成分表是一份合法文件，不是廣告。它按照各國化妝品法規，以濃度由高到低的順序排列每個成分。一旦你知道這個規則，你就獲得了一個任何廣告都無法給你的工具。
前五名成分決定一瓶產品的核心功效。好的精華液的前五名通常是：水（溶劑基礎）、保濕劑（如甘油）、滲透促進劑，以及一到兩個主要活性成分。如果前五名有酒精或香料，無論品牌聲譽多好，對敏感肌都需要謹慎。
1% 濃度是一個分水嶺。法規規定，濃度低於 1% 的成分，可以不按照濃度順序排列——換句話說，成分表後半段的成分幾乎都在 1% 以下。這意味著，你可以大致用「前半段」和「後半段」來判斷一個成分的劑量是否具有功效意義。
防腐劑通常出現在成分表的最後三分之一。這是正常的：防腐劑的有效濃度本來就很低（0.1% 到 0.5%），並不意味著它們不重要——沒有有效的防腐系統，產品在幾週內就會長菌。
識別成分的中英文對照，是進階的技能。積雪草苷是 Asiaticoside，神經醯胺是 Ceramide NP，玻尿酸鈉是 Sodium Hyaluronate。學會這些，你就不再需要依賴任何品牌的說法。
An ingredient list is a legal document, not an advertisement. Regulated by cosmetic law in every major market, it lists every ingredient in descending order of concentration. Once you understand this rule, you have a tool that no marketing copy can provide.
The first five ingredients define a product's core character. A well-constructed serum typically shows: water (solvent base), a humectant like glycerin, a penetration-supporting agent, and one or two primary actives. If alcohol or fragrance appears in the first five, approach with caution regardless of brand reputation.
One percent is a meaningful threshold. Regulations permit ingredients below 1% concentration to be listed out of order — meaning the second half of any ingredient list consists almost entirely of sub-1% components. This gives you a rough proxy: does this ingredient appear early enough to be at a therapeutic dose?
Preservatives typically appear in the final third. This is appropriate — effective preservation requires low concentrations (0.1% to 0.5%). Their position does not reflect their importance. Without adequate preservation, a formula would become contaminated within weeks.
Learning the cross-language names of key ingredients is an advanced skill worth developing. Asiaticoside is 積雪草苷. Ceramide NP is 神經醯胺 NP. Sodium Hyaluronate is 玻尿酸鈉. Once fluent, you no longer need to rely on any brand's claims.