ANDROPAUSE / LATE-ONSET MALE HYPOGONADISM

Etymology, Pathophysiology, Modern Endocrinological Diagnosis, Hormonal Therapy, Cardiovascular Controversies, and Referral Criteria to Urology and Endocrinology

Advanced Medical-Scientific Review Updated 2026

By DrRamonReyesMD ⚕️

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ETYMOLOGY AND MEDICAL TERMINOLOGY

The term:

“ANDROPAUSE”

derives from the Greek:

“ANDROS” (ἀνήρ / ANDRÓS) = man, male.

“PAUSIS” (παῦσις) = cessation, interruption.

Literally:

“male cessation.”

However:

from a modern endocrinological perspective, the term is imperfect.

Why?

Because:

men do NOT experience an abrupt and universal cessation of gonadal function comparable to female menopause.

Menopause involves:

relatively abrupt ovarian follicular depletion,

dramatic estrogen decline,

universal physiological infertility.

In contrast, men:

may maintain androgen production into advanced age,

often preserve partial fertility,

and exhibit an extremely heterogeneous hormonal decline.

Therefore, modern scientific societies prefer more precise terminology:

male hypogonadism,

testosterone deficiency syndrome,

LOH (Late-Onset Hypogonadism),

or testosterone deficiency syndrome.

Current guidelines from the:

European Association of Urology (EAU),

American Urological Association (AUA),

and the Endocrine Society

agree on a critical point:

“andropause” is NOT diagnosed solely based on fatigue or aging.

Diagnosis requires:

compatible symptoms + biochemically confirmed low testosterone.

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PHYSIOLOGY OF THE HYPOTHALAMIC–PITUITARY–GONADAL AXIS

Testosterone is primarily synthesized by:

testicular Leydig cells.

Endocrine regulation:

Hypothalamus → GnRH (Gonadotropin-Releasing Hormone) → Anterior Pituitary → LH / FSH → Testis.

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PHYSIOLOGICAL FUNCTIONS OF TESTOSTERONE

Testosterone is involved in:

libido,

nocturnal erections,

erectile function,

spermatogenesis,

bone mineral density,

erythropoiesis,

muscle mass,

fat distribution,

glucose metabolism,

insulin sensitivity,

cognition,

motivation,

energy,

emotional regulation.

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AGING AND TESTOSTERONE

After the fourth decade:

total testosterone declines approximately 0.8–1.5% annually.

Free testosterone declines even faster due to increasing:

SHBG (Sex Hormone-Binding Globulin).

However:

aging does NOT automatically equal endocrine disease.

Many elderly men:

maintain functional testosterone levels,

partial fertility,

and preserved sexual function.

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PATHOPHYSIOLOGY OF MALE HYPOGONADISM

PRIMARY HYPOGONADISM (HYPERGONADOTROPIC)

Testicular gonadal failure.

Biochemical characteristics:

low testosterone,

elevated LH,

elevated FSH.

Etiologies include:

,

viral orchitis,

chemotherapy,

radiotherapy,

testicular trauma,

torsion,

gonadal aging,

.

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SECONDARY HYPOGONADISM (HYPOGONADOTROPIC)

Hypothalamic or pituitary dysfunction.

Characteristics:

low testosterone,

low or inappropriately normal LH/FSH.

Common etiologies:

visceral obesity,

obstructive sleep apnea,

,

opioids,

corticosteroids,

hyperprolactinemia,

pituitary adenomas,

systemic diseases,

chronic stress,

severe energy deficit.

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METABOLIC SYNDROME AS A GONADAL SUPPRESSOR

Visceral obesity promotes:

peripheral aromatization of testosterone → estradiol,

chronic inflammation,

insulin resistance,

hypothalamic dysfunction,

LH suppression.

Therefore:

many modern “LOW T” cases are metabolic rather than purely gonadal.

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THE MODERN PROBLEM: THE “LOW T INDUSTRY”

There is currently:

aggressive commercial medicalization of androgen deficiency.

Particularly driven by:

digital marketing,

anti-aging clinics,

fitness influencers,

male cosmetic medicine,

TRT used for performance enhancement.

This has generated:

overdiagnosis,

unnecessary TRT,

endocrine trivialization,

psychological dependence on therapy.

Several recent publications criticize the creation of a commercially marketed pseudo-pathology of male aging.

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CLINICAL MANIFESTATIONS

SEXUAL

decreased libido,

loss of morning erections,

erectile dysfunction,

infertility,

reduced sexual frequency.

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PHYSICAL

loss of muscle mass,

increased visceral adiposity,

osteoporosis,

osteopenia,

fatigue,

reduced strength,

anemia.

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NEUROPSYCHIATRIC

apathy,

depression,

irritability,

impaired concentration,

brain fog,

sleep disturbances,

reduced motivation.

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THE DIAGNOSTIC CHALLENGE

These symptoms are:

highly nonspecific.

They may result from:

depression,

burnout,

stress,

sleep apnea,

diabetes,

obesity,

alcohol use,

hypothyroidism,

systemic illness,

physiological aging.

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MODERN DIAGNOSIS IN 2026

FUNDAMENTAL RULE

A single testosterone value is NOT sufficient.

The recommends:

morning testosterone measurement,

between 07:00–11:00,

fasting state,

confirmation in TWO separate samples.

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IMPORTANT THRESHOLDS

EAU

Total testosterone:

<12 nmol/L

as a symptom-associated reference threshold.

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AUA

<300 ng/dL

as a reasonable diagnostic threshold.

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RECOMMENDED LABORATORY WORKUP

Before TRT:

total testosterone,

calculated free testosterone,

SHBG,

LH,

FSH,

prolactin,

TSH,

PSA,

complete blood count,

glucose/HbA1c,

lipid profile,

liver function,

ferritin if hemochromatosis is suspected.

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WHEN TO SUSPECT PITUITARY PATHOLOGY

Particularly if:

extremely low testosterone,

low LH,

headache,

galactorrhea,

visual disturbances,

hyperprolactinemia.

In such cases:

pituitary MRI is mandatory.

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TESTOSTERONE REPLACEMENT THERAPY (TRT)

Indicated ONLY in:

confirmed hypogonadism + clinically significant symptoms.

NOT:

“to feel younger,”

or for gym performance enhancement.

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PHARMACOLOGICAL FORMS

1. TRANSDERMAL GEL

Examples:

Advantages:

more physiological levels,

easy dose adjustment.

Limitations:

cutaneous transfer,

adherence issues,

variable absorption.

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2. INTRAMUSCULAR TESTOSTERONE UNDECANOATE

Typical European regimen:

initial dose,

second dose approximately 6 weeks later,

then every 10–14 weeks.

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3. ENANTHATE / CYPIONATE

More commonly used in the United States.

Problems:

hormonal peaks and troughs,

mood and metabolic fluctuations.

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POTENTIAL BENEFITS OF TRT

TRT may improve:

libido,

sexual function,

energy,

body composition,

bone density,

anemia,

muscle mass.

DOI: 10.1210/jc.2018-00229

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IMPORTANT RISKS

1. POLYCYTHEMIA

One of the most relevant complications.

Monitor:

hematocrit.

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2. INFERTILITY

TRT suppresses the gonadal axis.

It decreases:

FSH,

LH,

spermatogenesis.

Particularly important in younger men.

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3. OBSTRUCTIVE SLEEP APNEA

May worsen significantly.

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4. FLUID RETENTION

Use caution in:

heart failure,

hypertension,

elderly patients.

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5. PROSTATE

Current evidence does NOT demonstrate a clear increase in prostate cancer risk with properly monitored TRT.

However:

PSA,

digital rectal examination,

and urological surveillance

remain essential.

DOI: 10.1016/j.eururo.2025.03.032

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MONITORING

Monitor:

testosterone,

PSA,

hematocrit,

metabolic profile,

blood pressure,

symptoms,

weight.

Follow-up:

initially at 3 months,

then every 6–12 months.

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ERECTILE DYSFUNCTION AND TESTOSTERONE

Important:

NOT all erectile dysfunction is androgenic.

Most cases are:

vascular,

metabolic,

psychological,

or pharmacological.

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ASSOCIATED MEDICATIONS

PDE5 Inhibitors

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FERTILITY-PRESERVING THERAPIES

In patients wishing to preserve fertility, clinicians often prefer:

HCG,

clomiphene,

gonadotropins

instead of direct TRT.

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WHEN TO REFER TO UROLOGY

Referral is recommended in cases of:

confirmed low testosterone,

significant sexual symptoms,

infertility,

complex erectile dysfunction,

abnormal PSA,

testicular mass,

significant gynecomastia,

TRT failure,

suspected malignancy,

elevated hematocrit,

young patients.

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WHEN TO REFER TO ENDOCRINOLOGY

Particularly in cases of:

hyperprolactinemia,

suspected pituitary disease,

secondary hypogonadism,

complex obesity/metabolic dysfunction,

multiple endocrine abnormalities.

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CONCLUSIONS

The condition commonly referred to as “andropause” represents a multidimensional process involving:

aging,

metabolism,

sleep,

endocrinology,

vascular health,

mental health,

and gonadal function.

The major modern mistake is:

labeling any male fatigue syndrome as “LOW T.”

TRT can dramatically improve quality of life in appropriately selected patients.

However, it may also lead to:

infertility,

polycythemia,

therapeutic dependence,

overtreatment,

unnecessary medicalization.

Evidence-based modern medicine requires:

accurate biochemical diagnosis,

rigorous etiological evaluation,

precise patient selection,

strict monitoring,

and appropriate specialist referral.

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SCIENTIFIC REFERENCES

European Association of Urology

American Urological Association

Endocrine Society

KEY DOI REFERENCES

Bhasin S et al. Testosterone Therapy in Men With Hypogonadism.
DOI: 10.1210/jc.2018-00229

Mulhall JP et al. Evaluation and Management of Testosterone Deficiency.
DOI: 10.1016/j.juro.2018.03.115

Salonia A et al. EAU 2025 Update on Male Hypogonadism.
DOI: 10.1016/j.eururo.2025.03.032