Buying shampoo can be overwhelming – there are so many brands to choose from, across a huge range of prices. Some brands promise to repair and nourish our hair, while others promise to strengthen and add volume. But are any of these claims true? Do we even need shampoo at all?

购买洗发水可能会让人不知所措——品牌众多，价格差异巨大。 一些品牌承诺修复和滋养我们的头发，而另一些品牌则承诺加强和增加头发的体积。 但这些说法都是真的吗？ 我们甚至需要洗发水吗？

Since long before shampoo was invented – some say in India – our bodies have been producing sebum – an oil-like substance. Sebum stops our skin from getting dry, manages the health of our scalp and makes our hair shiny. But it also collects dirt, and, if left untouched for too long, sebum can cause our hair to become greasy. There are no disadvantages from a health perspective to letting our hair be greasy, says Eleanore Richardson, Trichologist at Fulham Scalp and Hair Clinic, but many people choose to wash their hair regularly for aesthetic reasons.

早在洗发水发明之前——有人说是在印度——我们的身体就一直在产生皮脂——一种油状物质。 皮脂阻止我们的皮肤变干，管理我们头皮的健康，让我们的头发闪亮。 但它也会积聚污垢，如果长时间未接触，皮脂会使我们的头发变得油腻。 Fulham Scalp and Hair Clinic 的毛发学家埃莉诺·理查森 (Eleanore Richardson) 说，从健康的角度来看，让我们的头发油腻并没有什么坏处，但许多人出于审美原因选择定期洗头。

And so we reach for the shampoo bottle. Shampoos contain a group of chemicals called surfactants. They grab the dirt and grease from the surface of our hair, meaning when we rinse away the shampoo, we also wash away the grease and dirt. But, as Laura Waters, who's a Professor of Pharmaceutical Analysis in the School of Applied Sciences at Huddersfield University, points out, 'some surfactants work too well' and take the natural oils out of the hair, as well. More expensive shampoos may contain less harsh surfactants, but – adds Laura Waters – the type of shampoo doesn't really matter. 'It's on our hair very briefly and gets washed away'. It's the conditioners and styling products that we use after the shampoo that make a bigger difference to the texture and feel of our hair.

所以我们伸手去拿洗发水瓶。 洗发水含有一组称为表面活性剂的化学物质。 它们抓住我们头发表面的污垢和油脂，这意味着当我们冲洗掉洗发水时，我们也洗掉了油脂和污垢。 但是，正如哈德斯菲尔德大学应用科学学院药物分析教授劳拉·沃特斯 (Laura Waters) 所指出的那样，“一些表面活性剂效果太好”，而且还会去除头发中的天然油脂。 更昂贵的洗发水可能含有较少的刺激性表面活性剂，但 - 劳拉沃特斯补充道 - 洗发水的类型并不重要。 “它在我们的头发上停留的时间非常短，然后就会被冲走”。 正是我们在洗发后使用的护发素和定型产品对我们头发的质地和触感产生了更大的影响。

Of course, the more we put onto our hair, the more we need to cleanse it off, creating a vicious circle. So, yes, it seems we do have a need for shampoo, but we also shouldn't expect it to be a miracle cure. And, finally, next time you're in a shampoo aisle, remember that hair is made up of dead protein cells and that, sadly, not even the most expensive shampoo can bring them back to life.

当然，我们涂的越多，就越需要清洗，形成恶性循环。 所以，是的，我们似乎确实需要洗发水，但我们也不应期望它是一种灵丹妙药。 最后，下次你在洗发水货架时，请记住头发是由死去的蛋白质细胞组成的，遗憾的是，即使是最昂贵的洗发水也无法让它们起死回生。

词汇表

brand 品牌
repair 修复
nourish 滋养
strengthen 使强韧，强化
volume 数量
sebum 皮脂
oil-like substance 类似油类物质
scalp 头皮
shiny 有光泽的
greasy 油腻的
aesthetic 美观的
chemical 化学品
surfactant 表面活性剂
surface 表层
rinse 冲洗，清洗
harsh 刺激性强的
conditioner 护发素
styling product 美发定型产品
texture （发）质，质地
cleanse 清洁，清洗
miracle cure 灵丹妙药