“脱发”的秘密，不是头皮中循环不通畅，不是毛囊堵塞，不是营养不良，也不是压力太大。，而是你体内的一种遗传性激素。

Baldness blights the lives of millions of Americans, both men and women, young and old. If you're fighting hair loss, chances are you've heard - and possibly tried - every gimmick out there. When you're this desperate, it's easy to make a mistake that could end up costing you lots of hard-earned cash, or, worse yet, precious hair follicles you don't have to spare.

"As recently as 20 years ago, there was little medical science could do to halt the loss of hair due to hereditary hairloss," says Dr. Alex Khadavi, a board-certified dermatologist and hair-loss expert. "Today, it is possible to find effective natural treatments for hair loss, but first one has to wade through a sea of information and misinformation to find the treatments that work."

Don't fall prey to products that play on these hair-loss myths:

* Poor circulation causes hair loss. -Research shows that medications that increase blood flow to the scalp do not grow hair. As further proof to debunk this myth, Khadavi points out that hair transplanted to balding areas produces new hair growth, demonstrating that there is adequate blood flow to the area to support hair.

*Clogged follicles cause hair loss.- Clogged hair follicles lead to ingrown hair, not hair loss. Shampoos and other products designed to open scalp pores do not stop hair loss or promote regrowth of hair.

*Poor nutrition causes hair loss.- Healthy, well-nourished people still lose their hair and taking nutritional supplements will not regrow hair. There are many supplements for hair loss in the market but even if they have ingredients that have shown to be beneficial for hair loss one would have to take 20-30 pills a day to get enough of those ingredients to the hair follicles to make a difference.

*Stress causes hair loss.- Day-to-day stress does not result in hair loss, no matter how much you fight with your mate or how loudly your boss yells at you. Major stress like surgery or cancer could result in hair loss, but this is usually temporary and the hair will likely regrow without treatment once the stress has passed.

"Dihydrotestosterone (DHT)（二氢睾酮）is one of the main drivers of hair loss,"Khadavi says. Naturally found in males and females, DHT plays a key role in development of male characteristics for both men and women. Some men or women, however, have a genetic propensity for DHT to "attack" hair follicles, especially those on the top of the head. Over time, DHT causes the follicles to become thinner, shorter and weaker, and eventually stops them from regrowing new hair.

（来源：天星教育网 英语点津Jennifer编辑）

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