Sunscreen Label Guide: Decoding SPF, PA & Beyond

即使在紫外線相對(duì)溫和的冬季，做好防曬依然是日常護(hù)膚重要的一步。面對(duì)產(chǎn)品上各種專業(yè)標(biāo)識(shí)，如何精準(zhǔn)解讀？本文將幫助您化繁為簡(jiǎn)，快速掌握防曬標(biāo)簽的要點(diǎn)。

While UV radiation may be milder in winter, sun protection remains an essential step in daily skincare. With various technical terms on product labels, how can consumers make informed choices? This guide simplifies key sunscreen labeling information for everyday understanding.

「防曬傷關(guān)鍵：SPF值 / UVB Protection: Understanding SPF」

SPF（Sun Protection Factor）是通用的UVB防護(hù)指數(shù)。UVB是導(dǎo)致皮膚曬紅、曬傷的元兇。

SPF (Sun Protection Factor) is the universal metric for UVB protection - the primary cause of sunburn and skin reddening.

1. 定義

SPF值基于“最小紅斑量（MED）"——即導(dǎo)致皮膚剛剛開始出現(xiàn)肉眼可見發(fā)紅（也就是曬紅）所需的最小紫外線劑量。

根據(jù)ISO24444的人體測(cè)試法，SPF=涂防曬霜后的MED ÷ 未涂防曬霜的MED。

簡(jiǎn)單理解，SPF值代表延長(zhǎng)皮膚被曬傷所需時(shí)間的倍數(shù)。

1. Definition

SPF is calculated based on Minimal Erythema Dose (MED) - the minimum UV exposure required to cause just-visible skin reddening. According to ISO24444 human testing protocols:

SPF = MED with sunscreen ÷ MED without sunscreen

Essentially, SPF indicates how much longer protected skin can withstand UV exposure before burning compared to unprotected skin.

2. 防護(hù)效率

SPF值越高，對(duì)UVB的阻擋率越高，但并非線性增長(zhǎng)。

SPF30 ≈ 可阻擋97%的UVB

SPF50 ≈ 可阻擋98%的UVB

值得注意的是，SPF值從30提升到50，阻擋率僅提高了1.3%，但產(chǎn)品質(zhì)地通常會(huì)變得更厚重。

2. Protection Efficiency

Higher SPF values block more UVB, but not proportionally:

• SPF30 ≈ 97% UVB blockage

• SPF50 ≈ 98% UVB blockage

Note: While SPF50 only provides 1.3% more protection than SPF30, the formulation typically becomes heavier.

3. 常見誤區(qū)糾正

• 錯(cuò)誤觀念：SPF值能直接換算成固定的“安全保護(hù)時(shí)長(zhǎng)"。

• 正確觀念：防曬效果會(huì)因使用量、環(huán)境因素等動(dòng)態(tài)變化，所以SPF值代表的是對(duì)紫外線劑量的阻擋能力，而非一個(gè)固定的時(shí)間承諾。如果涂抹量不足，即使使用SPF50的產(chǎn)品，實(shí)際防護(hù)效果也會(huì)大打折扣，可能降至SPF10左右。

3. Common Misconceptions

• Myth: SPF directly converts to guaranteed "safe sun exposure time"

• Fact: SPF indicates UV dose blockage capacity, not fixed time protection. Real-world factors like application amount and environmental conditions significantly impact effectiveness. Insufficient application (less than 2mg/cm2) can reduce SPF50 performance to SPF10 levels.

「防曬黑/防曬老關(guān)鍵：UVA防護(hù) / UVA Protection: Preventing Tanning & Aging」

UVA是導(dǎo)致皮膚曬黑、老化和產(chǎn)生皺紋的主要因素。目前每個(gè)地區(qū)對(duì)UVA的防護(hù)標(biāo)準(zhǔn)尚未統(tǒng)一，主要有以下三種體系：

UVA causes skin darkening, aging and wrinkles. Global UVA protection standards vary:

1. 中日韓標(biāo)準(zhǔn)：PA指數(shù)

PA等級(jí)基于PFA值（防護(hù)UVA指數(shù)），看皮膚要多大的紫外線量才會(huì)開始被曬黑。用“+"號(hào)表示防護(hù)強(qiáng)度：

PA+：PFA 2-3，輕度防護(hù)效果

PA++：PFA 4-7，中度防護(hù)效果

PA+++：PFA 8-15，高度防護(hù)效果

PA++++：PFA≥16，超高度防護(hù)效果

“+"號(hào)越多，越不容易曬黑，防護(hù)UVA的能力越強(qiáng)。

1. Asian Standard: PA Rating

PA grades based on Protection Factor of UVA (PFA) - measuring UV dose required to induce tanning:

• PA+: PFA 2-3 (basic protection)

• PA++: PFA 4-7 (moderate protection)

• PA+++: PFA 8-15 (high protection)

• PA++++: PFA≥16 (very high protection)

More "+" symbols indicate stronger UVA protection. China's highest rating is PA++++.

2. 美國(guó)標(biāo)準(zhǔn)：廣譜防曬（Broad Spectrum）

美國(guó)不采用PA值，而是采用“廣譜防曬"標(biāo)準(zhǔn)。產(chǎn)品必須同時(shí)滿足：

• SPF值≥15

•臨界波長(zhǎng)（CW）≥370納米

達(dá)標(biāo)的產(chǎn)品可標(biāo)注“Broad Spectrum"。未達(dá)標(biāo)的產(chǎn)品則需在標(biāo)簽上注明警示語，提示該產(chǎn)品僅能防曬傷，不能預(yù)防皮膚癌或皮膚老化。

注：臨界波長(zhǎng)（CW）：由美國(guó)皮膚科醫(yī)學(xué)會(huì)提出。指防曬產(chǎn)品經(jīng)過測(cè)試后能阻斷90%紫外線的zui大波長(zhǎng)，簡(jiǎn)單來說，CW數(shù)值越高，能夠防護(hù)的波長(zhǎng)范圍越廣，對(duì)紫外線的防護(hù)效果越好。

2. US Standard: Broad Spectrum

Requirements:

• SPF≥15

• Critical wavelength (CW)≥370nm

Products meeting both criteria can claim "Broad Spectrum." Others must warn they only prevent sunburn, not skin cancer or aging.

Critical wavelength (CW): The longest wavelength blocking 90% of UV. Higher CW values indicate broader UV protection spectrum.

3. 歐洲標(biāo)準(zhǔn)：UVA圓圈與Boots星級(jí)

• UVA圓圈：如果產(chǎn)品包裝上有一個(gè)UVA字母外面畫著圓圈，代表其臨界波長(zhǎng)≥370納米，且UVA防護(hù)力至少達(dá)到SPF值的三分之一。

• Boots星級(jí)：用星級(jí)（一至五星）來標(biāo)示UVA與UVB防護(hù)能力的均衡度。星級(jí)越高，當(dāng)兩者防護(hù)越均衡，越能同時(shí)防護(hù)UVA和UVB，能更全面抵抗紫外對(duì)皮膚的傷害。zui多為五星。

3. European Standard: UVA Circle & Boots Star Rating

• UVA Circle: Indicates CW≥370nm and UVA protection ≥1/3 of SPF value

• Boots Stars (1-5): Rates UVA/UVB protection balance. Higher stars mean more balanced protection against both UV types.

「防水防汗功能 / Water Resistance Claims」

1. 中國(guó)標(biāo)準(zhǔn)

• 抗水抗汗：產(chǎn)品通過40分鐘的測(cè)試，可標(biāo)注“防水防汗"，需注明時(shí)間不超過40分鐘。

• you yue抗水：產(chǎn)品通過80分鐘的測(cè)試，可標(biāo)注“you yue抗水"，需注明時(shí)間不超過80分鐘。

• 若浸泡后SPF值下降超過50%，則不得宣稱具有防水功能。

2. 美國(guó)標(biāo)注

一般標(biāo)注為“Water Resistant"。

1. China Standards

• Water Resistant: Maintains SPF after 40min water immersion

• Very Water Resistant: Maintains SPF after 80min

Products losing >50% SPF after testing cannot claim water resistance.

2. US Standards

Labeled as "Water Resistant "

「其他標(biāo)識(shí) / Additional Label Terms」

• Safe-Eye Tech：產(chǎn)品通過驗(yàn)證測(cè)試，可在眼周使用，不易熏眼。

• Wet Skin：可在濕皮膚上直接涂抹，非常適合海邊、泳池等場(chǎng)景。

• 12M：建議開封后12個(gè)月內(nèi)用完。防曬劑穩(wěn)定性會(huì)隨時(shí)間下降，隔年的防曬霜防護(hù)效果會(huì)大打折扣，不建議繼續(xù)使用。

• Safe-Eye Tech: Ophthalmologist-tested for eye area use

• Wet Skin Application: Can apply to damp skin

• 12M: Use within 12 months after opening for optimal efficacy

說到底，防曬可不是簡(jiǎn)單買個(gè)指數(shù)好的產(chǎn)品就萬事大吉了。真正的秘訣在于“涂夠量、勤補(bǔ)涂"，再搭配上帽子、墨鏡這些硬防曬裝備，才能做到有效的防曬。

記住這個(gè)挑選小竅門：

日常上班通勤：選擇質(zhì)地輕薄、不粘膩的，方便隨時(shí)補(bǔ)涂。

戶外運(yùn)動(dòng)、海邊玩水：防水防汗功能是重中之重，一定要認(rèn)準(zhǔn)明確的抗水標(biāo)識(shí)。

Ultimately, sun protection isn’t as simple as buying the product with the highest SPF and calling it a day. The real secret lies in applying a sufficient amount and reapplying it frequently, combined with physical protection like hats and sunglasses, to ensure complete safety.

Keep this selection tip in mind:

For daily commutes: Choose lightweight, non-sticky formulas for easy reapplication.

For outdoor activities or beach trips: Water and sweat resistance is crucial—always look for clear waterproof labeling.