How can caffeine be harmful if it has been used for centuries to increase awareness and focus? The Chinese drank tea for medicinal purposes, while the Buddhists used caffeinated green tea to facilitate long meditations and self-cultivation. Ethiopia used coffee for concentration, and South America consumed yerba mate for its energizing properties to aid mystical rituals and give hospitality. Even though caffeine has these amazing benefits, your body may not respond to caffeine the best way. To determine if caffeine is right for you is through a caffeine intolerance test.

caffeine intolerance test

Caffeine is now most commonly used for sleepiness and in the form of coffee. While other forms of caffeine can consumed, all are helpful when it comes to optimizing our performance.

Caffeine continues to be a topic of debate whether it is worth consuming for its stimulating benefits. Until recently, healthcare professionals relayed messages that caffeine is bad for your health and often leads to drowsiness. The determining factor varies on if you have a caffeine intolerance or not.

Thankfully to science, there is an improved caffeine intolerance test based on your genetics and unique biochemistry.


DNA Caffeine Intolerance Test

With just a swab of the mouth, saliva can pinpoint any DNA markers to indicate how sensitive you are to caffeine – whether beneficial or harmful – based on how long caffeine stays in your body.

Some are fast caffeine metabolizers and find caffeine more beneficial for them. Others are slow metabolizers and clear caffeine inefficiently.

DNA Caffeine Intolerance Test

What gene determines if you are sensitive to caffeine?

Individuals with a variant of the CYP1A2 gene may find that caffeine consumption leads to sleep disturbances, anxiety, digestive issues, and hormonal issues. Those with this gene variant cant produce enough CYP1A2 enzyme to clear caffeine out of the bloodstream quickly. In addition, slow metabolizers have a higher risk for nonfatal heart attacks or high blood pressure with high amounts of caffeine intake. (1)

By drinking more than 3 cups of coffee per day with the CYP1A2 gene variant, you may be increasing your risk of:

  • a heart attack by 2-fold or more
  • hypertension by 3-fold

In addition, those with a variant of the CYP3A4 gene can determine if they are more sensitive due to the inefficiency of detoxifying caffeine. Sensitivity to caffeine can leave one feeling jittery and have a buildup of reactive oxygen species. Reactive oxygen species are chemically reactive molecules known to cause inflammation which leads to disease.

On the other hand, individuals missing these variants will process caffeine more efficiently and reduce the risk of heart attack and hypertension, and for the most part, can safely consume caffeine.

Keep in mind genes are not a diagnosis but rather a signpost. Even though our genes can indicate how well our bodies metabolize caffeine, we never treat the gene. Instead, we have a clear direction of what signs to look for or additional bloodwork to evaluate.

If you have either the CYP1A2 or CYP3A4 variant, then what? Determine if you have caffeine intolerance symptoms.


Caffeine sensitivity symptoms


If you’re shaking after a mid-morning coffee, then you may have an intolerance. However, other habits that can cause the jitters include not getting enough sunlight during the day (~10-60 minutes) or too much artificial light at night.

Headache or Migraine

Typically, a headache following caffeine consumption is related to dehydration. Caffeine is a diuretic and will have you taking an extra trip to the bathroom or two. So drink plenty of fluids before consumption. I would even include a half teaspoon of sea salt as the neurons in your brain require an ionic flow. What that means is neurons need sodium. They need magnesium and potassium.


If you struggle to fall asleep after consuming caffeine from 2 pm or onwards, then you could be intolerant to caffeine. Caffeine floating in the bloodstream triggers the cortisol secretion to elevate. Cortisol is a healthy hormone when released at its highest levels early in the day after we wake up. However, when you start seeing peaks in cortisol toward night time can create sleep disturbances.


Factors that influence caffeine tolerance 

  • Sleep patterns and quality of sleep
  • Time of caffeine consumption
  • Dietary factors
  • Ongoing stress
  • Medications (Id est birth control)
  • Intestinal microbiome

Benefits of caffeine

  • Enhanced cognitive health
  • Alertness
  • Guarding against age-related cognitive decline
  • Overall mood
  • Rapid visual information processing
  • Decreased fatigue
  • Both coffee and green tea contain antioxidants

How caffeine reacts in our bodies

  • Bind to receptors on the surface of nerve cells increases their activity.
  • Stimulate the pituitary gland to release hormones.
  • Prompt the adrenal glands to make the fight or flight hormone adrenaline and cortisol. Cortisol and adrenaline powerfully regulate energy, focus, enhanced learning, and immune system functions.

Caffeine works to make us more alert by several mechanisms. One of which reduces the activity of a molecule called adenosine, which plays a role in sleepiness. However, caffeine competes with adenosine for the adenosine receptor antagonist and creates states of arousal.

When caffeine binds with the adenosine receptor, adenosine cannot drop naturally. After the caffeine wears off, adenosine is still floating around to cause the morning crash. The workaround is to delay consumption an hour or two after waking up to allow adenosine to drop naturally. (2)

Caffeine also increases dopamine release in the brain, a hormone that creates a sense of well-being. Dopamine also improves learning, focus and reduces stress. This increase in dopamine may be behind caffeine addiction.

My favorite food or drink to unlock these benefits

Black Coffee (~100 mg caffeine)
Matcha (~96 mg caffeine)
Loose green tea (~35 mg caffeine)
Yerba Mate (~85 mg caffeine)
Kombucha (~15 mg caffeine)
Chocolate (~12 mg caffeine)
Thorne Memoractiv supplement (50 mg caffeine)

Bottom line

Caffeine can either promote or stifle cognition based on your genes, the timing of consumption, and other variants. Without a gene test, the next best determining factor is adequate sleep to contribute to cognitive health and function. For most of us, a morning cup of tea or coffee is still helpful for us to access alertness and focus, as long as we don’t rely on caffeine.