I have a slight suspicion that every time I consume something with caffeine it has a specific effect on me.
A good cup of black or green tea: Slight headaches at some times.
A cup of coffee (from work coffee machine): Depending on strenght slight attention issues or headaches.
A cup of coffee from a coffee shop which roasts its own coffee: One time a bit of stronger attention issues than the work coffee.
I usually notice it right away after consuming.
But I also have a very strong issue with staying hydrated.
Usually drink 0.5-1l per day until I notice the usual dehydrated-headache or when I am really focused and loosing it at times.
Usually it’s less prevelant at evening/night times.
Caffeine at any dose gives me anxiety and restlessness. At too high of a dose (which is basically equivalent to a large cup of coffee at home or a normal Starbucks coffee) I get heart palpitations and panic spirals.
I haven’t intentionally had caffeine in five years.