Androgenetic alopecia is a common form of progressive hair loss. This prospective single-arm pre-post interventional study aims to assess tissue Janus Kinase 2 (JAK2) expression in patients with androgenetic alopecia by comparing balding and non-balding scalp at baseline, and to evaluate changes in JAK2 expression in balding scalp after 3 months of topical minoxidil 5% therapy. Clinical response will be assessed using standardized trichoscopic parameters.

This study will recruit 25 adult patients aged 18 to 50 years with mild to moderate androgenetic alopecia attending the Dermatology outpatient clinic, Cairo University Hospital. At baseline, participants will undergo clinical evaluation, standardized photography, and trichoscopic assessment. Three 2 mm scalp punch biopsies will be obtained over the course of the study: one from the balding scalp area and one from the non-balding scalp area at baseline, and one from the balding area after 3 months of therapy. Tissue JAK2 protein levels will be measured by ELISA. Participants will receive topical minoxidil 5% solution for 3 months (1 cc twice daily for men and once daily for women). The primary endpoint is the comparison of tissue JAK2 levels between balding and non-balding scalp at baseline. Secondary analyses will assess change in JAK2 levels after treatment and correlations with clinical improvement by trichoscopy.

Inclusion Criteria:

• Male adults aged 18 to 50 years with androgenetic alopecia.
• Mild to moderate disease severity, defined as Hamilton-Norwood scale II to V.
• Patients who are treatment-naive or willing to undergo an adequate washout period for prior hair loss therapies of at least 1 month.
• Willing and able to provide written informed consent.

Exclusion Criteria:

• Other types of hair loss, including inflammatory or scarring alopecia.
• Inflammatory scalp dermatoses, such as psoriasis or seborrheic dermatitis.
• Use of systemic immunosuppressants, JAK inhibitors, or systemic corticosteroids within the last 12 months.
• History of severe systemic disease, including renal, cardiovascular, or hepatic disease.
• Chemotherapy during the last 5 years.
• Bleeding disorders.

Individual participant data (IPD) will not be shared because this is a single-center study with a small sample size, and de-identification cannot be fully guaranteed. Aggregate results, including summary statistics and outcome analyses, will be made available through publication