这不仅仅是简单的头发稀少，而是新头发生长的问题。

It is not simply a lack of hair, but rather a problem with the new hair that is made.

youdao

对我来说这个缺陷就是我的头发，或者说是因为头发稀少。

For me it's my hair, or lack thereof.

youdao

王平：一是头发稀少，人又长得黑，因此看起来比较老相，大家都叫他“张大爷”；

Wang Ping: Firstly, he is a man with thin hair, and dark skin. Thus, he looks older than his age. Therefore, people like to call him "Uncle Zhang".

youdao