Spironolactone typically takes about 8 to 12 weeks (2 to 3 months) to start showing improvements for acne. Full effects might take up to 3 to 6 months of continuous use, depending on the individual and dosage. It works by reducing the production of skin oil linked to hormonal acne, and many women see a significant reduction in acne after this period. Longer-term use is common and considered safe with regular monitoring.