十六烷基十八烷醇

化妆品成分专业报告：十六烷基十八醇

1. 基础信息 & 来源

INCI名称与化学标识

INCI名称: Cetearyl Alcohol (十六烷基十八醇)

化学名称: 混合的十六烷基醇和十八烷基醇

CAS号: 8005-44-5

化学式: 混合物，主要成分为 C₁₆H₃₄O (Cetyl Alcohol) 和 C₁₈H₃₈O (Stearyl Alcohol)

分子量: 约 242.45 g/mol (Cetyl Alcohol) 和 270.50 g/mol (Stearyl Alcohol)，实际为混合物范围

来源与生产

十六烷基十八醇是一种合成或半合成的脂肪醇混合物，通常通过以下方式获得：

• 主要来源: 从天然油脂（如椰子油、棕榈油）或石油衍生物经过氢化、水解等化工过程制得。现代化妆品工业中，植物来源（如椰子、棕榈）更为常见，以满足消费者对“天然”成分的需求 (依据：化妆品原料标准如USP、Ph.Eur.)。
• 生产流程: 油脂先经皂化或酯交换反应生成脂肪酸，再通过催化氢化还原为相应的醇，最后进行精馏和混合以控制十六醇与十八醇的比例。
• 纯度与等级: 化妆品级Cetearyl Alcohol通常纯度较高（>98%），不含重金属、微生物等杂质，符合ISO、EWG等安全标准 (参考：International Journal of Toxicology, Vol. 27, 2008)。

2. 皮肤作用机制与宣称功效 (科学依据为重点)

十六烷基十八醇 primarily functions as an emulsifier, thickener, and emollient in cosmetic formulations. Its effects are largely physical rather than biological, as it is not a primary active ingredient but a foundational component for product stability and texture.

功效总结表

宣称功效	作用机制	科学证据强度	关键研究发现简述	起效浓度范围 (典型配方)
乳化稳定	Acts as a co-emulsifier by forming liquid crystalline structures at the oil-water interface, reducing interfacial tension and preventing phase separation. It enhances the stability of emulsions (e.g., O/W or W/O) by promoting lamellar phases.	强 (Well-established) (依据：多项体外研究和配方实验)	Studies show that cetearyl alcohol, in combination with other emulsifiers like ceteareth-20, forms stable gels and creams with improved texture and long-term homogeneity.	1-5% (w/w)
增稠与质地改良	Increases viscosity of formulations by forming network structures in the continuous phase. It contributes to the creamy, luxurious feel of products without excessive greasiness.	强 (Well-established) (参考：Cosmetics & Toiletries magazine, formulation guidelines)	Rheological studies demonstrate its ability to modify flow properties, providing shear-thinning behavior ideal for topical application.	0.5-10% (w/w), depending on formulation type
润肤作用	Acts as an occlusive agent by forming a thin film on the skin surface, reducing transepidermal water loss (TEWL). It also fills in micro-crevices in the stratum corneum, leading to smoother skin feel.	中等 (Moderate) (依据：体外皮肤模型和消费者感知研究)	In vivo tests show modest improvements in skin hydration and barrier function when used in emulsions, though effects are secondary to primary humectants.	1-5% (w/w) for noticeable emolliency
抗氧化或抗衰老	No direct antioxidant or anti-aging mechanism. Any such claims are likely due to synergistic effects with other actives or the improved vehicle delivery. (注：此宣称缺乏直接证据，仅为配方辅助角色)	弱 (Weak) (来源：厂商宣称，无独立研究支持)	No specific studies confirm intrinsic antioxidant properties. Any benefits are indirect through formulation stability.	N/A

详细作用机制与证据：乳化稳定

十六烷基十八醇的乳化机制源于其两亲性结构：长碳链（疏水）和羟基（亲水）。在乳液中，它协助主要乳化剂（如非离子表面活性剂）形成多层液晶结构，这些结构增强界面强度，防止奥斯特瓦尔德熟化（Ostwald ripening）和 coalescence。研究通过偏振光学显微镜和X射线衍射证实了这些液晶相的存在 (依据：Journal of Colloid and Interface Science, Vol. 300, 2006)。典型浓度下（1-5%），它能显著提高乳液的离心稳定性和保质期。

详细作用机制与证据：润肤作用

作为润肤剂，十六烷基十八醇通过物理性 occlusive 作用减少水分蒸发。其碳链长度允许它 intercalate into the lipid matrix of the stratum corneum, temporarily improving barrier function. However, it is less effective than pure occlusives like petrolatum. Studies using corneometry show a 10-15% increase in skin hydration when formulated at 2-3% in creams, but this is often attributed to the overall formulation rather than cetearyl alcohol alone (参考：Skin Pharmacology and Physiology, Vol. 21, 2008).

3. 核心化学成分剖析

化合物类别	代表物质	基本性质
脂肪醇混合物	Cetyl Alcohol (十六醇, C16H34O), Stearyl Alcohol (十八醇, C18H38O)	外观: 白色蜡状固体或薄片 熔点: 48-55°C (混合物范围) 溶解度: 不溶于水, 可溶于乙醇、油脂 HLB值: ~15.5 (亲水亲油平衡, 偏亲水) 酸值: ≤2.0 mg KOH/g 碘值: ≤2.0 g I2/100g (依据：Merck Index and Cosmetic Ingredient Review data)
化学成分比例	Typically contains 20-80% cetyl alcohol and 20-80% stearyl alcohol, with trace amounts of other alcohols (e.g., myristyl alcohol)	The exact ratio affects melting point and texture: higher cetyl content gives a softer feel, higher stearyl provides harder consistency. This variability allows formulators to tailor properties for specific products.

4. 配方应用与协同效应

常见应用类型

• 乳霜和乳液: 作为 primary emulsifier or co-emulsifier in O/W systems, often used at 1-10% to provide stability and richness.
• 护发产品: 在护发素和发膜中作为增稠剂和调理剂，改善梳理性，浓度0.5-5%.
• 彩妆: 用于粉底、口红等，增强粘附性和滑爽感，浓度1-3%.
• 清洁产品: 偶尔在温和洁面乳中用作稠度调节剂，但较少见 due to its low solubility.

协同成分

• 与其他乳化剂: 与ceteareth-20、glyceryl stearate等协同，增强乳化效率 and create stable lamellar phases.
• 与润肤剂: 与dimethicone、squalane搭配，提供更轻质、不油腻的肤感。
• 与活性成分: 作为 delivery vehicle for actives like retinol or vitamin E, improving their stability and penetration by maintaining formulation integrity.
• 与防腐剂: 可能轻微影响防腐体系效能，需在配方中测试兼容性。

5. 安全性与适用性

安全性概况

• 皮肤刺激性: 一般认为无刺激性，但高浓度（>10%）可能引起轻微干燥或敏感，尤其在受损皮肤上 (依据：CIR评估，2008).
• 致敏性: 极低致敏风险，罕见过敏报告。Patch tests show negligible reactivity.
• 眼刺激性: 避免直接入眼，可能引起轻微刺激，但非严重 irritant.
• 系统毒性: 无系统毒性关注，经皮吸收极少，且代谢为天然脂肪酸。
• 环境安全性: 生物降解性好，无生物累积性， considered safe for environmental discharge at typical use levels.

适用皮肤类型

• 所有皮肤类型: 包括敏感皮肤， due to its mild nature.
• 干性皮肤: 受益于其润肤 properties.
• 油性皮肤: 可使用低浓度 formulations to avoid heaviness.
• 禁忌: 无特定禁忌，但 acne-prone skin should avoid very rich formulations containing high levels to prevent pore clogging (though it is non-comedogenic in most studies).

法规状态

Approved for use in cosmetics worldwide, including FDA (USA), EU Cosmetics Regulation (EC No 1223/2009), and China's CSAR. Listed as safe with no restrictions on concentration for leave-on and rinse-off products (参考：CIR Final Report, 2008).

6. 市场定位与消费者认知

市场角色

十六烷基十八醇 is positioned as a workhorse ingredient in cosmetic formulations, valued for its multifunctional properties rather than consumer-facing marketing. It is often labeled as "emollient" or "texturizer" rather than a star active.

消费者认知

• 一般认知: 大多数消费者不认识此成分，但倾向于 perceive it as safe due to its prevalence in "gentle" products like baby creams.
• clean beauty 趋势: 随着 clean beauty 运动，植物来源的十六烷基十八醇被推广为 "natural" alternative, though chemically identical to synthetic versions.
• 误解: 名称中的 "alcohol" 可能误导消费者以为它 drying, but it is actually a fatty alcohol with emollient properties. Education is needed to distinguish from drying alcohols like ethanol.

品牌使用情况

Widely used across mass-market and premium brands, from drugstore products (e.g., Cetaphil, CeraVe) to luxury skincare. It is rarely highlighted in marketing, instead being part of the base formula.

7. 总结与展望

总结

十六烷基十八醇 is a versatile, safe, and effective cosmetic ingredient primarily serving as an emulsifier, thickener, and emollient. Its scientific basis is strong for physical roles in formulation stability, but it lacks direct biological activity. It is a staple in cosmetics due to its reliability and mildness.

未来展望

• 可持续性: 未来趋势偏向使用可持续植物来源（如RSPO认证棕榈油）和绿色化学合成方法以减少环境 impact。
• 创新配方: 可能与新型乳化剂（如糖脂类）结合，开发更轻质、高稳定性的制剂。
• 消费者教育: 需要更多教育区分脂肪醇与挥发性醇，以消除误解。
• 研究方向: 进一步探索其在屏障修复中的辅助作用，以及与其他活性物的协同递送机制 (来源：当前化妆品研究趋势).