With ibuprofen that is indeed the case. 800 is the effective dosage, 400 doesn't do much.
Its does for me and most. Many studies have shown that higher doses do nto always = better treatment. Hell one of the worst things drug companies worry about now is placebo's. They have shown to work almost as well as some drugs themselves.
Now if you are obese then you may need a higher dose, but for most regular people that is not the case. Like I said before I took just 1 ibuprofen after my motorcycle accident.
<--- Use to work in Pharm