Hypogonadism

What is hypogonadism?

Hypogonadism is a condition in which the body’s sex glands, called the gonads, produce little or no sex hormones. In men, the gonads are the testicles, which make the hormone testosterone and produce sperm. In women, the gonads are the ovaries, which make estrogen and progesterone. When people ask “what is hypogonadism,” the simplest answer is this: it is an underactivity of the testicles or ovaries that leads to low levels of sex hormones and, in many cases, reduced fertility.

The medical code E29.1 refers specifically to testicular hypofunction, meaning underactive testicles in men and boys. For that reason, this article focuses mainly on male hypogonadism, although many of the general principles also apply to women with underactive ovaries.

Doctors divide hypogonadism into two main types, based on where the problem starts:

• Primary hypogonadism: the problem lies in the testicles themselves. The brain sends the correct hormonal signals, but the testicles cannot respond properly. This is sometimes called hypergonadotropic hypogonadism, because the signaling hormones from the brain are actually high as the body tries to stimulate the failing glands.
• Secondary (central) hypogonadism: the testicles are structurally normal, but they do not receive the right signals from the brain. The problem lies in the hypothalamus or the pituitary gland, two small structures at the base of the brain that control hormone production throughout the body. This type is also called hypogonadotropic hypogonadism.

Hypogonadism can be present from birth (congenital) or develop later in life (acquired). It can affect newborns, adolescents who fail to go through puberty, and adult men of any age. Testosterone levels also decline gradually as men grow older, and in some older men this decline becomes significant enough to cause symptoms and meet the criteria for hypogonadism. The condition is usually managed by hormone specialists working in an endocrinology and metabolism department, often together with urologists and fertility specialists when needed.

Symptoms of hypogonadism

Hypogonadism symptoms depend strongly on when in life the condition begins. Testosterone shapes the male body before birth, drives puberty in adolescence, and maintains muscle, bone, mood, and sexual function in adulthood. A shortage at each of these stages produces a different picture.

Symptoms when hypogonadism begins before or during puberty

• Delayed or absent puberty (no deepening of the voice, little facial and body hair)
• Poor development of muscle mass
• Small testicles and penis
• Disproportionately long arms and legs compared with the trunk, because the growth plates in the bones close late
• Development of breast tissue (gynecomastia)
• Little or no growth spurt compared with peers

Symptoms when hypogonadism begins in adulthood

• Reduced sexual desire (low libido)
• Erectile dysfunction, meaning difficulty getting or keeping an erection
• Fatigue and low energy
• Loss of muscle mass and strength
• Increased body fat, especially around the abdomen
• Decreased body and facial hair over time
• Low mood, irritability, or difficulty concentrating
• Reduced bone strength (osteoporosis), which raises the risk of fractures
• Infertility, meaning difficulty fathering a child
• Hot flashes in cases of severe hormone deficiency
• Breast tenderness or enlargement in some men

Many of these symptoms are nonspecific, which means they can also be caused by other conditions such as depression, thyroid disease, sleep disorders, or the natural effects of aging. This is one reason why hypogonadism should never be self-diagnosed and why blood tests are essential before any treatment is considered. Symptoms also tend to develop gradually in adult-onset cases, so men may attribute them to stress or age for years before seeking help.

In primary hypogonadism, symptoms may be accompanied by noticeably small or firm testicles. In secondary hypogonadism caused by a pituitary problem, additional symptoms can appear, such as headaches, vision changes, or signs of other hormone deficiencies, because the pituitary controls several hormone systems at once.

Causes and risk factors

Hypogonadism causes fall into two groups, matching the two types of the condition.

Causes of primary hypogonadism (testicular problem)

• Klinefelter syndrome: a genetic condition in which a boy is born with an extra X chromosome, which impairs testicular development. It is one of the most common congenital causes.
• Undescended testicles (cryptorchidism): testicles that did not move down into the scrotum before birth; if not corrected early, they may not function normally.
• Mumps orchitis: a mumps infection that involves the testicles, usually during adolescence or adulthood, can permanently damage them.
• Injury or torsion: physical trauma to the testicles, or twisting of the testicle that cuts off its blood supply.
• Cancer treatment: chemotherapy and radiation therapy can damage the cells in the testicles that produce testosterone and sperm. The damage is sometimes temporary but can be permanent.
• Surgical removal of the testicles, for example as part of cancer treatment.
• Excess iron (hemochromatosis): iron overload can injure both the testicles and the pituitary gland.
• Normal aging: testicular function declines gradually with age in many men.

Causes of secondary hypogonadism (brain-signaling problem)

• Kallmann syndrome: a congenital condition in which the hypothalamus does not develop normally; it is often accompanied by a reduced or absent sense of smell.
• Pituitary disorders: tumors (usually benign), surgery, or radiation involving the pituitary gland can reduce the signals that stimulate the testicles. A high level of the pituitary hormone prolactin can also suppress testosterone production.
• Inflammatory and infiltrative diseases: conditions such as sarcoidosis or tuberculosis can affect the hypothalamus and pituitary.
• Certain medications: long-term opioid painkillers and some hormonal treatments (for example, those used for prostate cancer) can suppress testosterone production. Previous use of anabolic steroids can have the same effect, sometimes lasting long after the steroids are stopped.
• Obesity: significant excess weight is strongly associated with lower testosterone levels.
• Serious illness and severe stress: major surgery, critical illness, extreme weight loss, or very intense physical training can temporarily lower hormone signals from the brain. This form is often reversible.
• HIV/AIDS and other chronic diseases: long-standing illness, including poorly controlled diabetes, kidney disease, and liver disease, can affect both the brain and the testicles.

Risk factors that make hypogonadism more likely include older age, obesity, type 2 diabetes, long-term opioid use, previous cancer treatment, a history of testicular problems in childhood, and a family history of genetic conditions such as Klinefelter or Kallmann syndrome.

Diagnosis

Hypogonadism diagnosis rests on two pillars: symptoms consistent with low testosterone and blood tests that confirm the deficiency. Doctors do not diagnose the condition on symptoms alone, and they do not treat a low blood value alone if the person has no symptoms.

Medical history and physical examination

The doctor will ask about sexual function, energy, mood, fertility, past illnesses and infections, medications, previous steroid use, and pubertal development. The physical examination typically includes an assessment of body hair, muscle mass, breast tissue, and the size and consistency of the testicles.

Blood tests

• Total testosterone: the key test. Because testosterone levels are highest in the morning and vary from day to day, the blood sample is usually taken in the morning, and a low result is generally confirmed with at least one repeat test on a different day.
• LH and FSH: these pituitary hormones (luteinizing hormone and follicle-stimulating hormone) signal the testicles to work. High levels suggest primary hypogonadism; low or inappropriately normal levels suggest secondary hypogonadism.
• Prolactin: checked when secondary hypogonadism is suspected, because a high prolactin level can suppress testosterone.
• Other tests as needed: free testosterone or sex hormone–binding globulin (a protein that carries testosterone in the blood), thyroid tests, iron studies to look for hemochromatosis, blood sugar, and a complete blood count.

Additional investigations

• Semen analysis: if fertility is a concern, a sperm count and quality assessment is often performed.
• Pituitary imaging (MRI): if blood tests point to a secondary cause, a magnetic resonance imaging scan of the brain may be ordered to look for pituitary or hypothalamic abnormalities.
• Genetic testing: a chromosome analysis (karyotype) can confirm Klinefelter syndrome when primary hypogonadism is found, especially in younger men.
• Bone density scan: because long-standing testosterone deficiency weakens bones, a scan may be recommended to check for osteoporosis.

Distinguishing primary from secondary hypogonadism matters, because the cause guides treatment, and because secondary hypogonadism can occasionally be the first sign of a pituitary tumor that needs attention in its own right.

Treatment options for hypogonadism

Hypogonadism treatment depends on the type, the cause, the person’s age, and whether fertility is a goal. Care is usually coordinated by an endocrinologist, a doctor who specializes in hormone disorders; at hospital groups such as Acibadem, this condition is managed within the endocrinology and metabolism specialty, often together with urology.

Treating the underlying cause

When hypogonadism has a reversible cause, addressing that cause comes first. Examples include stopping or replacing a medication that suppresses testosterone (where medically safe to do so), treating a high prolactin level with medication, managing iron overload, treating a pituitary tumor, losing excess weight, and controlling chronic diseases such as diabetes. In some of these situations, testosterone production recovers without hormone therapy.

Watchful waiting

Not every man with a borderline low testosterone level needs treatment. If symptoms are mild, if the low value may be temporary (for example, after an acute illness), or if lifestyle changes such as weight loss are likely to help, the doctor may recommend monitoring with repeat blood tests before starting any medication.

Testosterone replacement therapy

For men with confirmed, symptomatic hypogonadism, testosterone replacement therapy is the standard treatment. It aims to restore testosterone to a normal range and relieve symptoms such as low libido, fatigue, low mood, and loss of muscle and bone strength. Testosterone can be given in several forms:

• Gels or solutions applied to the skin daily
• Injections given into a muscle at intervals ranging from every one to two weeks to every few months, depending on the preparation
• Patches worn on the skin
• Other formulations, such as implanted pellets, nasal gels, or specific oral preparations, where available

Testosterone therapy requires ongoing medical supervision. Doctors typically monitor blood counts (because testosterone can raise red blood cell levels), prostate health, and hormone levels during treatment. Important cautions: testosterone therapy suppresses the body’s own sperm production, so it is generally not suitable for men who want to father a child in the near future, and it is usually avoided in men with prostate cancer, untreated severe sleep apnea, or certain heart and blood conditions. Your doctor will weigh the potential benefits and risks in your individual situation.

Fertility-oriented treatment

For men with secondary hypogonadism who wish to have children, doctors may use hormone injections such as human chorionic gonadotropin (hCG), sometimes combined with FSH, to stimulate the testicles to produce both testosterone and sperm. In some cases, other medications that boost the body’s own hormone signals are considered. Men with primary hypogonadism who have some remaining sperm production may be candidates for assisted reproduction techniques; a fertility specialist can advise on the options.

Treatment in adolescents

Boys with delayed puberty due to hypogonadism may be treated with carefully dosed testosterone to induce puberty, allowing development of adult body characteristics at an appropriate age. Treatment in adolescents requires specialist supervision to protect final adult height and normal development.

Surgery and procedures

Surgery is not a treatment for hypogonadism itself, but it may be needed for related conditions: removal or treatment of a pituitary tumor causing secondary hypogonadism, correction of undescended testicles in childhood, or, in selected cases, surgery for bothersome breast enlargement.

Living with hypogonadism and outlook

The outlook for hypogonadism is generally good when the condition is properly diagnosed and managed. Congenital and most primary forms are lifelong, and men with these forms usually need long-term hormone replacement; with consistent treatment and monitoring, many lead full, active lives. Some acquired forms, particularly those related to obesity, medications, or temporary illness, can improve or resolve when the underlying cause is addressed.

Living well with hypogonadism often involves more than medication:

• Regular follow-up: hormone levels, blood counts, and prostate health need periodic checks during testosterone therapy.
• Bone health: adequate calcium and vitamin D, weight-bearing exercise, and bone density monitoring help counter the fracture risk associated with long-standing testosterone deficiency.
• Healthy weight and exercise: losing excess weight and staying physically active support both hormone levels and overall health.
• Mental health: low testosterone can affect mood, and living with a chronic condition or fertility concerns can be emotionally difficult; support from a counselor or mental health professional can help.
• Fertility planning: men who may want children later should discuss options, including sperm preservation, before starting testosterone therapy.

Untreated, long-standing hypogonadism can contribute to osteoporosis, anemia, loss of muscle mass, and reduced quality of life, so ongoing care matters even when symptoms feel manageable. No treatment can guarantee complete symptom relief or restored fertility, but in many cases substantial improvement is achievable.

Frequently asked questions

What is hypogonadism in simple terms?

Hypogonadism means the sex glands, the testicles in men or the ovaries in women, do not make enough sex hormones. In men, this results in low testosterone, which can cause reduced sex drive, fatigue, loss of muscle and bone strength, and fertility problems. The problem can start in the glands themselves or in the brain centers that control them.

Can hypogonadism be cured?

It depends on the cause. Some forms, such as those linked to obesity, certain medications, temporary illness, or a treatable pituitary problem, can improve or resolve once the cause is addressed. Congenital forms and most primary testicular failure are lifelong conditions that cannot be cured, but they can usually be managed effectively with long-term hormone replacement under medical supervision.

How serious is hypogonadism?

Hypogonadism is rarely an immediate emergency, but it should not be ignored. Left untreated over years, low testosterone can weaken bones, reduce muscle mass, cause anemia, and affect mood, sexual function, and fertility. Occasionally, secondary hypogonadism is the first sign of a pituitary tumor, which is another reason a proper medical evaluation is important.

What are the most common hypogonadism symptoms in adult men?

The most common symptoms in adults are reduced sexual desire, erectile difficulties, persistent fatigue, low mood, loss of muscle strength, increased body fat, and, in some men, infertility or breast enlargement. Because these symptoms overlap with many other conditions, blood tests are needed to confirm whether low testosterone is actually the cause.

How is hypogonadism diagnosed?

Diagnosis usually starts with a discussion of symptoms and a physical examination, followed by a morning blood test measuring total testosterone, which is generally repeated to confirm a low result. Doctors also measure the pituitary hormones LH and FSH to determine whether the problem is in the testicles or the brain, and may order prolactin tests, a semen analysis, a pituitary MRI, or genetic testing depending on the findings.

Does testosterone treatment affect fertility?

Yes, this is an important point. Testosterone replacement therapy suppresses the body’s own sperm production while it is being used, so it is generally not recommended for men actively trying to father a child. Men with secondary hypogonadism who want children may instead be offered hormone injections that stimulate both testosterone and sperm production. Discuss fertility plans with your doctor before starting any hormone therapy.

Is low testosterone just a normal part of aging?

Testosterone levels do decline gradually with age in most men, and a modest decrease is normal. However, when the level falls clearly below the normal range and causes significant symptoms, this is considered hypogonadism rather than normal aging. Whether treatment is appropriate in older men is an individual decision that weighs symptoms, blood test results, and overall health, and should be made with a doctor.

When to see a doctor

Consider making an appointment with your doctor or an endocrinology specialist if you notice persistent symptoms suggestive of low testosterone, such as reduced sex drive, erectile difficulties, unexplained fatigue, loss of muscle strength, breast enlargement, or difficulty conceiving a child. Parents should seek evaluation for a boy whose puberty appears significantly delayed compared with his peers.

Seek prompt or urgent medical attention if any of the following red flags occur:

• Sudden, severe testicular pain, especially with swelling or nausea — this can indicate testicular torsion, a surgical emergency in which the testicle loses its blood supply
• A new lump, swelling, or hardness in a testicle, which always needs medical assessment
• Severe or worsening headaches together with vision changes (such as loss of side vision), which can signal a pituitary tumor
• Symptoms of low testosterone combined with signs of other hormone deficiencies, such as extreme tiredness, dizziness, low blood pressure, or unexplained weight loss
• A fragility fracture — a broken bone from a minor fall or bump — which may indicate significant bone loss
• Fever with painful testicular swelling, which may indicate an infection needing treatment

Early evaluation allows doctors to identify the cause of hypogonadism, rule out serious underlying conditions, and start appropriate treatment before complications such as bone loss develop.