You need your lips to talk, take duck-face selfies and kiss your loved ones. That's why dry, chapped lips can not only be itchy and painful, they can sometimes be downright embarrassing. But repeatedly applying lip balms and products may not help your case.

与人交谈、嘟嘴自拍、亲吻爱的人，都离不开你的双唇。这也是为什么嘴唇干裂除了发痒和生疼外，有时还会让人陷入特别尴尬的境地。但是，多涂润唇膏或多用润唇产品往往无济于事。

Lip balms provide only temporary comfort, and some types can make scaly¹ lips even drier.

润唇膏只能带来暂时的舒缓。甚至，有些唇膏会让开裂起皮的嘴唇更加干燥。

That's because, in part, when the thin film of moisture from the lip balm evaporates, it dehydrates your lips even more. "It just starts a vicious cycle," Dr Leah Jacob, an assistant professor of dermatology at Tulane University, said.

部分原因是，润唇膏的水薄膜蒸发后，嘴唇脱水会更加严重。“一个恶性循环就这样开始了，”杜兰大学皮肤病学助理教授Leah Jacob博士称。

Many of us have to deal with scaly lips, especially in the cold and dry winter, so doctors and beauty pros² recommend we treat our lips, as well as the rest of our skin.

很多人的嘴唇都会干裂起皮，像鳞片一样，尤其是在干冷的冬天。因此，医生和美容专家都建议我们像护理身体其他部位皮肤一样去护理我们的嘴唇。

"Any part of our body that is not covered in the winter time is going to be subjected to the elements," said Dr Crystal Aguh, an assistant professor of dermatology at Johns Hopkins University. "People tend to get very dry hands in the winter because we're wearing long-sleeved shirts and jackets, but we're not necessarily covering our hands."约翰霍普金斯大学皮肤病学助理教授Crystal Aguh博士称，“在冬天，没有被衣物覆盖的人体部位都会被（干冷的环境）影响。到了冬天，双手往往会变得非常干燥。虽然我们穿着长袖衬衫和夹克，但并没有保护双手。”

Likewise, people rarely cover their faces and lips during the winter time, and so those tend to dry out, too, Aguh said.

同理，在冬天，人们也很少会遮住自己的脸部和嘴唇，因而脸部和唇部往往也会特别干燥，Aguh称。

Although lips look very different from the rest of our skin, they're actually quite similar, Aguh said. Just like the rest of our skin, the lips are made up of three layers of cells: the outermost³ layer of mostly dead cells, known as the stratum⁴ corneum, the epidermis⁵ and the dermis⁶, which sits below it.

Aguh说，尽管唇部看起来与其它部位皮肤完全不同，但实际上构造非常相似。像其它部位的皮肤一样，唇部也是由三层细胞构成：位于表皮最外层的，多数已死亡的细胞（即角质层）、表皮和真皮（位于角质层下方）The main difference is that these layers — especially the stratum corneum, which forms a protective barrier over the others — is much thinner in the lips and, therefore, more vulnerable to damage. Additionally, lips don't have any hair follicles or oil glands⁷ of their own. Instead, the oil from glands around our lips provides moisture.

主要区别在于唇部皮肤的这三层细胞（特别是具有保护其它两层细胞作用的角质层）比其它部位皮肤更薄，故而也更容易受伤。此外，唇部皮肤没有任何毛囊或油脂腺体。唇部保湿需要依靠周围腺体产生的油脂。

Licking your lips or applying a thin gloss⁸, balm or anything out of a tube to supplement that moisture may sound like a good idea, but it can be the worst thing you do for them because it can lead to further dehydration⁹, Jacob said.

Jacob说，舔一舔嘴唇或薄涂一层闪光的唇膏（或其它产品）保湿听起来是一个不错的主意，但实际上这可能是你做的最糟糕的事，因为它会引起进一步脱水。

Some lip balms contain ingredients that can be irritating or drying. Menthol, salicylic acid, cinnamic aldehyde and peppermint¹⁰ flavors are all culprits, Jacob said. "A lot of people don't have any problems with these ingredients, but people with sensitive skin or allergies¹¹ may be more sensitive to these on their lips, as well," she said.

一些润唇膏含有刺激或干燥成分。薄荷醇、水杨酸、肉桂醛和胡椒薄荷香料都是祸因。“很多人都能接受这些成分，不会有任何问题。但敏感肌或者过敏体质者的唇部皮肤可能对这些成分要敏感很多。”

Shiny glosses¹² and oils are also thought to intensify¹³ damage from the sun's ultraviolet (UV) rays, focusing the rays the way a magnifying glass may channel a beam of light onto your lips.

光泽和油会加剧太阳光紫外线的伤害。阳光会被光泽和油聚焦，就像一束光通过放大镜一样照到你的嘴唇上。

But because lips have less melanin — the pigment¹⁴ that gives skin its color — the skin cells in your lips are more likely to sustain sun damage if you use shiny lip products, Jacob said.

但因为唇部的黑色素（赋予皮肤颜色的一种色素）较少，如果你使用闪光的唇部产品，唇部细胞会更容易受到阳光的伤害，Jacob说。

Jacob recommends using a thick, emollient¹⁵ lip balm or ointment¹⁶ with SPF in it to truly protect your lips. Glycerin or plain old petroleum¹⁷ jelly are good ingredients to look for, she noted¹⁸.

Jacob推荐厚涂有SPF防晒指数的镇定润唇（软）膏，以真正保护唇部。她认为甘油或者普通的老凡士林油都是不错的选择。

You can also try using a humidifier at home, which will replenish¹⁹ moisture in the air and, eventually, in your lips. And drink more water to stay hydrated from the inside out.

你也可以在家里装一个加湿器。加湿器可以补充空气中的水分，最终这些水分子也会进入你的唇部。此外，你也可以多喝水，从里到外保持身体的水分。