Thinning hair is common and often treatable. It can affect women and men and can be caused by hormones, genetics, aging, infections, medication, autoimmune diseases, and more. Treatments to stop thinning hair are based on the cause but include supplements, medicated shampoos, prescriptions, and changes to one's hygiene routine. What Causes Thinning Hair? Thinning hair usually results from alopecia (hair loss). If you’ve noticed that your hair looks less full, it may be because you’re losing strands of hair. Sometimes, thinning hair can occur without hair loss. This happens when abnormalities in the hair follicle cause your body to produce strands of hair that are thinner than usual and therefore more prone to breaking. Whether you’re experiencing just hair thinning or hair thinning with hair loss, these causes may be at play:Genetics: Hereditary hair loss (thinning hair or hair loss caused by your genes) is the most common type of hair loss and can occur in people of any sex.Aging: Hai...