Female pattern hair loss (also called androgenetic alopecia) is a common type of hereditary hair thinning. Women do not become bald like men but their hair becomes quite thin. Female pattern hair loss begins as early as in your 40s and typically continues to develop with continued thinning in your 50s, 60s, 70s & beyond. Hair thinning also starts as early as your teenage years, but it becomes more noticeable once you hit your 20s and 30s. Key features: Less hair on top of you