提問者肯定是看了2019年5月7號全球知名醫學雜誌JAMA發表的一篇初步試驗通訊。裡面報告了幾個防曬成分會經面板吸收進入血液的臨床試驗。

我們再來看看它說的塗抹方法，塗抹面積達到身體面積的百分之75，每天使用四次，按照體表面積X75%X2mg/平方釐米，根據這個來計算，一天的總量分別達到：這4個人每天大概需要使用110克左右的防曬霜，連續使用4天，各位小姐姐們，這個是什麼概念，也就是說每個人4天要用一斤防曬霜。我估計正常人不會這麼喪心病狂的使用防曬霜吧。

我們正常人臉部使用大概是0.7克左右（臉部占身體面板的2%，按照這個面積計算出來）

根據這個量計算，我們面部每天使用一次防曬霜，血液中防曬劑的濃度就會大大的降低。

所以塗防曬霜是利大於弊的，建議大家日常還是選擇硬防曬為主，比如打遮陽傘，戴太陽帽，墨鏡等。如果硬防曬不能滿足的情況下，再塗防曬霜。

防曬霜無論是化學防曬還是物理防曬都是在面板表面起作用，只是方式不同而已，加上面板表面本身有角質層的保護，成分進入血液基本不太可能，首先物理防曬是反射紫外線，不會在面板表面發生反應，相對來說是很安全的，化學防曬是吸收轉化紫外線，防曬效果會比物理防曬強，但很可能會產生自由基，對面板是有一定的損害 。

It took just one day of use for several common sunscreen ingredients to enter the bloodstream at levels high enough to trigger a government safety investigation, according to a pilot study conducted by the Center for Drug Evaluation and Research, an arm of the US Food and Drug Administration.

根據美國食品和藥物管理局下屬的藥品評價和研究中心開展的一項初步研究，防曬霜中的幾種常見成分在塗抹一天後就會進入血液，且濃度高到足以啟動政府安全調查。

The study, published Monday in the medical journal JAMA, also found that the blood concentration of three of the ingredients continued to rise as daily use continued and then remained in the body for at least 24 hours after sunscreen use ended.

5月6日發表在醫學期刊《美國醫學會雜誌》的這項研究發現，三種防曬霜成分在血液中的濃度在日常使用後持續增加，而且在停止使用防曬霜後，這些成分在人體內至少會滯留24個小時。

The four chemicals studied -- avobenzone, oxybenzone, ecamsule and octocrylene -- are part of a dozen that the FDA recently said needed to be researched by manufacturers before they could be considered "generally regarded as safe and effective."

研究中涉及的四種防曬霜成分——阿伏苯宗、氧苯酮、依茨舒、奧克立林是食品和藥物管理局近日要求製造商調查的12種化學成分中的一部分，以確定它們是否“普遍安全有效”。

In the United States, sunscreens were originally approved as an over-the-counter solution to sunburn. They came in two types: one using chemical combos to filter the sun, the other using minerals to block the sun such as titanium dioxide or zinc oxide, which leave a telltale white coating. With many people not wanting to sport a white tint, the popularity of the chemical sunscreens soared.

在美國，防曬霜原本是針對曬傷開出的非處方藥。防曬霜分為兩種：一種是用化合物來過濾Sunny，另一種是用二氧化鈦或氧化鋅等礦物質來阻隔Sunny，礦物質防曬霜會在面板上留下一層白色粉末。因為許多人都不喜歡面板上留下白色痕跡，所以化合物防曬霜變得更加受歡迎。

Because of the way they were used at the time, there wasn"t a lot of concern about a potential health impact. But that soon changed, and the FDA began to ask the industry for safety testing, said David Andrews, senior scientist at the EWG.

環境工作組的資深科學家戴維·安德魯斯說，由於當時防曬霜的使用方式，人們並不擔心防曬霜的潛在健康影響。不過情況很快就發生了改變，因此食品和藥物管理局開始要求防曬霜產業進行安全檢測。

"They were originally used in small quantities to prevent sunburn on vacation," Andrews said. "Now they recommend applying these every day, applying them to large parts of your body. And the FDA began raising concerns."

安德魯斯說：“原本人們只是在度假的時候少量使用防曬霜，以防止被曬傷。但現在商家建議人們每天都使用防曬霜，並在身體上大面積地塗抹。因此食品和藥物管理局開始提醒人們注意。”

The new FDA study enrolled 24 healthy volunteers who were randomly assigned to a spray or lotion sunscreen that contained avobenzone, oxybenzone or octocrylene as ingredients or a crème sunscreen that contained the chemical ecamsule.

食品和藥物管理局的這項新研究招募了24名健康的志願者，隨機讓他們使用含有阿伏苯宗、氧苯酮或奧克立林的防曬噴霧或防曬乳液，或使用含有依茨舒的防曬霜。

The volunteers were asked to put their assigned sunscreen on 75% of their bodies four times each day for four days. Thirty blood samples were taken from each volunteer over seven days.

志願者被要求將指定的防曬霜塗在身體四分之三的面板上，每天塗四次，連續塗四天。在七天時間內，研究人員從每名志願者身上抽取30份血樣。

Of the six people using the ecamsule cream, five had levels of the chemical in their blood considered statistically significant by the end of day one. For the other three chemicals, especially oxybenzone, all of the volunteers showed significant levels after the first day.

使用含有依茨舒的防曬霜的6個人當中，有5個人的血液中所含的化學成分在使用一天後顯著增加。至於其他三種化學成分，尤其是氧苯酮，所有志願者在使用一天後血液中的化學成分顯著增加。

"Looking through the results tables of the study, one thing about oxybenzone stood out," Andrews said. "Oxybenzone was absorbed into the body at about 50 to 100 times higher concentration than any of these other three chemicals they tested."

安德魯斯說：“研究結果顯示，氧苯酮被人體吸收的濃度比測試的其他三種化合物中的任何一種高出50到100倍。”

In 2008, the US Centers for Disease Control and Prevention analyzed urine samples collected by a government study and found oxybenzone in 97% of the samples. Since then, studies have shown a potential link between oxybenzone and lower testosterone levels in adolescent boys, hormone changes in men, and shorter pregnancies and disrupted birth weights in babies.

2008年，美國疾病控制和預防中心分析了一項政府研究中收集的尿樣，並在97%的尿樣中發現了氧苯酮。之後的研究顯示出氧苯酮和青春期男孩的睪酮濃度偏低、男性荷爾蒙變化、孕期縮短和嬰兒出生體重不正常有潛在聯絡。

Of all of the sunscreen ingredients, oxybenzone is known to be the most common cause of contact allergies; a 10-year study found that 70% of people had a positive patch test when exposed.

在所有防曬霜成分中，氧苯酮是接觸性過敏的最常見誘因。長達十年的研究發現，70%的人接觸氧苯酮後在過敏源測試中結果呈陽性。

A Swiss study found oxybenzone or one of four other sunscreen chemicals in 85% of breast milk samples, sparking concern that newborns could be exposed.

瑞士的一項研究發現，85%的母乳樣本中含有氧苯酮或其他四種防曬霜化合物的其中一種，這讓人們擔憂新生兒可能也吸收了這些物質。

And Hawaii, the Pacific nation of Palau and Key West recently banned sunscreens containing oxybenzone and octinoxate because they cause coral bleaching and are dangerous to marine ecosystems.

此外，夏威夷、太平洋島國帛琉和基維斯特最近都禁止使用含有氧苯酮和桂皮酸鹽的防曬霜，因為這些成分導致珊瑚白化，危及海洋生態系統。

So, should you stop using sunscreen? Absolutely not, experts say.

"The sun is the real enemy here," said Scott Faber, senior vice president for government affairs at the Environmental Working Group, or EWG, an advocacy group that publishes a yearly guide on sunscreens.

環境工作組的政府事務高階副Quattroporte斯科特·法伯說：“烈日才是真正的敵人。”環境工作組是一個宣傳組織，每年都會發布關於防曬霜的指南。

"It"s not news that things that you put on your skin are absorbed into the body," Faber said. "This study is the FDA"s way of showing sunscreen manufacturers they need to do the studies to see if chemical absorption poses health risks."

法伯說：“塗在面板上的東西會被人體吸收，這並不是新聞。這項研究是食品和藥物管理局在告訴防曬霜製造商，他們需要透過研究來確定這些被人體吸收的化學物質會不會對健康造成危害。”

"It"s important for consumers to know that for the purpose of this study, sunscreens were applied to 75% of the body, four times per day for four days -- which is twice the amount that would be applied in what the scientific community considers real-world conditions," said Alex Kowcz, chief scientist for The Personal Care Products Council.

個人護理產品委員會的首席科學家艾利克斯·考茨說：“消費者要知道，研究中防曬霜的使用量——塗抹四分之三的身體面積、每天四次、連塗四天——科學界認為這是現實世界中人們使用量的兩倍。”

The council was concerned, she said, that the FDA"s study might confuse consumers and discourage the use of sunscreen.

她說，委員會擔心，食品和藥物管理局的這項研究會讓消費者感到困惑，從而讓人們停止使用防曬霜。

When going outside, the American Academy of Dermatology recommends applying at least 1 ounce of sunscreen to all exposed skin every two hours or after swimming, including "back, neck, face, ears, tops of your feet and legs. If you have thinning hair, either apply sunscreen to your scalp or wear a wide-brimmed hat. To protect your lips, apply a lip balm with a SPF of at least 15," the academy says, adding that since UV rays are always present, sunscreen should be applied to exposed skin even on cloudy days and in the winter.

美國面板科學會建議，外出時每隔兩小時或游泳後要在裸露的面板上塗抹至少1盎司防曬霜，包括“背部、脖頸、面部、耳朵、腳背和雙腿。如果你頭髮稀疏，應在頭皮上塗防曬霜或戴寬簷帽。為了保護嘴唇，應塗抹防曬指數至少15的潤唇膏”。學會還補充說，紫外線無處不在，即使在陰天和冬天也應該在裸露的面板上塗防曬霜。

There are ways to protect yourself and your family other than sunscreen. Seek shade, especially between 10 am and 2 pm. when the sun is at its hottest, and whenever your shadow is shorter than you. Use protective clothing, such as long-sleeved shirts and pants and a hat with a wide brim, and don"t forget the sunglasses.

除了防曬霜以外，還有其他方法可以保護你和你家人的面板。當太陽最毒的時候，尤其是在上午10點到下午2點之間，或影子比你短的時候，要到陰涼處躲避Sunny。穿防護衣，比如長袖襯衫、長褲或寬簷帽，別忘了還有太陽鏡。

"It"s seeking shade, using clothes and when necessary using sunscreen," Andrews said, "but not using sunscreen to prolong your time in the sun."

安德魯斯說：“尋找陰涼處、穿長袖，必要的時候用防曬霜，而不是用防曬霜來延長你在烈日下的時間。”

防曬產品通常分為化學防曬和物理防曬。化學防曬能夠吸收太Sunny，通常含有容易被面板吸收的活性成分如氧苯酮（oxybenzone）、阿伏苯宗（avobenzone）、水楊酸辛酯（octisalate），奧克立林（octocrylene）、甲基水楊醇（homosalate）、肉桂酸辛酯（octinoxate）和依莰舒（ecamsule）等。而物理防曬則是透過反射紫外線來起作用，典型成分是氧化鋅、二氧化鈦，並不會進入血液。