamic-pituitary dysfunction (secondary). Functional hypogonadism is a reversible form associated with systemic illness or metabolic disturbance, and is increasingly recognised as the most common presentation in ageing men.

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Clinical Context & Usage

CLINICAL SETTINGS

Endocrinology Outpatient ClinicUrology ClinicReproductive Medicine ClinicGeneral Medicine WardPaediatric Endocrinology ClinicPrimary Care

USAGE & DOCUMENTATION NOTES

In clinical documentation, the term is usually qualified as primary, secondary, or functional hypogonadism, and in men the phrase 'symptomatic testosterone deficiency' is often used interchangeably. Gonadotropin levels are reported alongside sex hormone concentrations to establish the level of axis failure. In fertility contexts, the term is frequently paired with semen analysis findings, and in older men the designation 'late-onset hypogonadism' is used when no organic cause is identified. When testosterone therapy is discussed, the documented diagnosis should specify the underlying cause and the confirmed biochemical threshold.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

The hypothalamic–pituitary–gonadal axis regulates gonadal function through pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus, which stimulates pituitary release of luteinising hormone (LH) and follicle-stimulating hormone (FSH). In men, LH drives Leydig cell testosterone production and FSH supports spermatogenesis; in women, LH and FSH regulate ovarian steroidogenesis and folliculogenesis. Primary hypogonadism results from gonadal damage or dysfunction, removing negative feedback and causing compensatory elevation of LH and FSH (hypergonadotropic state). Secondary hypogonadism results from hypothalamic or pituitary failure, producing low or inappropriately normal gonadotropins and consequent gonadal quiescence (hypogonadotropic state). Functional hypogonadism arises when the axis is suppressed by systemic illness, metabolic disturbance, obesity, or medications, without structural hypothalamic-pituitary disease, and may reverse when the underlying condition is treated. The clinical consequences reflect loss of sex steroid action (impaired sexual function, bone loss, altered body composition) and, where relevant, impaired gametogenesis.

PRIMARY CAUSES

Klinefelter syndrome (47,XXY and variants)

Supernumerary X chromosome material causes seminiferous tubule dysgenesis and progressive Leydig cell failure, producing primary hypergonadotropic hypogonadism; it is the most common congenital cause of primary hypogonadism in men.

Cryptorchidism (undescended testis)

Failure of testicular descent exposes the testis to higher core body temperature, impairing germ cell development and, when bilateral or prolonged, Leydig cell function; bilateral cryptorchidism is a recognised cause of primary hypogonadism.

Testicular trauma, torsion, or orchiectomy

Direct loss or ischaemic damage to testicular tissue reduces the functional Leydig and Sertoli cell mass, lowering testosterone and inhibin production and removing negative feedback, which raises gonadotropins.

Orchitis (e.g., mumps orchitis)

Inflammatory destruction of testicular parenchyma, particularly after pubertal mumps infection, can cause permanent testicular insufficiency with elevated gonadotropins.

Hypothalamic or pituitary lesions (tumours, trauma, radiation, infiltrative disease)

Damage to GnRH-secreting neurons or pituitary gonadotroph cells reduces LH and FSH output, leading to secondary hypogonadism with low or inappropriately normal gonadotropins.

Kallmann syndrome (congenital hypogonadotropic hypogonadism with anosmia)

Failure of GnRH neuron migration during embryogenesis results in isolated hypogonadotropic hypogonadism, often accompanied by anosmia or hyposmia.

Hyperprolactinaemia (e.g., prolactinoma, medication-induced)

Elevated prolactin suppresses GnRH pulsatility and gonadotropin secretion, producing secondary hypogonadism; in men, macroprolactinomas are a recognised cause.

Functional suppression of the axis (obesity, metabolic syndrome, chronic illness, excessive exercise, eating disorder)

Systemic metabolic or inflammatory stress suppresses hypothalamic GnRH drive, lowering gonadotropins and testosterone without intrinsic hypothalamic-pituitary or gonadal disease; this form may be reversible with treatment of the underlying condition.

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Drug-Induced Causes

💊 Opioids (e.g., morphine, oxycodone, fentanyl, methadone) ↗

Mechanism: Opioid receptor activation in the hypothalamus and pituitary suppresses pulsatile GnRH release and gonadotropin secretion, leading to secondary hypogonadism; severity is dose- and duration-related.

→ Review the indication and consider dose reduction or alternative analgesia where feasible; testosterone therapy may be considered if hypogonadism persists and the opioid cannot be discontinued, with monitoring.

💊 Glucocorticoids (systemic, chronic use) ↗

Mechanism: Exogenous corticosteroids suppress pituitary LH and FSH secretion and may also impair gonadal steroidogenesis, contributing to secondary hypogonadism, particularly with prolonged or high-dose therapy.

→ Use the lowest effective glucocorticoid dose and consider steroid-sparing strategies; assess the gonadal axis if symptoms develop during long-term therapy.

💊 Androgen deprivation therapy (GnRH agonists/antagonists, antiandrogens, androgen synthesis inhibitors) ↗

Mechanism: These agents intentionally suppress gonadal androgen production or action, producing profound hypogonadism as a therapeutic effect in prostate cancer.

→ The hypogonadal state is expected; manage consequences such as bone loss and metabolic effects according to oncology and supportive care guidance, with periodic monitoring.

💊 Anabolic–androgenic steroids (exogenous testosterone or synthetic androgens) ↗

Mechanism: Exogenous androgens suppress endogenous GnRH and gonadotropin secretion through negative feedback, causing secondary hypogonadism and impaired spermatogenesis during use and potentially after cessation.

→ Counsel on the risk of suppression; if fertility is desired, discontinuation under specialist guidance with monitoring of axis recovery is required.

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Epidemiology

Prevalence:In men aged 40–79 years, international studies report a prevalence of symptomatic hypogonadism of approximately 2.1–5.7%; the crude prevalence of symptomatic hypogonadism among middle-aged and older men has been estimated at around 5.6% in some cohorts. Prevalence increases with age and is substantially higher in men with obesity, type 2 diabetes, metabolic syndrome, chronic kidney disease, COPD, and cancer. Primary ovarian insufficiency, the female equivalent of primary hypogonadism, affects approximately 1–1.9% of women under 40 years in population-based estimates.

Age Group:Congenital forms (e.g., Klinefelter syndrome, Kallmann syndrome) present in infancy, childhood, or adolescence with delayed or absent puberty. Acquired primary and secondary forms can occur at any age. Late-onset hypogonadism in men is most commonly identified in mid-to-late adulthood, with prevalence rising after 40–50 years; primary ovarian insufficiency typically presents before age 40.

Sex Predilection:Equal

Geographic Distribution:Hypogonadism occurs worldwide. The distribution of specific causes varies: Klinefelter syndrome is present across populations with a relatively stable birth prevalence, while functional hypogonadism tracks with the global prevalence of obesity and metabolic syndrome. Iodine status and access to healthcare influence the recognition of hypothalamic-pituitary causes; no consistent geographic predilection for hypogonadism itself has been established.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 ROUTINE

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

A low testosterone result in a man with headache, visual field defect, or other pituitary mass symptoms raises concern for a pituitary or hypothalamic lesion; such patients require urgent pituitary imaging and assessment for additional hormone deficiencies, not simply testosterone replacement.
Hypogonadism presenting with a sellar mass and bitemporal hemianopia or acute headache should prompt urgent evaluation for pituitary apoplexy, which is a medical emergency requiring immediate neurosurgical and endocrine input.
In a man with hypogonadism and a history of testicular trauma, torsion, or bilateral cryptorchidism, the finding suggests primary testicular failure; do not attribute symptoms solely to ageing or functional causes without confirming the gonadotropin pattern.

URGENT EVALUATION TRIGGERS

Sudden severe headache with visual field loss or ophthalmoplegia in a patient with known or suspected hypogonadism — evaluate urgently for pituitary apoplexy.
Hypogonadism with signs of adrenal crisis (hypotension, hyponatraemia, hyperkalaemia) — urgent assessment for combined pituitary hormone deficiency is required.
New-onset hypogonadism with galactorrhoea and visual disturbance — urgent evaluation for a prolactinoma or other sellar mass.
Suspected testicular torsion presenting with acute scrotal pain — immediate surgical assessment, independent of the hypogonadism diagnosis.

Contraindications & Precautions

CONTRAINDICATIONS

Breast cancer or prostate cancer — testosterone therapy is contraindicated in men with known breast or prostate cancer; in prostate cancer
this reflects the androgen-sensitive nature of the disease and should be managed by the oncology team.
Planning fertility in the near term — testosterone therapy suppresses spermatogenesis and is not appropriate when immediate fertility is desired; gonadotropin therapy or other fertility-preserving approaches should be considered instead.
Palpable prostate nodule or induration
or prostate-specific antigen (PSA) > 4 ng/mL without urological evaluation — testosterone therapy should not be started until prostate pathology has been assessed.
Elevated haematocrit (e.g.
> 48–50%) — testosterone therapy can further increase haematocrit and thrombotic risk; the threshold and management should follow local protocol and specialist guidance.
Uncontrolled or untreated severe heart failure — testosterone therapy may cause fluid retention and is not recommended in uncontrolled heart failure.
Myocardial infarction or stroke within the last 6 months — initiating testosterone therapy in this window is not recommended due to cardiovascular risk considerations.

SPECIAL PRECAUTIONS

Confirm the diagnosis with at least two morning fasting total testosterone measurements before starting therapy; do not treat on the basis of a single value.
Assess and document the primary versus secondary level using gonadotropins (LH and FSH) before treatment
as this determines the need for further pituitary evaluation and informs management.
Monitor haematocrit at baseline and during therapy; dose adjustment or cessation may be required if haematocrit rises significantly.
Monitor prostate-specific antigen (PSA) and perform digital rectal examination as clinically indicated
particularly in men aged 55–69 years or those at increased prostate cancer risk.
Consider the risk of suppressed spermatogenesis and discuss fertility intentions before starting testosterone therapy; alternative treatments are available if fertility is a priority.
In functional hypogonadism
address the underlying metabolic or systemic condition before or alongside considering hormone therapy
as the axis may recover.

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Osteoporosis and increased fracture risk — sex steroid deficiency accelerates bone loss; in men
untreated long-standing hypogonadism is a recognised cause of male osteoporosis.
Metabolic syndrome and altered body composition — reduced testosterone is associated with increased visceral adiposity
reduced lean mass
and insulin resistance
with a bidirectional relationship.
Cardiovascular risk — severe and prolonged testosterone deficiency has been associated with adverse cardiovascular risk profiles
although causality and the effect of replacement remain areas of uncertainty.
Anaemia — androgen deficiency can contribute to normocytic or mildly macrocytic anaemia through reduced erythropoietic drive.
Impaired fertility — depending on the cause and gonadotropin status
spermatogenesis or folliculogenesis may be impaired
ranging from reduced fertility to azoospermia or anovulation.
Psychological and sexual dysfunction — reduced libido
erectile dysfunction
low mood
and reduced quality of life are common and clinically significant consequences.

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Reference Ranges

NORMAL RANGETotal testosterone reference ranges are assay- and laboratory-specific; in many laboratories the lower limit of the normal range in healthy young men is approximately 10.4 nmol/L (300 ng/dL). The Endocrine Society and EAU diagnostic thresholds for symptomatic male hypogonadism are typically around ≤ 12 nmol/L (≈ 3.5 ng/mL) on confirmatory testing, but the lower limit of the reporting laboratory should be used for interpretation.

CRITICAL (PANIC) VALUEA total testosterone concentration below approximately 8 nmol/L (≈ 2.3 ng/mL) is often used to define severe biochemical hypogonadism and warrants prompt specialist evaluation, particularly when associated with symptoms or additional pituitary hormone deficiencies. No universally accepted single 'critical value' mandates emergency action; the clinical context and trajectory determine urgency.

UNIT OF MEASUREMENTnmol/L (SI); ng/dL (conventional). Conversion: 1 nmol/L ≈ 28.8 ng/dL.

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Hypogonadism vs. Hypergonadism

Sound-alike terms with opposite meanings. Hypergonadism refers to excessive gonadal hormone production, not deficiency; confusion can lead to reversed interpretation of laboratory results and clinical findings.

Hypogonadism vs. Hypopituitarism

Related but distinct: hypopituitarism is failure of multiple pituitary hormones, of which hypogonadism may be one component. Documenting 'hypogonadism' when panhypopituitarism is present may under-represent the need for broader hormone replacement.

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Functional hypogonadism (metabolic/obesity-related)

Key Distinguishing Feature: Low or low-normal testosterone with normal or mildly elevated gonadotropins in the setting of obesity, metabolic syndrome, or chronic illness; may reverse with treatment of the underlying condition, and structural hypothalamic-pituitary disease is absent.

Primary hypogonadism (gonadal failure)

Key Distinguishing Feature: Low testosterone with elevated LH and FSH (hypergonadotropic pattern); indicates testicular or ovarian failure and is not reversed by treating systemic conditions.

Secondary hypogonadism (hypothalamic-pituitary failure)

Key Distinguishing Feature: Low testosterone with low or inappropriately normal LH and FSH; requires evaluation for pituitary or hypothalamic pathology, including other pituitary hormone deficiencies.

Androgen insensitivity or end-organ resistance

Key Distinguishing Feature: Normal or elevated testosterone with impaired virilisation or persistent symptoms despite adequate hormone concentrations; the defect is at the androgen receptor or post-receptor level, not hormone production.

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Clinical Pearls

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Always measure total testosterone in the morning (ideally 7:00–10:00 AM) and in the fasting state; values obtained later in the day or after glucose intake are systematically lower and can lead to overdiagnosis of hypogonadism.

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The gonadotropin pattern is the key branch point: elevated LH and FSH indicate primary gonadal failure, whereas low or inappropriately normal gonadotropins indicate secondary hypothalamic-pituitary failure and warrant pituitary evaluation, including prolactin and other pituitary hormones.

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Functional hypogonadism is common in obesity, metabolic syndrome, and chronic illness and may reverse with treatment of the underlying condition; testosterone therapy should not be started without first considering and addressing reversible contributors.

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Testosterone therapy suppresses spermatogenesis and is not a treatment for infertility; in men desiring fertility, gonadotropin therapy (hCG with or without FSH) is the appropriate approach under specialist guidance.

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In men aged 55–69 years being considered for testosterone therapy, shared decision-making about prostate cancer risk assessment and monitoring is recommended; PSA and haematocrit should be checked at baseline and during therapy.

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Example Usage & SOAP

CLINICAL SENTENCE

"A 58-year-old man with type 2 diabetes and a body mass index of 34 kg/m² reported reduced libido and morning erections; two fasting 8 AM total testosterone measurements were 7.8 nmol/L and 8.1 nmol/L, with LH 4.2 IU/L and FSH 5.1 IU/L, consistent with functional hypogonadism, and lifestyle intervention was prioritised before considering testosterone therapy."

IN A SOAP NOTE

S: 58-year-old man reports 12 months of reduced libido, fatigue, and poor morning erections. O: BMI 34 kg/m², waist circumference 112 cm; two fasting 8 AM total testosterone 7.8 and 8.1 nmol/L; LH 4.2 IU/L, FSH 5.1 IU/L, prolactin normal; haematocrit 44%; PSA 1.2 ng/mL. A: Symptomatic hypogonadism with a functional, normogonadotropic pattern in the context of obesity and type 2 diabetes; no biochemical evidence of primary testicular failure or pituitary disease. P: Structured weight-loss and exercise programme; repeat testosterone in 3–6 months; if symptoms persist and biochemical confirmation remains, discuss trial of testosterone therapy with monitoring of haematocrit and PSA.

DIFFERENTIAL DIAGNOSIS CONTEXT

Differential for hypogonadism: (1) Primary hypogonadism — elevated LH/FSH, gonadal cause (e.g., Klinefelter syndrome, orchitis, trauma); (2) Secondary hypogonadism — low/inappropriately normal LH/FSH, hypothalamic-pituitary cause (e.g., prolactinoma, Kallmann syndrome, pituitary radiation); (3) Functional hypogonadism — low/normal gonadotropins in obesity, metabolic syndrome, or chronic illness, potentially reversible; (4) Androgen resistance — normal or elevated testosterone with persistent symptoms, suggesting end-organ insensitivity. The gonadotropin pattern and clinical context distinguish these categories.

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Classifications & Scoring

SCORING TOOL

Aging Males' Symptoms (AMS) Scale

A 17-item questionnaire assessing psychological, physical, and sexual symptoms associated with late-onset hypogonadism; scores are used for symptom profiling and monitoring, but the scale has limited specificity for biochemical testosterone deficiency and should not replace hormone measurement.

SCORING TOOL

Androgen Deficiency in Aging Males (ADAM) Questionnaire

A screening questionnaire for androgen deficiency in ageing men; a positive screen (e.g., low libido or low morning erections plus other symptoms) prompts biochemical testing, but the diagnosis still requires confirmed low testosterone.

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Prognosis

SHORT-TERM OUTCOME

Short-term prognosis depends on the cause and reversibility. Functional hypogonadism may improve when the underlying illness or metabolic disturbance is treated. In organic primary or secondary hypogonadism, hormone concentrations do not recover spontaneously in most cases, but symptoms often respond to appropriate hormone replacement, with improvement in sexual function, mood, and bone turnover markers over weeks to months.

LONG-TERM PROGNOSIS

Long-term outcomes are determined by the underlying cause and whether replacement is undertaken. Congenital hypogonadism requires lifelong therapy to maintain secondary sexual characteristics and bone health. Untreated long-standing hypogonadism is associated with progressive bone loss, adverse metabolic changes, and impaired fertility. Observational data link severe testosterone deficiency in men to increased mortality risk, but this association is confounded by comorbidity, and causality is not established; the effect of testosterone therapy on long-term mortality remains uncertain.

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References & Coding

LITERATURE CITATIONS & GUIDELINES

[1]Bhasin S, Brito JP, Cunningham GR, Hayes FJ, Hodis HN, Matsumoto AM, Snyder PJ, Swerdloff RS, Wu FC, Yialamas MA. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. doi:10.1210/jc.2018-00229.

[2]Salonia A et al. EAU Guidelines on Sexual and Reproductive Health: A Summary of the 2026 Recommendations for Measurement and Biochemical Confirmation of Hypogonadism. Eur Urol. 2026. doi:10.1016/j.eururo.2026.01.001.

[3]Grossmann M, Matsumoto AM. Epidemiology of Male Hypogonadism. Endocrinol Metab Clin North Am. 2022;51(1):1-27. doi:10.1016/j.ecl.2021.11.001.

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