Topical minoxidil for androgenetic alopecia

Clinical question

How effective is topical minoxidil for androgenetic alopecia?

Bottom line

In men and women, topical minoxidil improves hair density by about 21 hairs/cm² versus 5 to 9 hairs/cm² (placebo) after 16 to 48 weeks. Oral and topical minoxidil are similarly effective, albeit with different adverse effects. Finasteride is likely more effective than topical minoxidil in men.

Evidence

Results statistically significant unless indicated. One systematic review of randomized controlled trials (RCTs) with extractable data of topical minoxidil, past 5 years.¹

After 16 to 48 weeks:

• Women:

  • -
    Additional hairs/cm² vs placebo: 12 to 14 (2-4 RCTs, N=476-717). Example: 21 additional hairs/cm² minoxidil vs 9 placebo.¹
  • -
    Additional RCT, topical vs oral minoxidil (52 participants²; topical 5% once daily vs 1 mg oral once daily): no difference in additional hairs/cm² or global improvement.
• Men:

  • -
    Additional hairs/cm² vs placebo: 8 to 15 (4-10 RCTs, N=598-1207). Example: 21 additional hairs/cm² minoxidil vs 5 placebo.¹
  • -
    Additional RCT, topical vs oral minoxidil (90 participants³; topical 5% twice daily vs 5 mg oral once daily): no difference in additional hairs/cm². Proportion with improvement at vertex: 46% vs 70% (oral); no difference at frontal areas.
  • -
    Additional RCTs, topical minoxidil vs 1 mg oral finasteride (99 participants⁴; topical 2% twice daily): additional hairs/0.49 cm² (baseline 61-65 hairs): 9.6 vs 18 hairs (finasteride). Improvement: no difference.
    • —
      Topical 5% twice daily (65 participants⁵): improvement: 52% vs 80% (finasteride).
• Examples of adverse effects:

  • -
    Hypertrichosis (25% topical vs 49% oral),³ headaches (2% topical vs 14% oral).³ No meaningful changes in blood pressure or heart rate with oral.^2,3
  • -
    Scalp eczema (16% topical vs 2% oral).³
  • -
    Hair shedding (9-16% oral or topical).³
  • -
    Loss of libido 0% (minoxidil oral or topical) vs 15% (finasteride).⁵

• Limitations: clinical significance of hairs/cm² unclear, few studies looking at patient satisfaction, RCTs often unblinded, mostly in men 30-40 years, high drop-out rates.

Context

• In men, higher efficacy in topical minoxidil with higher concentration: 19 additional hairs/cm² (5%) vs 13 (2%), and patient assessment scores higher (51 on 100-point scale vs 41 for 2%).⁶

  • -Severe scalp symptoms also higher with higher concentration: 4% vs 1%. Inconsistent results in women.⁷

Implementation

Androgenetic alopecia (male or female pattern hair loss) is a multifactorial condition caused by genetic, hormonal, and environmental factors.⁸ It is the most common hair loss type, characterized by progressive thinning of the hair in the frontotemporal and vertex regions in men, and in the frontoparietal region in women.⁸ It can be associated with an impairment in health-related quality of life comparable to, or greater than, acne vulgaris.⁹ Physician-rated severity of alopecia does not correlate with patient experience.⁹ Topical minoxidil (2-5%) is usually the mainstay of therapy, as it is effective and available over the counter.

Tools for Practice articles are adapted from peer-reviewed articles at http://www.toolsforpractice.ca and summarize practice-changing medical evidence for primary care. Coordinated by Dr Adrienne J. Lindblad, articles are developed by the Patients, Experience, Evidence, Research (PEER) team and supported by the College of Family Physicians of Canada and its Alberta, Ontario, and Saskatchewan Chapters. Feedback is welcome at toolsforpractice@cfpc.ca.