It hasn’t lost any effectiveness for me.
I’ll take 400 mgs. for a regular headache, or if it’s a sinus headache (and I’m using Sine-Aid or Sudafed), I’ll take the regular dose, and that works just fine, but when I feel a migraine coming on, if I pop four or five Advil liqui-gels real quick, most of the time, it will work. When they don’t work, and a migraine breaks through, I have Imitrex.
My neuro said the ibuprofen has less side effects than aspirin and Tylenol, and works better for headaches, so that’s why I use it.