Topical Prostaglandin Analogues in Androgenetic Alopecia: A Systematic Review of Clinical Evidence

Background: Androgenetic alopecia (AGA) is the most prevalent form of non-scarring hair loss, affecting up to 80% of men before age 70 and 42% of women over their lifetimes. The prostaglandin pathway has emerged as a mechanistically compelling therapeutic target: prostaglandin D2 (PGD2) is markedly elevated in balding scalp and potently inhibits follicular cycling through the GPR44/CRTH2 receptor, while prostaglandin F2alpha (PGF2alpha) and PGE2 promote the anagen growth phase. Objectives: To systematically review published clinical and translational evidence on topical prostaglandin analogues specifically latanoprost, bimatoprost, and the PGD2 pathway modulator cetirizine in the treatment of AGA, evaluating efficacy, safety, and the current limitations of the evidence base. Methods: A systematic search of PubMed/MEDLINE, Embase, and the Cochrane Library was conducted from database inception through January 2026, following PRISMA 2020 guidelines. Of 312 records identified, 65 duplicates were removed, leaving 247 unique records for title/abstract screening; 201 were excluded, yielding 46 full-text articles assessed for eligibility. After applying predefined inclusion and exclusion criteria, 6 primary original clinical studies in human AGA participants were included in the final synthesis, supplemented by foundational translational studies. Results: Six clinical studies met final inclusion criteria. The pivotal RCT by Blume-Peytavi et al. (2012, n=16 men) demonstrated that latanoprost 0.1% significantly increased terminal and vellus hair density at 24 weeks (p