Does caffeine shampoo have side effects?

Can caffeine shampoo cause headaches? It’s possible. Caffeine can be absorbed through the skin and into the bloodstream. So if you’re using a shampoo with caffeine and you have a headache, it could be the caffeine causing it. If you’re using a caffeine shampoo and you start to get headaches, try using it less often or switching to a different shampoo.