What is the recommended evaluation and work‑up for an adult patient presenting with decreased libido?

Work-Up for Decreased Libido

Measure morning total testosterone (8–10 AM) in every adult presenting with decreased libido, obtain a comprehensive sexual and psychosocial history, and perform targeted laboratory screening for metabolic and cardiovascular risk factors. 1, 2

History Taking

A detailed sexual history is the cornerstone of evaluation and must systematically explore the onset (sudden vs. gradual), duration, severity, and context of decreased libido. 1

• Assess whether the problem is generalized (affecting all situations) or situational (partner-specific, performance-related, or context-dependent), as this distinction helps differentiate psychogenic from organic causes 3, 1
• Inquire specifically about the presence of morning or nocturnal erections and masturbatory erections—preservation of these indicates intact neurovascular function and points toward a psychogenic component 1, 2
• Screen systematically for depression, anxiety, relationship conflict, recent major life stressors, and trauma history, as these psychological factors commonly precipitate sexual dysfunction 1, 2
• Document all current medications, with particular attention to antidepressants (SSRIs, tricyclics), antihypertensives (beta-blockers, thiazide diuretics), antipsychotics, antiandrogens (GnRH analogues, 5α-reductase inhibitors), and recreational drugs (heroin, cocaine, marijuana, anabolic steroids, excessive alcohol), as these are common iatrogenic causes 3
• Evaluate partner-related factors including partner's sexual function, vaginal dryness in female partners, erectile dysfunction in male partners, and overall relationship satisfaction 1
• Assess for chronic medical conditions that impact libido: diabetes, hypertension, cardiovascular disease, chronic kidney disease, liver disease, obstructive sleep apnea, inflammatory bowel disease, chronic fatigue syndrome, and cancer treatment history 3

Physical Examination

Perform a focused examination evaluating body habitus, BMI, signs of hypogonadism, cardiovascular risk, and genital abnormalities. 3, 1

• Assess virilization status including body hair distribution, gynecomastia, and testicular size/consistency to identify hypogonadism 3, 1
• Measure blood pressure and evaluate peripheral pulses (carotid, femoral, pedal) to assess cardiovascular risk 1
• Examine the genitalia for penile deformities (Peyronie's disease, congenital curvature), testicular atrophy, and prostate abnormalities 3
• Document BMI, as obesity is a major confounder of testosterone levels and independently contributes to sexual dysfunction 3

Laboratory Testing

Morning total testosterone measurement is mandatory in all patients with decreased libido, with repeat testing if abnormal. 3, 1, 2

Hormonal Studies

• Obtain morning (8–10 AM) serum total testosterone on two separate occasions if the initial value is low (<300 ng/dL), as this confirms hypogonadism 1, 2
• Measure free testosterone or calculate the androgen index (using total testosterone, sex hormone-binding globulin, and albumin) when total testosterone is borderline, as this prevents unnecessary endocrine investigation in up to 50% of men with low total testosterone 1
• If testosterone is confirmed low, measure luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin to distinguish primary from secondary hypogonadism 3, 1, 2
• Prolactin measurement is indicated only when testosterone is low; routine prolactin screening is not recommended otherwise 2

Metabolic and Cardiovascular Screening

• Obtain fasting glucose or HbA1c to screen for diabetes mellitus, as diabetes is strongly associated with decreased libido and erectile dysfunction 3, 1, 2
• Measure a fasting lipid panel (total cholesterol, LDL, HDL, triglycerides) to evaluate dyslipidemia and cardiovascular risk 1, 2
• Consider complete blood count, electrolytes, and liver function tests as part of baseline metabolic assessment, particularly if testosterone replacement is being considered 2

Additional Testing When Testosterone Replacement Is Planned

• Measure baseline hemoglobin and hematocrit before initiating testosterone therapy; withhold therapy if hematocrit exceeds 50% 2
• Obtain prostate-specific antigen (PSA) in men over 40 years before starting testosterone; two consecutively elevated PSA results mandate urologic evaluation prior to hormone therapy 2

Validated Screening Questionnaires

Use structured instruments to quantify severity and facilitate discussion, but do not rely on questionnaires alone to replace full clinical evaluation. 1

• Consider the International Index of Erectile Function (IIEF) or Sexual Health Inventory for Men (SHIM) for men to assess erectile function alongside libido 3, 1
• For women, options include the Female Sexual Function Index (FSFI), Brief Sexual Symptom Checklist for Women, or the Arizona Sexual Experiences Scale (ASEX) 3
• Recognize that these tools have variable specificity and sensitivity and should not substitute for laboratory testing and comprehensive history 1

Cardiovascular Risk Assessment

Decreased libido, particularly when accompanied by erectile dysfunction, serves as a marker for underlying cardiovascular disease and warrants formal risk stratification. 3, 2

• Use the American College of Cardiology/American Heart Association atherosclerotic CVD risk assessment based on pooled cohort equations, categorizing patients as low (<5%), borderline (5–7.5%), intermediate (7.5–20%), or high (>20%) risk 3
• For borderline/intermediate-risk patients aged 40–60 years, consider coronary artery calcium scoring 3
• Communicate cardiovascular risk findings to the patient's primary care provider, as erectile dysfunction predicts future cardiac events with a magnitude comparable to smoking or family history of myocardial infarction 2

Common Pitfalls to Avoid

• Do not delay testosterone testing when loss of libido is reported—the combination of decreased libido with sexual dysfunction makes testosterone deficiency highly likely and treatable 2
• Do not assume that preserved morning erections mean "it's all in the head"—psychogenic erectile dysfunction still benefits from PDE5 inhibitors initiated concurrently with psychological therapy 2
• Do not treat decreased libido without addressing cardiovascular risk—men with organic sexual dysfunction should be considered at increased cardiovascular disease risk until proven otherwise 2
• Do not overlook medication-induced causes—antidepressants, antihypertensives, and antipsychotics are common culprits that must be reviewed and potentially adjusted 3
• Do not ignore the partner—involving the sexual partner in assessment and treatment improves adherence and outcomes 3, 2