While vitamin tablets may be of some benefit to people

[ambitious-girl]

Are these two sentences correct?

While vitamin tablets may be of some benefit to people, they are unlikely to be effective in the fight against obesity.
While vitamin tablets may be to the benefit of people, they are unlikely to be effective in the fight against obesity.

 

[Raymott]

I'd prefer, "While vitamin tablets may be of benefit to some people ... "
Factually, it's more likely that vitamins benefit only some people (those who don't eat properly, or are sick in certain ways) than it is that they are of any benefit at all to most people. Therefore, I would use "some people" rather than "some benefit".
Of course, you could say "some benefit to some people".

2 doesn't sound right.