Why does caffeine give me charlie horses in my back? It only happens if I drink several cups of regular coffee (not decaffeinated). When I stopped drinking things with caffeine, the charlie horses went away.
A: I must admit, I’ve never heard of this reaction to caffeine, but I suspect one of two causes for these symptoms.
You may be just plain allergic to caffeine and this is your particular — albeit peculiar – reaction. The small amounts of caffeine in decaffeinated coffee may not be enough to trigger the reaction.
Another possibility is that you are deficient in calcium. We know that caffeine causes an increase in urinary excretion of calcium. Normally this is problematic over the long haul; but if your calcium levels are already low, the caffeine may send you below your threshold. You could try taking a calcium and magnesium supplement for 1-2 months, then try taking caffeinated coffee again. However, the best option may be to avoid caffeine altogether.