Low testosterone (hypogonadism) - Symptoms, Causes, Treatment & Prevention

Overview

Low testosterone, medically termed hypogonadism, occurs when the testes (in men) or the hypothalamic‑pituitary axis fail to produce adequate amounts of testosterone. Testosterone is the primary male sex hormone and is essential for sexual development, bone density, muscle mass, mood, and red blood cell production.

While it can affect anyone with a testicle, the condition is most commonly diagnosed in men aged 30–70 years. Epidemiologic studies estimate that 2–5% of adult men have clinically significant hypogonadism, and the prevalence rises to > 20% in men over 60 years of age.¹

Both primary (testicular) and secondary (hypothalamic‑pituitary) forms exist, and the underlying cause can be genetic, medical, or lifestyle‑related.

Symptoms

Symptoms develop gradually and can be subtle. Below is a comprehensive list, grouped by body system.

Sexual Function

• Reduced libido: Decreased interest in sexual activity.
• Erectile dysfunction: Difficulty achieving or maintaining an erection.
• Decreased nocturnal erections: Fewer erections during sleep, a useful clinical clue.

Physical Changes

• Loss of muscle mass and strength: Noticeable weakness, especially in the upper body.
• Increased body fat: Often a higher waist‑to‑hip ratio; may lead to gynecomastia (breast tissue growth).
• Bone loss: Lower bone mineral density, raising the risk of fractures.
• Hot flashes & night sweats: Similar to menopausal symptoms in women.

Psychological / Cognitive

• Fatigue & low energy: Persistent tiredness not explained by other causes.
• Mood changes: Irritability, depression, or reduced sense of well‑being.
• Difficulty concentrating: “Brain fog,” reduced memory, slower mental processing.

General Health

• Anemia: Mild decrease in red blood cell count, leading to pallor or shortness of breath.
• Decreased facial/body hair: Slower hair growth, especially in the beard area.
• Sleep disturbances: Insomnia or frequent waking.

Causes and Risk Factors

Hypogonadism is classified based on the origin of the problem.

Primary (Testicular) Hypogonadism

• Klinefelter syndrome: Presence of an extra X chromosome (47,XXY).
• Mumps orchitis: Viral infection causing testicular inflammation.
• Testicular trauma or surgery: Injury, tumor removal, or radiation.
• Genetic mutations: e.g., androgen receptor defects.

Secondary (Hypothalamic‑Pituitary) Hypogonadism

• Age‑related decline: “Late‑onset hypogonadism” after 40‑45 years.
• Pituitary tumors or surgery: Can disrupt LH/FSH production.
• Chronic systemic illness: HIV, liver cirrhosis, chronic kidney disease.
• Obesity: Excess adipose tissue increases aromatase activity, converting testosterone to estradiol.
• Medications: Opioids, glucocorticoids, anabolic steroids, chemotherapy.

Risk Factors

• Age > 40 years.
• Body mass index (BMI) ≥ 30 kg/m².
• Type 2 diabetes or metabolic syndrome.
• History of testicular injury, infection, or surgery.
• Chronic use of opioids or glucocorticoids.
• Family history of early androgen deficiency.

Diagnosis

Diagnosing hypogonadism requires both clinical assessment and laboratory confirmation.

Clinical Evaluation

• Detailed medical, sexual, and medication history.
• Physical examination focusing on secondary sexual characteristics, testicular size, and body composition.

Laboratory Tests

1. Total testosterone: Morning (7–10 am) serum level; ≥ 300 ng/dL is generally considered normal.² Two separate measurements are recommended.
2. Free testosterone or bioavailable testosterone: Useful when SHBG (sex hormone‑binding globulin) is abnormal (e.g., obesity, liver disease).
3. Luteinizing hormone (LH) & Follicle‑stimulating hormone (FSH): Distinguish primary (high LH/FSH) from secondary (low/normal LH/FSH) causes.
4. Prolactin, thyroid‑stimulating hormone (TSH), and cortisol: To rule out other endocrine disorders.
5. Hemoglobin/hematocrit, lipid profile, fasting glucose: Baseline for treatment monitoring.

Imaging & Additional Tests

• Scrotal ultrasound: Evaluates testicular size and vascular flow.
• Pituitary MRI: Indicated if secondary hypogonadism is suspected and a pituitary lesion is possible.

Treatment Options

Treatment is individualized, aiming to restore physiological testosterone levels, alleviate symptoms, and address the underlying cause.

Testosterone Replacement Therapy (TRT)

• Intramuscular injections: Testosterone cypionate or enanthate every 1–2 weeks.
• Transdermal gels/patches: Daily application; convenient but risk of skin irritation.
• Subdermal pellets: Implanted every 3–6 months; provides steady release.
• Oral formulations: E.g., testosterone undecanoate (limited use due to liver toxicity risk).

Guidelines from the Endocrine Society recommend aiming for a mid‑normal serum testosterone range (400–700 ng/dL) and monitoring every 3–6 months for efficacy and safety.³

Adjunct Medications

• Selective estrogen receptor modulators (SERMs): Clomiphene or tamoxifen can stimulate endogenous testosterone in men with secondary hypogonadism.
• Aromatase inhibitors: Anastrozole reduces conversion of testosterone to estradiol, useful in obese men.
• Human chorionic gonadotropin (hCG): Mimics LH, preserving fertility while boosting testosterone.

Lifestyle Interventions

• Weight loss (5–10% body weight) can raise testosterone by 10–15% in obese men.⁴
• Resistance training 3×/week improves muscle mass and endogenous testosterone.
• Adequate sleep (7–9 h/night) and stress reduction (mindfulness, CBT).
• Limit alcohol (<2 drinks/day) and avoid illicit drugs.
• Review medications with your physician; consider alternatives to chronic opioids.

Surgical/Procedural Options

• Pituitary tumor removal if a lesion is causing secondary hypogonadism.
• Testicular sperm extraction (TESE) for men desiring fertility while on TRT.

Living with Low Testosterone (Hypogonadism)

Effective management extends beyond medication.

Daily Management Tips

• Track symptoms: Use a simple diary or mobile app to note energy, mood, and sexual function.
• Adhere to dosing schedule: Set alarms for injections or gel application.
• Monitor labs: Keep a copy of recent testosterone, PSA, hemoglobin, and lipid results.
• Stay active: Combine aerobic (30 min, 5 days/week) with strength training.
• Nutrition: Emphasize zinc‑rich foods (lean meat, pumpkin seeds), vitamin D, and healthy fats.
• Maintain healthy weight: Even modest weight loss improves hormone balance.
• Communicate with partners: Discuss sexual concerns openly; counseling can be helpful.

Fertility Considerations

Exogenous testosterone can suppress spermatogenesis. Men who wish to preserve fertility should discuss hCG or SERMs with their doctor before starting TRT.

Psychosocial Support

Depression and low self‑esteem are common. Referral to mental‑health professionals, support groups, or counseling services is advised when mood symptoms persist.

Prevention

While age‑related decline cannot be avoided, many modifiable factors influence testosterone levels.

• Maintain a healthy weight: Target a BMI < 25 kg/m².
• Exercise regularly: Both aerobic and resistance training support endocrine health.
• Balanced diet: Adequate protein, healthy fats, and micronutrients (zinc, vitamin D, magnesium).
• Limit exposure to endocrine disruptors: Reduce use of BPA‑containing plastics, avoid excessive soy isoflavones, and use protective equipment when handling pesticides.
• Avoid chronic high-dose opioids and excessive alcohol.
• Screen for and treat chronic diseases (diabetes, sleep apnea, thyroid disorders) early.

Complications

If left untreated, low testosterone can lead to serious health issues.

• Osteoporosis and fractures: Up to 30% of untreated men develop low bone mineral density.
• Cardiovascular disease: Some studies link low testosterone with atherosclerosis, though data are mixed; ongoing research is evaluating risk‑benefit of TRT.
• Metabolic syndrome: Worsening insulin resistance and dyslipidemia.
• Anemia: Persistent low hemoglobin may require transfusion.
• Psychological sequelae: Depression, reduced quality of life, and marital strain.
• Reduced muscle mass leading to falls and disability in older adults.

When to Seek Emergency Care

Sources:

1. Mayo Clinic. Male hypogonadism (low testosterone). Accessed May 2026.
2. Centers for Disease Control and Prevention. Testosterone deficiency. Accessed May 2026.
3. Endocrine Society Clinical Practice Guideline: Testosterone Therapy in Adult Men with Hypogonadism. 2022.
4. Cleveland Clinic. Hypogonadism (Low Testosterone). Accessed May 2026.