A BIOCHEMISTRY textbook sometimes feels like essential reading when shopping for wrinkle-reducing products. Their labels list molecules like retinoids(类视黄醇), antioxidants(抗氧化剂), peptides(肽类) and exfoliating acids. The names might be familiar, but does anyone know what they do? Many of the claims that they will make skin appear more youthful rely on company-funded studies or consumer surveys rather than rigorous clinical evidence. Yet a handful of ingredients do have a solid scientific backing.
购物抗皱产品时，一本生物化学教科书有时感觉像是必读之物。产品标签上列出类视黄醇、抗氧化剂、肽类和去角质酸等分子。这些名字可能耳熟能详，但有人知道它们的作用吗？许多声称能让皮肤看起来更年轻的论断依赖于公司资助的研究或消费者调查，而非严格的临床证据。然而，确实有少数成分有坚实的科学依据。
Older-looking skin comes about via two distinct processes: the passage of time and environmental damage caused by ultraviolet (UV) light, pollution and smoking. All of these harm the collagen and elastin fibres in the extracellular matrix(细胞外基质), the skin’s structural scaffolding, causing wrinkles and sagging. Around 80% of ageing in white skin is caused by UV exposure(紫外线暴露), according to Abigail Langton, a dermatology researcher at the University of Manchester—the melanin(黑色素) in darker skin provides some degree of protection.
看起来更老的皮肤由两个不同过程导致：时间流逝，以及紫外线（UV）、污染和吸烟造成的环境损害。所有这些都会损害细胞外基质（皮肤的结构支架）中的胶原蛋白和弹性蛋白纤维，导致皱纹和松弛。根据曼彻斯特大学皮肤学研究员Abigail Langton的说法，白种人约80%的衰老由紫外线暴露引起——较深肤色中的黑色素提供了一定程度的保护。
If your wrinkles worry you, then the ingredient with the strongest scientific backing that might help is tretinoin(维A酸), also known as all-trans retinoic acid. A derivative of vitamin A, it was originally developed as a treatment for acne, but in the mid-1980s dermatologists noticed that patients who used it had fewer wrinkles as well as fewer spots. Studies of skin biopsies, as well as non-invasive skin imaging, revealed that tretinoin thickens the epidermis(表皮), the skin’s outer layer, making it look smoother and improving fine lines. It also stimulates collagen production in the dermis(真皮), the layer that sits just under the epidermis. This seems to partly restore the extracellular matrix and reduce wrinkles.
如果皱纹让你担忧，那么科学证据最强的可能有助于改善的成分是维A酸，也称为全反式视黄酸。作为维生素A的衍生物，它最初被开发用于治疗痤疮，但在20世纪80年代中期，皮肤科医生注意到使用它的患者皱纹和斑点都减少了。皮肤活检以及非侵入性皮肤成像研究显示，维A酸增厚表皮（皮肤的外层），使其看起来更光滑，改善细纹。它还刺激真皮（紧贴表皮下的层）中的胶原蛋白产生。这似乎部分地恢复了细胞外基质，减少皱纹。