护发素的英文译词是 "hair conditioner"。来源是来自英文单词 "condition"，指的是 "使处于良好状态"。

例句：

I always use hair conditioner after I wash my hair to keep it healthy and smooth.

我每次洗完头发后都会用护发素来保持头发健康和柔顺。

She has a sensitive scalp, so she uses a special hair conditioner that is gentle and moisturizing.

她有敏感的头皮，所以她使用特殊的护发素来滋润头皮。

I love the way my hair feels after using a hair conditioner – it's so soft and manageable.

我喜欢用护发素后我的头发的感觉 - 它非常柔软和易管理。