What is the recommended work‑up and first‑line treatment for androgenetic alopecia in adults, including appropriate laboratory tests and medication options for men and women?

Hair Loss Treatment

For androgenetic alopecia in men, start oral finasteride 1 mg daily combined with topical minoxidil 5% twice daily, as this combination therapy provides optimal results for halting progression and stimulating regrowth. 1

Initial Diagnostic Workup

Clinical Examination

• Examine the scalp for diffuse thinning over the central scalp with preserved frontal hairline in women, or temporal, vertex, and mid-frontal thinning in men—this pattern confirms androgenetic alopecia 1, 2
• Use dermoscopy to identify miniaturized hairs and assess the terminal-to-vellus hair ratio, which provides objective diagnostic data 1
• Rule out other causes: patchy hair loss suggests alopecia areata, scalp inflammation indicates tinea capitis or scarring alopecia 1

Laboratory Testing Strategy

• Most cases require NO laboratory testing when the diagnosis is clinically evident 1
• Check TSH and free T4 only if thyroid disease is suspected, as this commonly causes hair loss 1
• Measure serum ferritin (optimal ≥60 ng/mL needed for hair growth), vitamin D, and zinc only if deficiency is suspected 1
• Order total testosterone, free testosterone, and SHBG only in women with signs of androgen excess (hirsutism, severe acne, irregular periods) 1, 2

Common Pitfall: Avoid ordering extensive autoimmune panels in straightforward cases—this is unnecessary and wastes resources 1

First-Line Treatment for Men

Standard Medical Therapy

• Oral finasteride 1 mg daily is FDA-approved and arrests progression while stimulating regrowth 1, 3
• Topical minoxidil 5% solution twice daily applied directly to the scalp—this is more effective than the 2% formulation 1, 4
• Both medications must be used continuously; stopping treatment results in resumption of hair loss 1, 4

Expected Timeline and Response

• Hair regrowth takes time—results may appear at 2 months but often require 4 months of consistent twice-daily use 4
• Initial increased shedding for up to 2 weeks is expected and indicates old hairs are being replaced by new growth 4
• Not everyone responds equally; men with recent onset and less extensive loss respond better 4

Important Caveat: Dutasteride 0.5 mg (a dual 5-alpha reductase inhibitor) induces better responses than finasteride, especially in the frontal area, though it lacks FDA approval for this indication 3

First-Line Treatment for Women

Medical Therapy

• Topical minoxidil 2% solution twice daily is the FDA-approved first-line treatment for women 1
• Minoxidil 5% is NOT recommended for women as studies show it works no better than 2%, and may cause unwanted facial hair growth 4
• In women with documented androgen excess, add antiandrogens such as spironolactone or cyproterone acetate (always with contraception) 5

Postmenopausal Women

• Postmenopausal women with normoandrogenic alopecia may benefit from finasteride 2.5 mg daily or dutasteride 2.5 mg daily, though this is off-label 5

Adjunctive Treatment Options

Platelet-Rich Plasma (PRP)

• PRP can be added as adjunctive therapy with a protocol of 3-5 sessions at 1-month intervals, then maintenance every 6 months 1
• Clinical trials show increased hair density and hair count per cm² compared to controls 6
• Higher platelet concentrations produce greater effects on hair density and follicle diameter 6
• Microneedling application may be superior to injection technique for anagen promotion and hair length 6

Caveat: Some studies report PRP ineffectiveness, possibly due to low platelet concentration, inadequate volume, or insufficient treatment frequency—individual genetics also play a role 6

Alternative Options

• Low-level laser therapy (LLLT) with wavelengths 630-660 nm used at home for 15-30 minutes daily shows efficacy in limited trials 3, 7
• Oral minoxidil 2.5-5 mg daily is an emerging off-label option with proven effectiveness, though hypertrichosis is the main adverse effect 3
• Topical finasteride 0.25% daily avoids systemic exposure while maintaining efficacy, with less marked decrease in serum DHT 3

Monitoring Treatment Response

Assessment Methods

• Use before-and-after photography for visual comparison at 3-6 month intervals 6
• Trichoscopy with folliscope examination provides detailed assessment of hair miniaturization and vellus hair presence 6
• Hair counts in specific scalp areas and hair diameter measurements provide objective data on treatment response 6
• Patient self-assessment questionnaires capture quality of life improvements 6

When to Reassess

• If no improvement after 4 months of consistent use, stop minoxidil and consider alternative therapies 4
• Regrowth cannot be expected within 3 months of starting any treatment 1

Treatments to Avoid

• Do NOT use potent topical corticosteroids for androgenetic alopecia—there is no evidence of effectiveness 1
• Avoid systemic corticosteroids or PUVA—these have serious side effects without adequate efficacy evidence 1
• Oral zinc and isoprinosine are ineffective in controlled trials 1