We're just going to say it: Caffeine isn't great for your period
While we typically don’t think much about caffeine beyond its ability to boost our energy, it does have other impacts on the body that are less obvious. Caffeine is a vasoconstrictor, so it constricts blood vessels in your body. It’s also a diuretic, which causes your body to lose fluid. And caffeine also affects your hormones, elevating cortisol and epinephrine, which are not unlike those experienced during an acute stress.
These factors help to explain why caffeine, as good of a friend as it may seem, can actually be worsening your period symptoms, including cramps, breast tenderness, bloating, headaches, tiredness, and anxiety. Try to lessen or avoid caffeine during your period to see if it helps to alleviate some of these symptoms. Yes, this includes coffee, but caffeine also hides in less obvious places too, such as your chocolate or your OTC medicine like Midol.
Ginger ale, herbal tea (hot or iced!), or plain water are great substitutes for settling your stomach and keeping you hydrated.