Oral spironolactone has been proposed as a potential treatment for hair loss due to its antiandrogenic properties. However, the efficacy and safety of spironolactone for treating hair loss are not well-established. The objective of this study was to conduct a systematic review of the current literature on the use of oral spironolactone in female pattern hair loss. We conducted a systematic review and meta-analysis of randomized controlled trials and observational studies that assessed the efficacy and safety of oral spironolactone for treating hair loss. We searched for eligible papers in PubMed, Web of Science (ISI), Embase, and Scopus. All analyses were done using R software version 4.2.3 (R Foundation for Statistical Computing, Vienna, Austria). The overall rate of improved hair loss was 56.60%, with a higher rate of improvement (65.80%) observed in the combined therapy group compared to the monotherapy group (43.21%). However, there was significant heterogeneity in the efficacy outcomes, and hair loss did not improve or showed a modest improvement in 37.80% of all patients. The rates of adverse events reported in at least two studies were scalp pruritus or increased scurf (18.92%), menstrual disorders (11.85%), facial hypertrichosis (6.93%), and drug discontinuation (2.79%). The overall adverse events rate was 3.69%, but there was significant heterogeneity in the rates of different adverse events. In conclusion, the present study suggests that spironolactone is an effective and safe treatment option for hair loss. However, further research is needed to fully understand the heterogeneity of treatment response and adverse events and identify factors that may predict treatment response.