Thinning hair, hair loss, and other hair-related issues can affect people as young as in their teens and early twenties.
人们在青少年和20岁出头时，就有可能遇到头发变少、脱发，以及其他头发相关的问题。
In fact, an estimated 40 percent of men will have noticeable hair loss by age 35, and an estimated 40 percent of women will have visible hair loss by the time they are 40.
数据显示，约40%的男性到35岁时，发量明显减少。40%的女性到40岁时，发量明显减少。
For men, thinning hair usually starts with either a receding hairline or thinning at the crown of the head.
对男性来说，头发变少通常始于发际线后退或头顶变稀疏。
Women begin to notice thinning hair around their part, as it gradually becomes wider.
女性则会先注意到分界线的头发越来越少，分界线越来越宽。
They may also notice that when their hair is pulled back they are able to see more of the scalp than before.
还有，把头发往后梳时，露出的脑门越来越多。
Hair brush
梳子
If there are more strands of hair in your hair brush than normal, it may be a sign of beginning hair loss.
梳子上的发丝如果比正常情况更多，也许是脱发开始的征兆。
Pillow
枕头
A large amount of hair on your pillow when you wake up could be a sign that there is more happening than just normal hair falling out.
起床后枕头上留有大量头发丝，说明比正常掉发更严重的事情正在发生。
Hair loss can be hereditary. Hereditary hair loss is called androgenetic alopecia, or for males, male pattern baldness, and for females, female pattern baldness.
脱发有可能是遗传性的。遗传性脱发又称为雄激素源性脱发，分为男性雄性脱和女性雄性脱。
Androgenetic alopecia occurs when a hair follicle sheds, and the hair that replaces it is thinner and finer than what was there previously. The hair follicles continue to shrink and eventually hair stops growing altogether.
遗传性脱发的过程是毛囊脱落，新长出的头发比之前更细软，毛囊逐渐萎缩，最终头发停止生长。
It can be passed down from either the mother's or father's genes – but is more likely to occur if both parents have this issue.
父母的脱发基因都可能遗传给下一代，如果父母双方都脱发，下一代脱发的可能性更高。
Poor nutrition and low iron levels.

营养不良、缺铁。
Women with heavy menses or who are anemic can experience hair loss.
经血多或贫血的妹子可能掉头发比较多。
Wearing hair in tightly braided styles.
扎头发过紧。
Starting or stopping birth control pills.
使用或停止使用避孕药。
For some women BCP help slow hair loss, for others, they make it worse.
有些女生吃避孕药会减缓脱发，有些则会加剧脱发。
Cosmetic procedures such as bleaching or perming hair.
烫染等美发手段
Recent child birth
刚生完孩子
Certain medications
某些药物
Thyroid problems, diabetes, other illnesses
甲状腺、糖尿病等疾病
Stress
压力
Thinning hair and hair loss in younger men is usually a result of androgenetic alopecia, but it can also be brought on by poor nutrition and stress.
年轻男性发量减少和脱发通常是雄激素源性脱发，但也有可能是营养不良和压力造成的。
Keep cool: In general, the less heat you use, the better. Styling with heat can damage the hair, and if you must use heated tools, pick those with adjustable settings and keep them on the lowest level.
让头发凉爽点：给头发带去的热量越少越好。用热风做造型很损害发质。如果一定要用加热工具，用可调节温度的并把温度调至最低档。
Brush with care: Used in conjunction with a blow-dryer, round metal brushes can heat up significantly, and some brushes with hard plastic or metal bristles can cause breakage. Instead, try a brush made of gentle boar bristles or flexible nylon.
温柔点梳头：圆形金属梳子配合吹风机使用时，会急剧变热。硬塑料梳和钢丝鬃刷会损害头发。换一把猪鬃毛或者尼龙做的小梳子吧。
Get a volumizing cut: In most cases, shorter cuts are kinder to thinning hair. Whatever length you choose, ask for interior layers, which are placed throughout your cut, not just on the ends, to add fullness.
剪一头精干的短发：多数情况下，短头发对发量变少的人来说更友好。无论头发剪到什么长度，都要让理发师给打层次，不仅发尾，整个发型都需要，这样能制造发量充盈感。
Switch your part: Hair tends to lie flatter against the scalp when brushed repeatedly in the same direction; if you typically part your hair on the left, flip it to the right, so it's more likely to stand away from your scalp and look more voluminous.
换个分缝方向：如果你总是把头发往同一个方向梳，头发就会趴在头皮上。所以如果你习惯往左边分缝的话，就把头发甩到右边去，这样你的头发就更容易从头皮上“站”起来，看起来更浓密。
Over-shampooing causes hair loss.
频繁洗头会导致脱发。
Many people tend to think that over-shampooing can cause hair loss because a lot of the time our hair falls out naturally in the shower, and it may seem like more hair falling out than normal.
很多人以为频繁洗头会引起脱发，其实洗头时头发是自然脱落的，只是掉的头发看上去比平时要多一些。
Gel, hairspray and shampoo do not cause balding. But some men tease their hair and use curling irons, which could speed up the process.
发胶、定型喷雾、洗发水都不会引起脱发。但是反梳头发、用烫发钳有可能加速脱发。
Wearing a hat strains hair follicles, causing hair to fall out.
戴帽子会对毛囊产生压力，从而引起脱发。
Good news for men who rely on caps to cover their shiny crowns: They're not causing any harm. Dirty hats can, however, lead to a scalp infection, which in turn accelerates hair loss, so either make sure yours is clean or rotate frequently.
用帽子遮谢顶的男士们有好消息了：帽子并不会对头发造成伤害，但脏帽子会！脏帽子有可能引发头皮感染，进而加速脱发。所以，要么把帽子洗洗干净，要么经常换着戴。

Loading up on carbohydrates can lead to hair loss.
吃太多碳水化合物会导致脱发。
Carbohydrates and red meat provide nutrients that are helpful for maintaining a full head of hair, says Wilma Bergfeld, a dermatologist at the Cleveland Clinic. Bergfeld's past research suggests that iron deficiency may be closely linked to hair loss. Treatment — like taking iron supplements—could restore growth.
克利夫兰诊所的皮肤科医生威尔玛·贝格菲尔德表示，碳水化合物和红肉能提供营养，帮你保住浓密的头发。贝格菲尔德过去的研究还显示，缺铁跟脱发密切相关，补铁可以帮助头发恢复生长。
The most sexually active men are the first to go bald.
性生活丰富的男性最容易秃顶。
This is one of the most popular myths. Relax — there's no truth to it. Research has also found that men who bald do not have more testosterone than their hairier friends.
这是最常见的误区之一。放心吧，没有这回事。研究还显示，秃顶的男士体内的睾丸素并没有比毛发茂密的朋友更多。