Missing,
In the 1800s Wild West, there were people called "Snake Oil Salesman" who traveled by covered wagon and sold magic potions that promised to easily solve all kinds of ailments .
They were mostly scams.
Today the same con artists exist but they travel by way of TV and Internet.
It is not that many herbal health foods don't have benefits, but 2-3% extra benefit will not give most people the results they seek.
It is much like Rogaine for hair loss.
Yes, legally they can sell it because clinically it does grow a small amount of hair.
But realistically, it does not create a cosmetically full head of hair that will satisfy the user.
The real answer ?
I have never seen a case where a combination of low net carb -lean protein diet + resistance training + cardio followed at least 3 times per week has not benefited a person.
On average, for people who have a fair amount of body fat to lose -- the normal results are 35-40 lbs lost in 4-5 months.
That is a healthy loss of about 2 lbs per week.
These days I tend to focus more on the needs of people over 40 as I myself am in my 50s -- but the basic principles apply to all ages.