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1. Androgenetic alopecia (AGA) is the most common cause of hair loss in adults,
affecting up to 80% of men and 50% of women throughout their lives. This article is dedicated to androgenic alopecia (pattern baldness). However, there are many other causes of hair loss that will be covered in future articles, including hypothyroidism, stress, medications, oncologic treatments, vitamin B12 deficiency, bariatric surgery, seborrheic dermatitis, and others.

2. Causes and pathophysiology
Genes + androgens (DHT): In men, DHT acts closely on the follicles. In women, the
cause is still not entirely clear, but it is associated with follicular sensitivity and, in some cases, hyperandrogenism.
Follicle miniaturization: The follicle produces finer hairs with each cycle until it
stops growing.

3. Types of Baldness
Type: Male (Norwood scale) Female (Ludwig scale) Characteristics
Male Norwood pattern I–VII — Receding forehead + loss of crown
Female Ludwig pattern I–III — Diffuse thinning at the vertex, sparing the hairline

4. Available Treatments
4.1. Therapies with the most evidence
Treatment Gender % Success (improves density or stops hair loss) Side effects
**Topical minoxidil 5%** Both ~40% of men show revitalization in 3-6 months Mild irritation, facial hirsutism
Oral finasteride 1 mg Men only ~80% improvement in density vs. 52% with
minoxidil 5% � libido (2-7%), erectile dysfunction
Oral dutasteride (off-label) Men only More effective than finasteride Similar to
finasteride
Topical finasteride Both Reduces hair loss and increases follicle count Lower risk
of systemic effects
Combinations (minox + finasteride) Both 84% success rate maintaining density
after 1 year Mild combined effects
Low-level laser, microneedling, PRP Both Significant increase in hair count and
thickness Injection: mild pain, inflammation
Botox Intradermal Men Significant improvement after 24 weeks Mild discomfort,
mild temporary paralysis

4.2. Emerging Therapies
Stem cells + ATP: in mice, regenerates 100% hair in males and 90% in females. Humans still in the experimental phase.

5. Efficacy Comparison
In men, oral finasteride is superior to topical minoxidil (80% vs. 52% success). Combinations (minox + finasteride) offer superior results (~84% success).
Adjuvant therapies (laser, microneedling, PRP) provide density improvements of 15-30% over monotherapy.

6. Prognosis
Short-term (3-6 months): Most patients stop hair loss; 30-50% see new hair growth
with minoxidil or finasteride.
Long-term (>12 months): Density continues to improve with sustained use; if
treatment is discontinued, hair gains are lost within a few months.

7. Recommendations by type
Norwood II–V men: Start with oral finasteride + 5% minoxidil. Add PRP or laser if
partial response is achieved.
Ludwig I–III women: Use 2% or 5% minoxidil (foam with less irritation); consider
topical finasteride, PRP, and laser. Oral finasteride is not approved except for postmenopausal women under supervision.
Emerging therapies: microneedling, local Botox, and potential future stem cell
therapy + ATP.

8. Expected results
5% minoxidil: 40% hair recovery in men, similar in women; improvement evident in 4–6 months.
Oral finasteride: 80% positive effects at 6 months.
Combination: Up to 84% maintain density after 12 months.
Adjuvant therapies: microneedling + minoxidil achieve 83% satisfaction in small
studies.

9. Conclusion
Androgenetic alopecia is chronic, but manageable:
Combination therapy is the most effective.
It is crucial to continue treatment indefinitely to maintain results.
Side effects are generally mild and reversible.
New biotechnological therapies have great potential, but are not yet available for humans.

Raul Ayala, MD
@MyDoctorOnCall.com