5 ms·

I always thought it was more about the constricting of blood vessels that caffeine causes, which reduces the blood supply that is a main cause of headaches. So

I always thought it was more about the constricting of blood vessels that caffeine causes, which reduces the blood supply that is a main cause of headaches. So it alleviates the underlying cause rather than reduces the pain.

tomjakubowski 4y ago
Caffeine dilates blood vessels - withdrawal will make them constricted
- tedunangst 4y ago
  Backwards. It's a vasoconstrictor.
  - felixg3 4y ago
    Exactly, and some types of headaches come from vasodilation (like migraine pain).
  - tomjakubowski 4y ago
    it's complicated... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003984/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003984/ "A mild and transitory vasoconstrictor effect exists, which depends mainly on the caffeine concentration in the VSMC. However, the main and predominant effect of caffeine on the vascular wall is vasodilating, acting equally on the VSMC directly or indirectly and also on the endothelial structure." The paper also says that withdrawal headaches are caused by vasodilation so I was wrong about that. "When you abruptly stop the consumption of caffeine in a habitual consumer, there is a greater number of available adenosine receptors, which potentiates the vasodilation produced by adenosine, causing the symptoms"