It works very well on me. Since I have rarely headaches, and if yes, there is always a good reason for them. Usually either big hangover, or exhaustion from long and intense effort in mountains, ie climbing Matterhorn 6 hours straight no stops, or similar effort on Mont Blanc that took 11 hours, both coupled with drinking too little&#x2F;sweating too much -&gt; dehydratation. Just drinking plenty afterwards doesn&#x27;t remove headache, just makes it a bit less intense. I pop the pill, and in 20 mins it&#x27;s over.<p>Maybe if causes for your headache are different, the effect might not be so quick &amp; effective.