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# Male hypogonadism

The [testes](https://durgical.com/en/anatomy/testis/) make too little testosterone or sperm, from a testicular problem or a pituitary signal problem. It lowers libido, energy and bone strength.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Testes](https://durgical.com/en/anatomy/testis/)
- [Pituitary gland](https://durgical.com/en/anatomy/pituitary-gland/)
- [Scrotum](https://durgical.com/en/anatomy/scrotum/)
- [Epididymis](https://durgical.com/en/anatomy/epididymis/)
- [Prostate](https://durgical.com/en/anatomy/prostate/)
- [Hypothalamus](https://durgical.com/en/anatomy/hypothalamus/)

## In embryology

- [Gametogenesis: spermatogenesis and oogenesis](https://durgical.com/en/embryology/gametogenesis-spermatogenesis-and-oogenesis/)

## Why it happens

- [Sex chromosome disorders: Klinefelter and Turner](https://durgical.com/en/general-pathology/sex-chromosome-disorders-klinefelter-and-turner/)
- [Genomic imprinting: Prader–Willi and Angelman](https://durgical.com/en/general-pathology/genomic-imprinting-prader-willi-and-angelman/)
- [The male gonadal axis and spermatogenesis](https://durgical.com/en/physiology/the-male-gonadal-axis-and-spermatogenesis/)
- [Testosterone and its actions](https://durgical.com/en/physiology/testosterone-and-its-actions/)
- [Testis: seminiferous tubules, Sertoli and Leydig cells, spermatogenesis](https://durgical.com/en/histology/testis-seminiferous-tubules-sertoli-and-leydig-cells-spermatogenesis/)

## What it is

A clinical syndrome of testosterone deficiency, impaired sperm production, or both. Primary (hypergonadotropic) hypogonadism is due to testicular failure with high LH and FSH; secondary (hypogonadotropic) hypogonadism is due to hypothalamic or pituitary disease with low or inappropriately normal LH and FSH.

## Who gets it

Common in older men and strongly associated with obesity and type 2 diabetes, which are increasing in Colombia and Latin America. Klinefelter syndrome is the most common genetic cause of primary hypogonadism and is often diagnosed late, during evaluation for infertility.

## Causes

- Primary: Klinefelter syndrome (47,XXY), cryptorchidism, mumps orchitis, testicular trauma or torsion, chemotherapy or radiotherapy
- Secondary: Kallmann syndrome (with loss of smell), pituitary tumours, hyperprolactinaemia, hypopituitarism, haemochromatosis
- Functional: obesity, chronic illness, opioids, glucocorticoids, anabolic steroid use and excessive exercise or undernutrition
- Age-related decline in testosterone (late-onset hypogonadism)

## Risk factors

- Obesity, metabolic syndrome and type 2 diabetes
- Older age
- Chronic opioid, glucocorticoid or anabolic steroid use
- History of undescended testis, orchitis, testicular cancer treatment or pituitary disease

## Pathophysiology

GnRH from the [hypothalamus](https://durgical.com/en/anatomy/hypothalamus/) drives pituitary LH, which stimulates Leydig cells to make testosterone, and FSH, which with intratesticular testosterone supports spermatogenesis in Sertoli cells. Damage at any level reduces testosterone; the site is identified by whether LH and FSH rise (testicular failure) or not (central cause).

## Classification

- Primary (testicular): high LH and FSH
- Secondary (hypothalamic or pituitary): low or normal LH and FSH
- By onset: before puberty (eunuchoid proportions, absent puberty) or after puberty

## Symptoms and signs

- Low libido and erectile dysfunction
- Fatigue, low mood and reduced muscle mass and strength
- Infertility and small or soft testes
- Reduced body and facial hair; gynaecomastia
- Before puberty: delayed or absent puberty, high-pitched voice, long arms and legs
- Osteoporosis and low-trauma fractures

## Red flags

- Headache or visual field loss (pituitary mass)
- Testicular mass
- Very low testosterone with signs of other pituitary hormone deficiencies
- Absent puberty after age 14

## Diagnosis

**Clinical**
Symptoms plus examination of testicular volume and consistency, body hair, gynaecomastia, body proportions and sense of smell.

**Tests**
Two early-morning fasting total testosterone measurements; then LH and FSH to separate primary from secondary. Prolactin, iron studies and other pituitary hormones in secondary forms; karyotype when Klinefelter is suspected; semen analysis for fertility.

**Imaging**
Pituitary MRI when the cause is central and testosterone is very low or prolactin is raised; scrotal ultrasound for a mass; bone densitometry.

## Differential diagnosis

- Transient low testosterone from acute illness or sleep deprivation
- Depression and hypothyroidism (fatigue, low libido)
- Erectile dysfunction of vascular or neurogenic origin
- Androgen insensitivity syndrome
- Low sex hormone-binding globulin with normal free testosterone (obesity)

## Goal of treatment

Correct the underlying cause, restore testosterone to the normal range to relieve symptoms and protect bone, and preserve or restore fertility when it is desired.

## Treatment

**Lifestyle**
Weight loss, exercise and stopping opioids or anabolic steroids where possible, which can restore function in functional forms.

**Medical**
Testosterone replacement (injections, gels or patches) for confirmed deficiency in men not seeking fertility; it suppresses sperm production.

**Medical**
For fertility in secondary hypogonadism: gonadotropins (hCG with FSH) or GnRH; dopamine agonists when hyperprolactinaemia is the cause.

**Follow-up**
Testosterone levels, haematocrit (risk of polycythaemia), [prostate](https://durgical.com/en/anatomy/prostate/) assessment according to age, and bone density.

## Complications

- Osteoporosis and fractures
- Infertility
- Anaemia, loss of muscle mass and increased fat mass
- From treatment: polycythaemia, suppressed spermatogenesis and testicular atrophy

## Prognosis

Testosterone replacement improves sexual function, energy and bone density. Fertility can often be achieved in secondary hypogonadism with gonadotropins, but is limited in primary testicular failure.

## Test yourself

Think of the answer, then tap the question to see it.

## How do LH and FSH distinguish primary from secondary hypogonadism?

They are high in primary (testicular) failure and low or inappropriately normal in secondary (hypothalamic or pituitary) disease.

## What is the most common genetic cause of primary hypogonadism in men?

Klinefelter syndrome (47,XXY): small firm testes, gynaecomastia and infertility.

## Which syndrome combines hypogonadotropic hypogonadism with anosmia?

Kallmann syndrome, from failed migration of GnRH neurons.

## Why is testosterone therapy avoided in a man who wants to conceive?

Exogenous testosterone suppresses LH and FSH, reducing sperm production.

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## Related conditions

- [Klinefelter syndrome (47,XXY)](https://durgical.com/en/conditions/klinefelter-syndrome/)
- [Prolactinoma (hyperprolactinaemia)](https://durgical.com/en/conditions/prolactinoma/)
- [Hypopituitarism (incl. Sheehan syndrome and pituitary apoplexy)](https://durgical.com/en/conditions/hypopituitarism/)
- [Cryptorchidism (undescended testis)](https://durgical.com/en/conditions/cryptorchidism/)
- [Varicocele](https://durgical.com/en/conditions/varicocele/)
- [Erectile dysfunction](https://durgical.com/en/conditions/erectile-dysfunction/)
- [Gynaecomastia](https://durgical.com/en/conditions/gynaecomastia/)
- [Osteoporosis](https://durgical.com/en/conditions/osteoporosis/)
- [Obesity](https://durgical.com/en/conditions/obesity/)
- [Hereditary hemochromatosis](https://durgical.com/en/conditions/hereditary-hemochromatosis/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Hypogonadism](https://medlineplus.gov/ency/article/001195.htm) (MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine), 2025).

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Source: https://durgical.com/en/conditions/male-hypogonadism/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/male-hypogonadism/