It’s clear there are benefits of consuming caffeine: alertness and increased dopamine, that is why it is so widely consumed and why we use a little in our blends too.
But caffeine is a double edged sword. These benefits also come with some negative side effects. Some of them are more obvious to us, or well known - jitters, headache, upset stomach. But some of them aren’t always so obvious, a can have a real impact on our health, and ultimately our energy levels too.
1) Caffeine reduces blood flow:
Optimal blood flow enables the right nutrients to be taken to the right places, at the right time. Caffeine has been shown to reduce blood flow to the brain by ~30% (!). This is also why you may find yourself having a headache when caffeine's effects wear off. A few hours after caffeine ingestion, the blood vessels around your brain will begin to open up , causing a rapid increase in blood flow to the brain + pressure on the surrounding nerves.
2) Caffeine increases cortisol
Cortisol is our body's primary stress hormone. Usually, it is increased during the 'fight or flight' response - i.e. when you are in danger/ high stress situations. It impacts nearly every organ in the body, and impacts most systems, from the nervous system to the immune system. Increasing your body's cortisol is one of the mechanisms behind caffeine's alerting benefits, but long term exposure to excess cortisol can have negative health impacts.
3) Caffeine shrinks your hippocampus
This is the part of your brain that is responsible for memory and learning. Regular intake of caffeine has been found to cause significant changes in the gray matter in the brain, particularly the hippocampus, according to a 2021 study. Although the change in size doesn't seem to be permanent in this study, drinking high amounts of coffee (>6 cups a day) has been linked with a higher risk of dementia in various other studies.
Another example of the hidden side effects of caffeine comes from Matthew Moulding, founder of The Hut Group, who own myProtein, Lookfantstic, cultbeauty, and other huge brands. A very successful man and business, who recently opened up about his health on LinkedIn.
[Source: LinkedIn/Matthew Moulding]
He fell into the bracket of never feeling any caffeine side effects - not even the good ones apparently! That lead to his caffeine tolerance becoming incredible high (consuming ~30 shots a day). While he didn’t think it was impacting him, it turns out it was impacting his health in other ways - through his blood pressure and cholesterol. Once identifying this and cutting out caffeine, both blood pressure and cholesterol returned to normal levels within 4 weeks.
While you may think consuming that much caffeine is un-relatable, there is one last piece of the story that contributes to the less fun side of caffeine….the news revealed how much caffeine content can vary across different coffee chains and types. It was found that you could nearly exceed the maximum recommended dose from just 1 small costa cappuccino. 
That’s why we test the caffeine content of every single one of our blends. Mission are the only tea company to do this, so you know exactly what you're putting into your body.
