Hello, I checked phrases of “lack of sth” and “short of sth”. And my question is which expression sounds natural or both are fine? Please see below and do me a favor.

1. His problem is a lack of self-control.
2. He is short of self-control.

By the way, thanks for all your help and encouragement for me!

Question

Hello, I checked phrases of  “lack of sth” and “short of sth”. And my question is which expression sounds natural or both are fine? Please see below and do me a favor.

1. His problem is a lack of self-control. 
2. He is short of self-control.

By the way, thanks for all your help and encouragement for me!

Answer

In order to make them truly comparable, you need to use 'His problem is' with both.

His problem is a lack of self control.
His problem is he is short of self control.
You could also say:
His problem is he is short on self control.
His problem is he lacks self control.

I think all and any sound fine. I think 'short on' sounds more natural than 'short of' for character traits. I'd use 'short of' for more concrete things like money (but that might just be me).

Answer

#1 is best.

“Short ON self-control”

Answer

‘Short of’ means not reaching a level. It doesn’t really work with ‘self-control’ because you can have various levels of it.

Examples of ‘short of’
He’s two years short of 50. (He’s 48)
Short of getting a divorce, what can he do? (Without going to the level of getting a divorce …)
He tried to thru hike the PCT, but fell short of his goal by 800km. (The goal was to finish)

You could say something like 
He’s short of having enough self-control to achieve his objectives. (This is ok because here you’ve defined a level of self-control)

Best are:
He lacks self-control.
His problem is (that) he lacks self-control. (‘that’ is optional but I’d say it)