What testosterone deficiency syndrome is
Testosterone deficiency syndrome (TDS) — sometimes called late-onset hypogonadism or androgen deficiency in the aging male (ADAM) — is defined by the combination of:
- Clinical symptoms consistent with testosterone deficiency
- Biochemical evidence of low testosterone (by total testosterone, free testosterone, or both)
The requirement for both clinical and biochemical criteria is important. Laboratory evidence alone, without symptoms, typically does not warrant treatment. Symptoms without biochemical support likewise do not confirm the diagnosis. TDS is a clinical-biochemical syndrome, not a laboratory result.
The prevalence in Indian men
The landmark 2019 study by Yadav et al. at Sir Ganga Ram Hospital, New Delhi, evaluated 110 Indian men aged 40 and above with metabolic syndrome. They found:
- 48.18% met symptomatic criteria for TDS
- 28.99% had both symptomatic and biochemical confirmation
These figures are strikingly higher than prevalence estimates from Western studies, which typically range from 5–12% in men aged 40–79. The difference likely reflects India's high burden of metabolic comorbidities — insulin resistance, diabetes, hypertension, and obesity — which independently suppress testosterone.
The association between TDS and metabolic syndrome was strong: men with more metabolic risk factors had higher rates of testosterone deficiency. This is consistent with the bidirectional relationship between testosterone and metabolic health.
The symptom spectrum
TDS symptoms fall into three categories:
Sexual symptoms. Reduced libido (reduced sexual interest or desire) is the most sensitive symptom — it is present in the majority of symptomatic TDS patients. Erectile dysfunction (particularly reduced nocturnal and morning erections) and reduced ejaculatory volume are also common. These are the symptoms most patients recognise and are most likely to report.
Physical symptoms. Reduced muscle mass and strength despite unchanged activity, increased body fat particularly in the abdomen, reduced bone density (which may manifest as back pain or fracture risk), decreased energy and stamina, hot flushes and sweating, and gynaecomastia (breast tissue enlargement) in severe cases.
Psychological symptoms. Depression, poor concentration, irritability, reduced sense of well-being, and loss of competitive drive. These symptoms are often attributed to stress, burnout, or midlife psychological changes — making TDS one of the most under-recognised causes of mood and cognitive symptoms in middle-aged Indian men.
The validated questionnaire tools
Two questionnaires are widely used in clinical practice to screen for TDS symptoms:
Aging Males' Symptoms (AMS) scale. A 17-item questionnaire covering psychological, somatic, and sexual symptom domains. Scores above 27 are considered symptomatic.
ADAM questionnaire (Androgen Deficiency in Aging Males). A 10-item questionnaire with a sensitivity of approximately 88% and specificity of approximately 60%. A positive screen (yes to questions 1 or 7, or three or more total yes answers) warrants biochemical evaluation.
These questionnaires are screening tools, not diagnostic instruments. A positive screen requires biochemical confirmation.
The diagnostic approach
Step 1: Symptom assessment. Using the AMS scale or ADAM questionnaire, alongside a clinical interview about the symptom spectrum described above.
Step 2: Morning total testosterone. Collected between 7 and 10 AM. If below 12 nmol/L (approximately 350 ng/dL), confirms biochemical deficiency. If 12–15 nmol/L (350–433 ng/dL), is borderline and requires free testosterone measurement. If above 15 nmol/L (approximately 433 ng/dL) with clear symptoms, SHBG and free testosterone measurement are indicated (as described in the free testosterone article).
Step 3: Repeat measurement. If the first result is low or borderline, a second morning sample on a different day confirms the finding before management decisions are made.
Step 4: LH and FSH. To classify the deficiency as primary (testicular failure: low testosterone, high LH) or secondary (pituitary-hypothalamic: low testosterone, low or inappropriately normal LH). Primary hypogonadism requires investigation of testicular causes. Secondary hypogonadism requires pituitary evaluation including prolactin and, in appropriate cases, MRI.
Step 5: Full metabolic assessment. Fasting glucose, HbA1c, fasting insulin, lipid panel, liver function. The metabolic picture informs both the management of TDS and the overall cardiovascular risk profile.
What this evaluation enables
A comprehensive TDS evaluation identifies whether testosterone is deficient, why it is deficient (testicular vs pituitary origin), what metabolic conditions are coexisting and potentially driving the deficiency, and what level of treatment is appropriate and safe. It creates the foundation for a management decision that is individualised — not based on a single number from a midafternoon blood draw.