纽约皮肤科医生 Hadley King告诉Insider网站说，是否需要每天洗两次脸取决于你的皮肤类型和你需要洗的东西。
干性或敏感性皮肤可以在晚上清洗一次，但油性皮肤可能需要每天至少清洗两次。然而，如果你锻炼出汗或化了浓妆，她建议在健身后或睡前一定要洗脸。
King说道:“通常建议睡前清洁，不仅是为了卸妆，也是为了去除白天堆积在皮肤上的污垢和污染物。”
她又补充说道，这些颗粒会导致皮肤氧化损伤，胶原蛋白分解并出现皱纹。
“如果你使用的护肤产品过夜后在皮肤上留下残留物或薄膜，那么你可能也会想在早上洗脸。”她对Insider网站说道。
New York City-based dermatologist Hadley King told Insider that whether or not you need to wash your face twice a day depends on your skin type and what you need to wash off.
Dry or sensitive skin types are fine to cleanse once in the evening, but oily skin might require you to cleanse at least twice a day, King said. However, if you complete a sweaty workout or wear heavy makeup, she recommends always washing your face after the gym or before bed.
"Cleansing before bed is generally recommended not only to remove makeup, but also [to remove the] dirt and pollution that accumulates on our skin during the day," King said.
Those particles, she added, can cause oxidative damage and contribute to collagen breakdown and wrinkles.
"If you use overnight skin products that leave a residue or film on your skin, then you will likely want to cleanse your face in the morning as well," she told Insider.
误区3：你的洁面产品只有在使用后脸部感到轻微灼烧或紧绷时才有效。
皮肤科医生、临床护肤品牌DERMAdoctor的创始人Audrey Kunin说道，“没有痛苦就没有收获”不适用于皮肤护理。
她解释道:“当皮肤被护肤成分灼伤或刺激时，会破坏皮肤的保护性酸膜，从而让皮肤变得更敏感，甚至发生感染。”
然而，根据Hu教授的说法，某些酸和处方剂量的类维甲酸会产生轻微的灼烧感或脱皮反应，直到皮肤适应为止。
“一般来说，这些症状会随着活性成分重新平衡细胞新陈代谢而消失。”Hu博士说道。
如果你不确定自己的皮肤对某一产品的反应是否正常，在继续使用之前联系皮肤科医生。
"No pain, no gain" doesn't apply when it comes to skin care, said Audrey Kunin, a dermatologist and founder of the clinical skin-care brand DERMAdoctor.
"When skin is burned or irritated by skin-care ingredients, it upsets the protective acid mantle of the skin, which can lead to further skin sensitivities and even skin infection," she explained.
However, certain acids and prescription-strength retinoids can yield a slight burning sensation or peeling reaction until the skin has adjusted to it, according to Hu.
"In general, these symptoms subside as the cellular turnover gets re-equilibrated by the active ingredient," Hu said.
If you're unsure whether or not your skin's reaction to a product is normal, reach out to a dermatologist before continuing use.
误区4：每天用肥皂和水洗脸就已足够。
“一般的肥皂是用来清洁普通物品的，但你的皮肤可不是普通物品，”纽约皮肤科医生Rachel Nazarian告诉Insider。
她说，传统肥皂会洗去皮肤上的天然油脂，“破坏皮肤的pH值，损伤皮肤屏障”，这会导致皮肤干燥敏感。
相反，用温和的、无香味的洁面乳来清洁面部，它能提供深层清洁，并适配你独特的皮肤情况。
"Regular soap is for cleaning regular things. Your skin is not regular," Rachel Nazarian, a New York City-based dermatologist, told Insider.
Conventional soaps will strip your natural oils and "disrupt the pH of your skin and damage the skin barrier," she said, which can cause dryness and irritation.
Instead, wash your skin with a gentle, fragrance-free cleanser that offers a deep clean and caters to your unique complexion.
误区5：用清洁刷擦洗是进行深层清洁的最好方法。
Hu教授说，与人们普遍认为的相反，用毛巾或机械设备擦洗并不能去除皮肤表面油脂或化妆残留物。
“随着时间的推移，皮肤会对剧烈的机械去角质产生反应，冒出更多油脂，从而导致皮肤堵塞。”她告诉Insider网站说道:“这往往会形成一个恶性循环。”
机械擦洗器甚至会在皮肤上造成“微观裂缝”，从而增加过敏反应或刺激皮肤的风险。
如果你一定要去角质，她建议使用柔软的细布或温和的去角质洁面乳。
Contrary to popular belief, scrubbing with a washcloth or mechanical devices won't scuff away oil or makeup polymers on the surface of the skin, Hu said.
"Over time, your skin responds to aggressive mechanical exfoliation by producing more oil, which can lead to clogging," she told Insider. "This often then becomes a vicious cycle."
Mechanical scrubbers can even cause "microscopic fissures" on the skin that can raise the risk of an allergic reaction or skin irritation.
If you must scrub, she recommends using a soft muslin cloth or a gentle, exfoliating cleanser.
误区6：你长痘痘是因为没有每天都洗脸。
King表示，尽管保持皮肤清洁有助于预防痘痘，但还有其他因素（如基因和荷尔蒙）也会导致长痘。
她说:“如果你是油性皮肤且容易长痘，那么如果不经常洗脸，毛孔就会更加堵塞，痘痘就会冒出来。但如果你不是特别油性的皮肤，也不是特别容易长痘，那即使没有每天洗脸也不太可能会长痘痘。”
Although maintaining a clean complexion definitely helps prevent breakouts, there are other factors — like genetics and hormones — that can cause acne, according to King.
"If you have oily skin and are acne-prone, then yes, you may get more clogged pores and acne breakouts if you are not washing your face regularly," she said. "But if you are not particularly oily or acne-prone, not washing your face every day is not so likely to give you acne."
误区7：别用毛巾擦脸用毛巾擦脸只有在两种情况下才会有问题:第一，如果毛巾被细菌、酵母菌或真菌污染了;第二，如果毛巾磨损太严重，会刺激皮肤。
然而，King说道，如果你是“轻轻拍干而不摩擦”，通常使用干净的毛巾擦脸是没问题的。
Drying your face with a washcloth can only really be problematic in two situations: First, if the cloth is contaminated with bacteria, yeast, or fungi, and second if the cloth is so abrasive it results in irritation.
However, King said it's usually fine to use a clean cloth on your face if you "gently pat dry without rubbing."
误区8：洗脸前不需要卸妆一些人认为洁面乳可以一次性卸妆、清洁皮肤，但Hu强烈建议将卸妆作为护肤的第一步。
她解释说:“化妆品中含有色素、防腐剂、矿物质和金属，如果长时间不卸妆则会堵塞毛孔……还会阻止护肤品的吸收。”“卸妆是夜间生活的第一步，这很重要。”
Some people believe a cleanser can strip away makeup and cleanse the skin one swoop — but Hu highly recommends making makeup removal the first step of your skin-care routine.
"Makeup has pigment, preservatives, minerals, and metals that often can clog your pores if left on too long … and prevent penetration of your skin-care products," she explained. "It is essential to remove makeup as the first step in your nighttime routine."
误区9：只用卸妆湿巾“洗”脸就够了Nazarian 表示，虽然卸妆应该是你夜间日常工作的第一步，但它不应该是唯一的一步，尤其是当你使用卸妆湿巾时。
“清洁湿巾可以去除大量细菌、污垢和油脂，但也会留下一些残留物，”她说。 “这可能会导致粉刺和腺体感染，尤其是在眼睑和睫毛周围。适当的面部清洁需要用水冲洗才能彻底清洁。”
Although removing makeup should be the first step of your nighttime routine, it shouldn't be the only step, especially if you're using makeup-removing wipes, according to Nazarian.
"Cleansing wipes remove a bulk of bacteria, dirt, and oil, but also leave a trail of residue behind," she said. "This can potentially lead to acne and infected glands, especially around the eyelids and eyelashes. Appropriate facial cleansing requires a water-based rinse to fully clean."
误区10：洗脸前不必洗手即使你的手看起来或感觉不脏，也要最好在触摸脸之前先洗手，Hu 说道。
“大多数人经常用手在键盘和手机上打字或开车，”她说，这些表面上的细菌和化学物质会导致皮肤和眼睛刺激或感染，尤其是容易患湿疹的人。
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Even if your hands don't look or feel dirty, it's always best to wash them before touching your face, according to Hu.
"Most people use hands frequently for typing on keyboards and phones, or driving," she said, and the bacteria and chemicals on these surfaces can lead to skin and eye irritation or infection, especially in people who are prone to eczema.
Read More:
- 7 things you think are good for your skin but actually aren't
- Stop putting apple cider vinegar on your face, and 8 other skin care habits dermatologists wish you'd quit
- 10 myths about pores you need to stop believing
- 11 surprising things you didn't realize are damaging your skin
