Is finasteride (oral medication) the same as minoxidil (topical solution)?

No, Finasteride and Minoxidil Are Completely Different Medications

Finasteride and minoxidil are two distinct medications with entirely different mechanisms of action, formulations, and side effect profiles used to treat androgenetic alopecia (AGA). 1

Key Differences

Finasteride

• Mechanism: Finasteride is a synthetic 4-azasteroid compound that specifically inhibits Type II 5α-reductase, an intracellular enzyme that converts testosterone into dihydrotestosterone (DHT), reducing DHT levels by approximately 70% in serum and 80% in prostate tissue. 2
• Formulation: Primarily available as an oral medication (1 mg daily for hair loss, 5 mg for benign prostatic hyperplasia), though topical formulations exist off-label. 1, 2
• FDA Status: FDA-approved for male pattern hair loss (oral formulation only). 3
• Onset: Slow onset of action compared to other treatments, requiring months to see improvement. 1

Minoxidil

• Mechanism: Acts through multiple pathways including vasodilation, anti-inflammatory effects, Wnt/β-catenin signaling induction, and antiandrogen properties to promote hair growth. 4
• Formulation: Primarily topical solution (2% or 5%), though oral formulations are used off-label. 1
• FDA Status: FDA-approved as topical treatment for both male and female pattern hair loss. 5
• Onset: Generally faster visible results than finasteride. 3

Clinical Efficacy Comparison

In head-to-head trials, oral finasteride demonstrates superior efficacy to topical minoxidil for male AGA. 3

• A randomized comparative study showed clinical cure rates (increased hair intensity) of 80% with oral finasteride 1 mg/day versus 52% with 5% topical minoxidil after 12 months of treatment. 3
• Both medications are effective and safe, but finasteride showed statistically superior results in this direct comparison. 3

Side Effect Profiles

Finasteride Side Effects

• Sexual dysfunction: Decreased libido, ejaculatory dysfunction, and erectile dysfunction (reversible upon discontinuation). 1, 3
• Hormonal changes: Decreases serum DHT and prostate-specific antigen (PSA) by approximately 50%; increases total testosterone. 1, 3
• Post-finasteride syndrome: Controversial constellation of persistent sexual, physical, and psychological symptoms after discontinuation, though data supporting this remains largely anecdotal. 1
• Other: Gynecomastia (more common with finasteride than dutasteride's alternative eplerenone in other contexts). 1

Minoxidil Side Effects

• Topical: Scalp irritation, pruritus, burning sensation, contact dermatitis, and erythema localized to application site. 6, 7
• Oral (off-label): Hypertrichosis (unwanted body hair growth) and cardiovascular symptoms in dose-dependent manner. 4
• Local effects: Itching, shedding, and dandruff are common. 7

Combination Therapy

Combining topical finasteride with minoxidil may enhance efficacy for androgenetic alopecia. 1, 6

• The combination of topical minoxidil and topical finasteride shows promise for improved outcomes compared to monotherapy. 6
• A 12-week randomized trial found that topical finasteride 0.1% combined with minoxidil 5% had similar safety and effectiveness to minoxidil 5% alone, with significant increases in hair density, diameter, and terminal hair rate in both groups. 7
• Topical finasteride reduces both scalp and plasma DHT levels while minimizing systemic side effects compared to oral formulation. 6

Important Clinical Considerations

• Finasteride is ineffective in patients without prostatic enlargement when used for benign prostatic hyperplasia, which may have implications for patient selection in AGA treatment. 1, 8
• PSA monitoring: Men on finasteride require adjusted PSA interpretation—after 1 year of therapy, measured PSA values should be doubled to accurately gauge prostate cancer risk. 1
• Pregnancy contraindication: Finasteride is contraindicated in pregnancy due to teratogenic effects. 2
• Treatment duration: Both medications require continuous use to maintain benefits; discontinuation leads to reversal of hair growth improvements. 1