當我們選購防曬霜或帶有防曬功能的化妝品時，包裝上的“SPF 50+"、“PA++++"等標識，并非隨意標注，而是基于科學測試標準所得出的結果。

多年來，行業普遍遵循ISO 24444標準，通過模擬日光照射，觀察人體皮膚產生曬傷紅斑的程度來測定防曬指數。這一方法雖然經典，但其依賴人體產生可見曬傷的測試過程，在效率、倫理和消費者日益關注的安全性與透明度上，正面臨挑戰。

ISO 23698作為一項新發布的國際標準，為防曬功效測評提供了另一種技術方案。這項標準引入的混合漫反射光譜法，在測試方法學上進行了重要更新，提升了測試過程的效率和安全性。了解從ISO 24444到ISO 23698的技術演進，不僅關乎行業的技術升級，也與每一位消費者未來所購買產品的可信度與安全息息相關。

「從生物學反應到光學測量的演進」

傳統方法如ISO 24444依賴人體皮膚的紅斑反應（曬傷）來測定防曬指數（SPF）。ISO 23698標準的發布則引入了一種混合測量方法，其核心創新在于采用混合漫反射光譜法（HDRS），大幅減少了測試過程對人體皮膚的傷害。

傳統SPF測試的挑戰：

ISO 24444的測試流程涵蓋受試者篩選、個體最小紅斑劑量（MED）測定、樣品涂抹、紫外線照射及紅斑評估等多個環節。關鍵步驟包括：

• 受試者篩選：需招募18-65歲健康成人，皮膚光型以I-III型為主，排除有皮膚病史或光敏性藥物使用史者。

• 劑量控制：樣品標準涂抹量為2.0mg/cm2，均勻涂抹后靜置15分鐘成膜。

• 紅斑判讀：光照后20-24小時內，由訓練有素的評估員盲法判讀剛可見紅斑（MED）的臨界點。

盡管該流程確保了結果的可比性，但其依賴人體曬傷反應的本質限制了其應用效率和倫理接受度。

HDRS方法的突破性優勢：

新標準同樣需要在人體皮膚上進行測試，但其優勢在于不再需要以皮膚曬傷作為測量終點。它通過結合體外光譜測量與體內皮膚漫反射光譜（DRS）測量，實現了對SPF、UVA-PF和臨界波長（CW）的同步測定。這種方法避免了測試過程中對皮膚造成紅斑損傷，提升了測試的安全性與倫理接受度。

人體曬傷反應

「測試流程全景」

新標準根據紫外線波段特性，采用不同方法分別測量UVA和UVB的防護效果。

• 儀器準備

設備校準與驗證

• 受試者篩選與UVA波段體內測量

測試在健康志愿者的背部進行。標準會篩選皮膚類型、顏色合適且近期無紫外線暴露史的受試者。

UVA測量是HDRS技術在人體皮膚上直接進行的部分。光學探頭通過測量320-400nm波長的UVA光線在涂有防曬產品的皮膚上的反射情況，直接計算出產品對UVA的防護能力（UVA-PF）。此過程僅需光學掃描，無需紫外線照射皮膚，故無傷害。

• UVB波段體外測量與數據融合

UVB部分的測量在體外完成。在特制的塑料板上涂抹防曬產品，用儀器精確測量其阻擋UVB的光譜數據。

將體外測得的全波段數據與人體皮膚上測得的UVA數據進行整合，生成完整的紫外線吸收光譜。

• 數據計算與驗證

計算機利用特定的計算公式，將融合后的光譜數據轉換為具體的SPF、UVA-PF等數值。整個過程通過標準品的比對和統計規則進行驗證，確保數據達到預設的精度要求。

「技術邊界與行業影響」

ISO 23698的推出不僅是測試方法的升級，更推動了防曬產品研發向更高效率、更精確、更人道的方向發展。其技術優勢包括：

• 安全性顯著提升：通過光學測量替代紅斑反應，杜絕了測試過程中對志愿者皮膚造成曬傷的風險，體現了更強的倫理關懷。

• 數據維度豐富高效：同步輸出SPF、UVA-PF和CW，一次測試即可全面評估防曬效能，大大縮短了研發周期。

• 客觀性與可追溯性強化：減少人為判讀紅斑的主觀誤差，并通過標準品校準和光學設備監控，提升實驗室間結果的可比性。

這項技術的普及，將使防曬產品的功效數據建立在更科學、更安全、更可信的基礎上，標志著防曬測評進入一個以光學技術為核心的新發展階段

「產品推薦」

Solar Light 開發的 HDRS 測試系統——Poly602 與 Mono602 型號，符合 ISO 23698 測試標準，為防曬產品測評提供高效、可靠的技術解決方案。

產品優勢

• 快速獲取SPF和UVA-PF結果

• 單次測量僅需3-4秒（Poly602）/ 30秒（Mono602系統）

• 無皮膚紅斑反應，照射總能量低于國際紫外線安全閾值

• 受試者每7天可參與一次混合漫反射光譜（HDRS）測試

系統核心配置

• Poly602 / Mono602 HDRS主機

• LS1000太陽光模擬器

• SPF290紫外線透過率分析儀

• PMMA測試板

• RestAssured 服務、維護與保修

愛博能作為其在中國區的代理商，為您提供符合防曬測試標準的測試系統及全套解決方案。歡迎垂詢了解更多！

ISO 23698 Sun Protection Testing Standard: How It Affects Your Sunscreen Choice

When purchasing sunscreen or cosmetics with sun protection, labels such as "SPF 50+" and "PA++++" on the packaging are not arbitrary; they are derived from scientific testing standards.

For years, the industry has widely followed the ISO 24444 standard, which measures the sun protection factor by simulating sunlight exposure and observing the degree of erythema (sunburn) on human skin. Although this method is classic, its reliance on inducing visible sunburn in human subjects presents challenges in terms of efficiency, ethics, and the growing consumer demand for safety and transparency.

As a newly published international standard, ISO 23698 offers an alternative technical approach for evaluating sun protection efficacy. This standard introduces Hybrid Diffuse Reflectance Spectroscopy (HDRS), representing a significant methodological update that improves the efficiency and safety of the testing process. Understanding the technical evolution from ISO 24444 to ISO 23698 is relevant not only for industry technological advancement but also for the credibility and safety of the products every consumer will purchase in the future.

Evolution from Biological Response to Optical Measurement

Traditional methods like ISO 24444 rely entirely on the erythemal response (sunburn) of human skin to determine the Sun Protection Factor (SPF). The introduction of the ISO 23698 standard brings in a hybrid measurement method. Its core innovation lies in adopting Hybrid Diffuse Reflectance Spectroscopy (HDRS), significantly reducing harm to human skin during testing.

Challenges of Traditional SPF Testing

The ISO 24444 testing protocol involves multiple steps: subject screening, determination of individual Minimal Erythema Dose (MED), product application, UV irradiation, and erythema assessment. Key steps include:

• Subject Screening: Requires recruiting healthy adults aged 18-65, primarily with skin phototypes I-III, excluding individuals with a history of skin disease or use of photosensitizing medication.

• Dosage Control: The standard product application amount is 2.0 mg/cm2, applied evenly followed by a 15-minute waiting period for film formation.

• Erythema Reading: 20-24 hours after irradiation, trained assessors perform blind readings to determine the endpoint for the just-perceptible erythema (MED).

While this process ensures result comparability, its inherent reliance on inducing sunburn in humans limits its application efficiency and ethical acceptance.

Breakthrough Advantages of the HDRS Method

The new standard also requires testing on human skin, but its advantage is that it no longer requires skin sunburn as the measurement endpoint. By combining in vitro spectroscopic measurements with in vivo skin Diffuse Reflectance Spectroscopy (DRS) measurements, it enables the simultaneous determination of SPF, UVA-PF, and Critical Wavelength (CW). This method avoids causing erythema damage to the skin during testing, enhancing safety and ethical acceptance.

MED

Panorama of the Testing Process

Based on the characteristics of UV wavelength bands, the new standard employs different methods to measure UVA and UVB protection effects separately.

a. Instrument Preparation

Calibration and Verification

b. Subject Screening and In Vivo UVA Band Measurement

Testing is conducted on the backs of healthy volunteers. The standard screens for suitable subjects based on skin type and color, and who have had no recent UV exposure.

The UVA measurement is the part where HDRS technology is directly applied to human skin. An optical probe measures the reflection of UVA light (320-400nm) from skin treated with the sunscreen product, directly calculating the product's UVA protection ability (UVA-PF). This process involves only optical scanning without exposing the skin to UV radiation, thus causing no harm.

c. In Vitro UVB Band Measurement and Data Fusion

The UVB portion is measured entirely in vitro. The sunscreen product is applied to specialized plastic boards, and instruments precisely measure its spectral data for blocking UVB.

The full-spectrum data obtained in vitro is then integrated with the UVA data measured on human skin to generate a complete UV absorption spectrum.

d. Data Calculation and Verification

A computer uses specific calculation formulas to convert the fused spectral data into concrete numerical values such as SPF and UVA-PF. The entire process is validated through comparison with standards and statistical rules, ensuring the data meets predefined precision requirements.

Technical Boundaries and Industry Impact

The introduction of ISO 23698 is not merely an upgrade in testing methodology; it propels the development of sunscreen products towards higher efficiency, greater precision, and more humane practices. Its technical advantages include:

•   Significant Safety Enhancement: By replacing erythemal response with optical measurement, it eliminates the risk of causing sunburn to volunteers' skin during testing, reflecting stronger ethical consideration.

•   Rich Data Dimension and High Efficiency: Simultaneous output of SPF, UVA-PF, and CW allows for a comprehensive assessment of sun protection efficacy in a single test, greatly shortening the R&D cycle.

•   Enhanced Objectivity and Traceability: Reduces subjective errors from human erythema reading and improves inter-laboratory result comparability through standard calibration and optical equipment monitoring.

The widespread adoption of this technology will establish the efficacy data of sunscreen products on a more scientific, safer, and more credible foundation, marking the entry of sun protection testing into a new development stage centered on optical technology.

Product Recommendation

Solar Light's HDRS testing systems—the Poly602 and Mono602 models—comply with the ISO 23698 testing standard, providing efficient and reliable solutions for sunscreen product evaluation.

Core System Advantages

•   Rapid acquisition of SPF and UVA-PF results

•   Single measurement takes only 3-4 seconds (Poly602) / 30 seconds (Mono602 system)

•   No skin erythema response, total irradiation energy below international UV safety threshold

•   Subjects can participate in Hybrid Diffuse Reflectance Spectroscopy (HDRS) testing every 7 days

Core System Configuration

•   Poly602 / Mono602 HDRS Main Unit

•   LS1000 Solar Simulator

•   SPF290 UV Transmittance Analyzer

•   PMMA Test Plates

•   RestAssured Service, Maintenance & Warranty

As its authorized distributor in China, Aibotn provides testing systems and complete solutions that comply with sun protection testing standards. Feel free to contact us for more information!