BACKGROUND: Male pattern baldness (MPB) also known as androgenetic alopecia (AA) affects approximately half of men by the fifth decade, and significantly influences both psychological well-being and quality of life. Existing pharmacotherapies include oral finasteride, which reduces dihydrotestosterone (DHT) levels and slows follicular miniaturization, and topical minoxidil, which enhances follicular blood flow and extends the anagen phase. However, adherence to topical regimens can be suboptimal. A combined oral low-dose minoxidil (2.5 mg)-finasteride (1 mg) "All-in-One" regimen could improve convenience, adherence, and possibly efficacy. OBJECTIVE: This retrospective study sought to (i) assess the efficacy of a combined oral minoxidil-finasteride therapy over 12 months in a real-world AA cohort
(ii) determine inter-rater reliability of hair loss scoring metrics
and (iii) examine how baseline Norwood severity influences outcomes and effect sizes. METHODS: Data were collected from a UK-based digital health service between January 2020 and December 2023. Eligible men, aged ≥18, with Norwood stages 2-7 AA, initiated combined oral therapy. All had baseline and 12-month follow-up images. The primary outcome was the mean change in hair density according to a clinician-rated 7-point scale. A one-sample t-test compared the mean change to zero (no change). Cohen's d and Hedge's g estimated effect sizes, and Cohen's kappa assessed inter-rater reliability. RESULTS: Out of 502 men, 92.4% (N = 464) achieved stable or improved outcomes (≥0), and 57.4% (N = 288) showed marked improvements (>
0). The inverse-variance weighted mean 7-point change was 0.58 (95% CI: 0.51-0.65
p<
0.001
N = 502), indicating significant improvement relative to no change. More severe baseline categories achieved equal or greater gains, with effect sizes up to d≈1.0. Kappa values were modest (Norwood: κ=0.33
7-point: κ=0.20), indicating fair to slight agreement. CONCLUSIONS: The combined oral minoxidil-finasteride regimen produced statistically significant and clinically meaningful improvements (p<
0.001
N = 502) in AA over 12 months. The substantial proportion of stable/improved patients (92.4%, N = 464) and large effect sizes in severe stages highlight its potential. However, modest inter-rater reliability underscores the need for refined protocols or potential AI-driven evaluations. Future prospective trials should confirm these findings and explore optimal dosing, patient selection, and long-term durability.