Hypogonadism

Quick takeaways

• Hypogonadism means the body is not making enough sex hormones; in men, this usually refers to low testosterone and sometimes impaired sperm production.
• Symptoms can include low sex drive, erectile dysfunction, fatigue, reduced morning erections, loss of muscle, mood changes, infertility, and reduced body hair.
• There are two broad types: primary hypogonadism (a testicular problem) and secondary hypogonadism (a signaling problem involving the pituitary or hypothalamus).
• A single low testosterone value is usually not enough to make the diagnosis; doctors typically look for symptoms plus repeated morning blood tests.
• Hypogonadism can affect fertility by lowering sperm production, but the impact depends on the cause and the treatment used.
• Testosterone replacement therapy can improve symptoms in some men, but it can also suppress sperm production and may not be appropriate for men trying to conceive.
• Treatment should target the cause when possible and may include specialist evaluation, medication changes, weight loss, treating sleep apnea, fertility-preserving hormone therapy, or testosterone therapy when appropriate.
• If symptoms are significant, fertility is a concern, or blood tests are abnormal, professional evaluation is important.

What is hypogonadism?

In men, hypogonadism refers to insufficient testicular hormone production, usually leading to testosterone levels that are too low for the body’s needs. The term may also imply reduced production of sperm because both functions are closely tied to testicular health and hormonal signaling.

Testosterone is made mainly in the testes under the control of two hormones released by the pituitary gland: luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The pituitary itself is regulated by the hypothalamus in the brain through gonadotropin-releasing hormone (GnRH). This is often called the hypothalamic-pituitary-gonadal axis or HPG axis.

If any part of this system is disrupted, testosterone can fall and symptoms may develop. That is why hypogonadism is more than “just low T.” The diagnosis depends on the whole clinical picture: symptoms, history, exam, repeated lab testing, and in some cases imaging or additional endocrine workup.

Common alternate terms

• Male hypogonadism
• Low testosterone due to gonadal dysfunction
• Androgen deficiency, in some contexts
• Testosterone deficiency, when specifically referring to low testosterone with symptoms

These terms overlap but are not always interchangeable. “Low testosterone” describes a lab result, while “hypogonadism” is a broader medical diagnosis.

Why hypogonadism matters in men’s health and fertility

Hypogonadism matters because testosterone supports far more than sexual function. Low testosterone can affect:

• Sexual health: sex drive, arousal, erectile quality, and frequency of morning erections
• Fertility: sperm production and testicular function
• Body composition: muscle mass, fat distribution, and strength
• Bone health: bone mineral density and fracture risk over time
• Mood and cognition: motivation, concentration, mood, and sense of well-being
• Energy: fatigue, reduced stamina, and slower recovery
• Metabolic health: insulin resistance, obesity, and chronic inflammation can both contribute to and worsen low testosterone

For men trying to conceive, hypogonadism is especially important because some causes directly impair sperm production, and some treatments for low testosterone can unexpectedly reduce or stop sperm production. That is a major reason fertility goals should always be part of the conversation before treatment starts.

Types of hypogonadism

Doctors generally divide hypogonadism into two main categories based on where the problem starts.

Primary hypogonadism

In primary hypogonadism, the testes do not respond normally even though the brain may be sending stronger signals to stimulate them. Because the body is trying to compensate, LH and FSH often rise.

Secondary hypogonadism

In secondary hypogonadism, the testes may be structurally capable of working, but the pituitary or hypothalamus is not giving them sufficient stimulation. LH and FSH are often low or “normal” in a way that is inappropriate for the low testosterone level.

Congenital vs acquired hypogonadism

Hypogonadism can also be described by when it begins:

• Congenital: present from birth, often due to genetic or developmental conditions
• Acquired: develops later due to weight gain, illness, medications, aging, pituitary disease, trauma, infection, or testicular damage

Causes of hypogonadism

The causes of hypogonadism vary widely. Some are reversible, some are chronic, and some require urgent evaluation.

Causes of primary hypogonadism

• Genetic conditions such as Klinefelter syndrome
• Undescended testicles or testicular developmental problems
• Testicular injury or torsion
• Infections affecting the testes, including mumps orchitis
• Chemotherapy or radiation
• Testicular surgery
• Autoimmune or inflammatory damage, in some cases
• Varicocele may affect testicular function in some men, although it more often relates to fertility than clear-cut hypogonadism

Causes of secondary hypogonadism

• Obesity, which can suppress the HPG axis and lower testosterone
• Pituitary disorders, including tumors, inflammation, trauma, surgery, or prior radiation
• Hyperprolactinemia (high prolactin)
• Severe stress, excessive exercise, or undernutrition
• Chronic systemic illness
• Sleep apnea
• Medications, especially opioids, glucocorticoids, some psychotropic drugs, and exogenous testosterone or anabolic steroids
• Anabolic steroid use, which can strongly suppress natural testosterone and sperm production
• Hemochromatosis and other infiltrative diseases affecting the pituitary
• Rare genetic causes, including Kallmann syndrome and certain GnRH or pituitary disorders

Aging and “functional” hypogonadism

Testosterone levels tend to decline gradually with age, but age alone is not enough to diagnose hypogonadism. Many older men maintain normal levels. In practice, low testosterone in midlife is often linked not just to aging itself, but to weight gain, poor sleep, metabolic disease, inflammation, medications, and reduced physical activity. Some experts describe this as functional hypogonadism when the hormonal suppression may improve if the underlying drivers are addressed.

Symptoms and signs of hypogonadism

Symptoms can be subtle, vary from person to person, and overlap with other conditions like depression, thyroid disease, chronic stress, poor sleep, or medication side effects. Common symptoms include:

• Low libido or reduced sexual desire
• Erectile dysfunction or weaker erections
• Fewer spontaneous or morning erections
• Fatigue or low energy
• Reduced muscle mass or strength
• Increased body fat, especially central fat
• Low mood, irritability, or reduced motivation
• Difficulty concentrating
• Decreased shaving frequency or reduced body/facial hair over time
• Infertility or low sperm count
• Hot flashes, especially in more severe androgen deficiency
• Low bone density or fractures
• Testicular shrinkage in some cases
• Gynecomastia, or enlarged breast tissue

Symptoms can depend on age of onset

If hypogonadism begins before puberty, it may delay or alter normal pubertal development, including genital growth, body hair, voice deepening, and muscle development. When it begins in adulthood, sexual symptoms, low energy, fertility problems, and body composition changes are more common.

What’s normal vs what’s not?

There is no single testosterone number that explains every case. Testosterone fluctuates during the day, is often highest in the morning, and can be influenced by sleep, illness, medications, weight, and lab methods. That is why a diagnosis usually requires both symptoms and confirmatory testing.

How testosterone is typically interpreted

• Normal total testosterone: depends on the lab and assay, but many labs report adult reference ranges roughly in the low hundreds to upper hundreds of ng/dL.
• Borderline low levels: may need repeat testing and context, especially if symptoms are mild or non-specific.
• Clearly low levels: if confirmed on repeat morning testing and paired with symptoms, they are more suggestive of hypogonadism.

Some men have symptoms with borderline total testosterone because of changes in sex hormone-binding globulin (SHBG), which affects how much testosterone is free or bioavailable. In those cases, clinicians may order free testosterone or use calculations based on total testosterone, SHBG, and albumin.

One blood test is usually not enough

Because testosterone changes throughout the day, doctors commonly repeat testing on a separate morning sample, especially if the first result is low or borderline. If the result is unexpected, they may also check whether sleep loss, illness, calorie restriction, recent steroid use, or medication effects could have contributed.

How hypogonadism is diagnosed

Diagnosing hypogonadism means finding out whether testosterone is truly low, whether symptoms fit, and why the issue is happening. That often involves more than one blood test.

Typical diagnostic steps

1. Review symptoms and history
   Doctors ask about sexual function, libido, fertility, energy, mood, puberty history, medications, anabolic steroid use, weight changes, sleep apnea, and chronic illness.
2. Physical examination
   This may include body hair pattern, breast tissue, body composition, testicular size, signs of pituitary disease, and blood pressure.
3. Morning total testosterone testing
   Usually done early in the day, and repeated if low or borderline.
4. LH and FSH testing
   These help distinguish primary from secondary hypogonadism.
5. Additional blood work when indicated
   May include free testosterone, SHBG, prolactin, estradiol, thyroid testing, iron studies, CBC, liver function, and metabolic markers.
6. Imaging or specialist workup in selected cases
   Pituitary MRI may be considered if there are signs of pituitary disease, very low gonadotropins, headaches, visual symptoms, or high prolactin.
7. Semen analysis if fertility matters
   This is essential if the man is trying to conceive or concerned about sperm health.

Tests commonly used in evaluation

What do LH and FSH tell you?

These hormones act like clues:

• High LH/FSH with low testosterone: suggests the brain is trying to stimulate the testes, but the testes are not responding well. This points more toward primary hypogonadism.
• Low or normal LH/FSH with low testosterone: suggests the pituitary or hypothalamus is not signaling properly. This points more toward secondary hypogonadism.

How hypogonadism affects sperm and fertility

Hypogonadism can affect fertility in several ways. Testosterone produced inside the testes is essential for normal sperm production, and the pituitary hormones LH and FSH are also critical. If this hormonal system is disrupted, sperm concentration, motility, and overall semen quality may decline.

Possible fertility effects

• Low sperm count or oligospermia
• Complete absence of sperm in semen, called azoospermia, in more severe cases
• Reduced sperm motility
• Smaller testicular volume in some conditions
• Reduced libido and sexual frequency, which can indirectly affect conception chances

Important warning: testosterone therapy can reduce sperm production

This is one of the most misunderstood issues in men’s reproductive health. External testosterone—including injections, gels, pellets, patches, and some “testosterone boosting” prescription regimens—can signal the brain to reduce LH and FSH production. When that happens, the testes receive less stimulation and may make less sperm or no sperm at all.

For men actively trying to conceive, standard testosterone replacement therapy is often the wrong treatment, even if testosterone is low. Fertility-preserving options may include treating the cause, stopping suppressive medications, or using other hormone-based therapies under specialist supervision.

Fertility-preserving treatment approaches

Depending on the cause, age, and lab profile, treatment may involve:

• Selective estrogen receptor modulators such as clomiphene citrate, in selected men
• Human chorionic gonadotropin (hCG) to stimulate intratesticular testosterone production
• FSH-containing therapy in certain forms of secondary hypogonadism
• Treating reversible causes like obesity, sleep apnea, hyperprolactinemia, or medication-related suppression
• Stopping anabolic steroids or exogenous testosterone when medically appropriate, with supervised recovery planning

Men who care about fertility should ideally be evaluated by a clinician familiar with male reproductive endocrinology or male infertility before starting any hormone treatment.

Treatment options for hypogonadism

Treatment depends on the cause, the severity of symptoms, lab results, age, and whether fertility is a goal. The right treatment for one man may be the wrong treatment for another.

1. Treat the underlying cause when possible

This is often the most important step. Examples include:

• Weight loss and treatment of obesity-related hypogonadism
• Treating sleep apnea
• Addressing high prolactin levels
• Reviewing opioids, steroids, or other suppressive medications
• Managing chronic illness and improving metabolic health
• Stopping anabolic steroids, with medical support if needed

2. Testosterone replacement therapy (TRT)

TRT can improve symptoms in properly selected men with confirmed hypogonadism, but it is not appropriate for everyone. Potential benefits may include improved libido, mood, energy, muscle mass, and bone density, though response varies.

Common forms include:

• Injections
• Transdermal gels
• Patches
• Pellets
• Other specialist-directed formulations

Potential risks and monitoring with TRT

TRT requires follow-up because it can affect more than testosterone. Monitoring may include:

• Symptom response
• Testosterone levels
• Hematocrit or hemoglobin, because TRT can raise red blood cell levels
• Prostate-related monitoring when age and clinical context warrant it
• Estradiol in selected cases
• Sleep apnea symptoms, blood pressure, and cardiovascular risk factors

TRT can also suppress sperm production, so it is usually avoided if a man wants near-term fertility.

3. Fertility-preserving medical therapy

In men who want to maintain or improve fertility, doctors may consider treatments that stimulate the body’s own hormone axis rather than replacing testosterone from the outside. These therapies are more individualized and should be supervised by a qualified clinician.

4. Puberty induction or specialized endocrine care

For adolescents or men with congenital forms of hypogonadism, treatment may involve puberty induction, long-term hormone support, fertility planning, bone health monitoring, and genetic or reproductive counseling.

Treatment comparison

Lifestyle factors and natural support

Lifestyle is not a cure for every type of hypogonadism, but it can make a meaningful difference, especially when low testosterone is related to obesity, poor sleep, metabolic dysfunction, or medication effects.

What may help support testosterone naturally

• Reach a healthier body weight, especially if central obesity is present
• Prioritize sleep and evaluate for sleep apnea when symptoms suggest it
• Resistance training and regular physical activity
• Adequate calorie and protein intake, avoiding extreme dieting when possible
• Limit heavy alcohol use
• Avoid anabolic steroids and unregulated “boosters”
• Manage diabetes, metabolic syndrome, and chronic medical conditions
• Review medications with a clinician

Can supplements fix hypogonadism?

Usually not, at least not in a reliable or evidence-based way. Some men with nutritional deficiencies may benefit from correcting those deficiencies, but over-the-counter “testosterone boosters” are often over-marketed and may not meaningfully raise testosterone. Some products are poorly regulated and may even contain undeclared ingredients. If symptoms and testing suggest true hypogonadism, medical evaluation is more useful than self-treating with supplements.

Common myths and misconceptions

Myth: Low testosterone and hypogonadism are exactly the same thing

Not quite. A low lab value can happen temporarily or in isolation. Hypogonadism is a clinical diagnosis that usually requires symptoms plus confirmed low testosterone and proper evaluation.

Myth: If you feel tired, you probably have low T

Not necessarily. Fatigue is common and non-specific. Poor sleep, stress, depression, thyroid disease, anemia, medication side effects, and many other issues can cause similar symptoms.

Myth: Testosterone therapy improves fertility

Often the opposite. Exogenous testosterone can suppress sperm production and may significantly reduce fertility.

Myth: More testosterone is always better

No. Hormone treatment should aim for appropriate levels and symptom control, not excessive dosing. Over-treatment can raise risks and create new problems.

Myth: Hypogonadism only affects older men

False. It can affect adolescents, young adults, and middle-aged men, especially with genetic conditions, pituitary disorders, medication effects, obesity, or prior anabolic steroid use.

Questions to ask your doctor

If you are being evaluated for hypogonadism, these questions can help guide the conversation:

• Do my symptoms and lab results actually fit hypogonadism?
• Was my testosterone tested at the right time of day, and should it be repeated?
• Is this more likely primary or secondary hypogonadism?
• Should I have LH, FSH, prolactin, free testosterone, or SHBG checked?
• Could obesity, sleep apnea, stress, illness, or medications be contributing?
• Do I need a semen analysis if I want children?
• Would testosterone therapy affect my fertility?
• Are there fertility-preserving treatment options in my case?
• What monitoring would I need if treatment starts?
• Should I see an endocrinologist or male fertility specialist?

Related tests and terms

• Testosterone: the main androgen hormone measured in evaluation
• Free testosterone: the portion not tightly bound to proteins
• LH (luteinizing hormone): pituitary hormone that stimulates testicular testosterone production
• FSH (follicle-stimulating hormone): pituitary hormone important for sperm production
• SHBG: protein that binds testosterone and influences interpretation of total levels
• Prolactin: elevated levels can suppress reproductive hormones
• Semen analysis: basic fertility test that evaluates sperm count, motility, volume, and more
• Azoospermia: no sperm seen in the ejaculate
• Oligospermia: low sperm concentration
• TRT: testosterone replacement therapy
• Gynecomastia: enlarged male breast tissue, which can occur with hormonal imbalance
• HPG axis: the hormonal communication system linking the brain and testes

When to seek medical advice

It is worth speaking with a healthcare professional if you have ongoing symptoms such as low libido, persistent erectile difficulty, infertility, marked fatigue, reduced morning erections, hot flashes, loss of body hair, or unexplained reductions in muscle mass or bone density.

Prompt evaluation is especially important if you have:

• Infertility or abnormal semen analysis results
• Very small testes, delayed puberty, or absent pubertal development
• Headaches, vision changes, or nipple discharge, which can suggest pituitary issues
• A history of anabolic steroid use
• Prior chemotherapy, radiation, testicular trauma, or undescended testes
• Symptoms severe enough to affect relationships, work, or quality of life

Frequently asked questions

Is hypogonadism the same as low testosterone?

Not exactly. Low testosterone is a laboratory finding. Hypogonadism is a diagnosis based on symptoms, repeated hormone testing, and determining whether there is a problem in the testes or the hormone control system.

Can hypogonadism cause infertility?

Yes. It can impair sperm production directly or indirectly, depending on the cause. Some men have low testosterone and low sperm counts, while others may have fertility problems even with testosterone levels that are only mildly reduced.

Can you have normal testosterone and still have fertility problems?

Yes. A man can have normal testosterone but abnormal sperm production for other reasons, including varicocele, genetic issues, infection, obstruction, heat exposure, or unexplained male factor infertility.

What is secondary hypogonadism?

Secondary hypogonadism happens when the pituitary or hypothalamus does not send enough hormonal stimulation to the testes. Obesity, pituitary disorders, high prolactin, medications, severe illness, and anabolic steroid suppression are common examples.

Can obesity cause hypogonadism?

Yes. Obesity is a common contributor to lower testosterone and can suppress the body’s normal reproductive hormone signaling. Weight loss may improve testosterone in some men, though not every case fully normalizes.

Does testosterone replacement therapy improve sperm count?

Usually no. Standard testosterone replacement often lowers sperm count and can even lead to azoospermia. Men trying to conceive should discuss fertility-safe alternatives before starting treatment.

Can hypogonadism be reversed?

Sometimes. Reversible causes such as obesity, medication effects, sleep apnea, high prolactin, or anabolic steroid suppression may improve with appropriate treatment. Genetic or permanent testicular damage may not be reversible.

How is hypogonadism diagnosed?

Diagnosis commonly involves symptoms plus at least two morning testosterone tests, along with LH and FSH and other labs when needed. A semen analysis is often added when fertility is a concern.

Is hypogonadism common with aging?

Testosterone often declines somewhat with age, but clinically important hypogonadism is not just a normal part of aging. Other treatable factors such as obesity, medication use, sleep problems, and chronic illness often play a major role.

Should I see an endocrinologist or a fertility specialist?

If the diagnosis is unclear, if pituitary disease is possible, or if hormone management is complex, an endocrinologist may help. If fertility or sperm production is a major concern, a male fertility specialist or reproductive urologist can be especially valuable.

References

• Endocrine Society Clinical Practice Guideline: Testosterone Therapy in Men With Hypogonadism.
• American Urological Association (AUA) Guideline on Testosterone Deficiency.
• European Association of Urology (EAU) Guidelines on Sexual and Reproductive Health.
• American Society for Reproductive Medicine (ASRM) guidance on male infertility and reproductive hormones.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Overview of hypogonadism and endocrine disorders.
• Merck Manual Professional Edition: Male hypogonadism.
• StatPearls: Male Hypogonadism and related endocrine review articles.