> For the complete documentation index, see [llms.txt](https://helpcenter.tpandco.jp/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://helpcenter.tpandco.jp/docs/definition-of-words/nono/seramidoceramide.md). # セラミド（ceramide） ### **セラミドとは** セラミドは皮膚・爪の角質層に存在する脂質で、細胞間を埋める主要成分。バリア機能と保湿を担います。 #### **爪とキューティクルの構造** 爪（爪甲）は主にケラチンででき、層間にわずかな脂質を含みます。キューティクル（甘皮）周辺の皮膚は角質層を持ち、セラミドが細胞間脂質として存在します。 #### **主な働き** 1. **保湿・水分保持** ：水分を引き寄せて保持し、爪の乾燥・割れ・二枚爪を防ぎます。 2. **バリア機能の強化** ：洗剤・アセトン・水によるダメージから爪と周辺皮膚を守ります。 3. **キューティクルの柔軟性維持** ：乾燥によるひび割れ・ささくれを防ぎ、柔軟さを保ちます。 4. **爪の柔軟性・弾力維持** ：脂質バランスを整え、もろさを軽減します。 #### **特に有効なシーン** * 頻繁な手洗い・消毒によるダメージ * 冬季の乾燥・ささくれ対策 * 加齢による爪の薄化・脆弱化 * ジェル / アクリルネイル除去後 --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://helpcenter.tpandco.jp/docs/definition-of-words/nono/seramidoceramide.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.