Some treatments in development hold particular promise for women. Angela Christiano, a hair geneticist and Columbia University professor of dermatology, is hoping to begin clinical trials in a year or two on a procedure in which she dissects hair-follicle stem cells, grows them in the lab until she has several million, then injects them into the scalp, where, a very small study done with a human skin model has shown, they induce new hairs.
1. Minoxidil. It’s the only FDA-approved topical nonprescription medication that can claim to regrow hair — and it should be part of any hair-loss plan if you have serious thinning, says Rogers. Minoxidil has loads of research to back it, but it requires commitment. If you quit using it, your hair will start to lose ground again. Use a 5 percent strength, like Women’s Rogaine 5% Minoxidil Foam ($30), once daily to see results in three to four months, says Rogers.
In either sex, hair loss from androgenetic alopecia occurs because of a genetically determined shortening of anagen, a hair's growing phase, and a lengthening of the time between the shedding of a hair and the start of a new anagen phase. (See "Life cycle of a hair.") That means it takes longer for hair to start growing back after it is shed in the course of the normal growth cycle. The hair follicle itself also changes, shrinking and producing a shorter, thinner hair shaft — a process called "follicular miniaturization." As a result, thicker, pigmented, longer-lived "terminal" hairs are replaced by shorter, thinner, non-pigmented hairs called "vellus."