About half of all women find their hair thinning by age 50. Although some websites promote estrogen as a way to prevent hair loss, the hormone’s effects on hair growth are not well known, and long-term
hormone therapy is linked to serious health risks, “so unless you need to take it for other reasons, it’s not something I would recommend,” said Dr. Paradi Mirmirani, the regional director
for hair disorders at Kaiser Permanente-Northern California.
The “gold standard” medical treatment for hair thinning is a drug applied to the scalp called minoxidil, widely known by the brand name Rogaine. The Food and Drug Administration has approved minoxidil
for women as well as men, and you don’t need a doctor’s prescription to buy it.
The directions say patients will see an improvement in hair growth in six weeks, but Dr. Mirmirani suggested trying it for six months before deciding whether it works or not. About a third of patients who use
it see significant improvements, another third find it prevents hair loss from getting worse, and the remainder don’t see any effect, she said.
“It’s like fertilizer for the hair — it’s not going to give you new blooms where you don’t have any, but it can potentially increase the size of the blooms, and make them last
a little longer,” she said. Some women experience unwelcome side effects such as increased facial hair.
Other approaches to hair thinning include using cosmetic “camouflage” sprays and powders that cover the scalp with a color close to one’s
own hair color, which reduces the contrast between hair and scalp and makes the hair loss less noticeable. Surgical hair transplants are an option, but you must have enough “donor” hair to spare
at the back of your scalp. A new treatment approved by the F.D.A. uses low-level laser lights on the scalp but the benefit is “modest,” Dr. Mirmirani said.
A sudden, dramatic loss of hair can be triggered by major surgery or certain medical conditions, including thyroid problems or iron-deficiency anemia. Crash diets and some prescription drugs, including antidepressants,
blood thinners, antibiotics and birth control pills, among others, can also cause a lot of shedding.