Are You Caffeine Sensitive?

Are You Caffeine Sensitive?

Written by: Ryah Nabielski, MS, RDN

Globally, people drink over 1.6 billion cups of coffee each day! It’s the most popular beverage after water. Sure, coffee can taste amazing and help you start your day, but is it good for you?

Like many things in nutrition, coffee and caffeine’s health benefits are a hot debate topic. On the one hand, caffeine has established benefits for exercise performance and cognition. On the other hand, caffeine may trigger uncomfortable symptoms, especially in those with caffeine sensitivity.

The truth is caffeine works for some people and not for others. It’s highly individual. The wide variation in caffeine tolerance explains why one person can drink espresso before bed and sleep like a baby, and another will have insomnia from their morning coffee.

Keep reading to learn more about caffeine, caffeine sensitivity, and alternatives to caffeine for better health and exercise performance. This article will cover:

  • The basics of caffeine biochemistry and detoxification
  • Caffeine benefits, including exercise benefits
  • Potential downsides of caffeine use
  • Symptoms of caffeine sensitivity
  • Tips for boosting energy and performance without caffeine

Let’s dive in!

What is Caffeine?
Caffeine (1,3,7-trimethylxanthine) is a natural compound in dozens of plants, including coffee, tea, and cacao. Caffeine protects the plant from being eaten, as it is toxic to many insects and animals.

Caffeine is a well-known and extensively studied compound, famous for its stimulant properties that increase alertness. You’ll find it in coffee, tea, and other natural sources. It’s also added as an extract in soda, energy drinks, supplements, and medication.

Known as a psychoactive stimulant, caffeine blocks adenosine receptors in the brain and body, which allows for an increase in neurotransmitters, including dopamine, norepinephrine, and glutamate.

With regular caffeine use, the body builds tolerance, meaning you’ll need to consume more and more to have the same effects. Caffeine is habit-forming, and most users have an everyday habit compared to occasional use.

Caffeine Detoxification

The body absorbs caffeine efficiently. It quickly enters circulation and body tissues, including the brain. The body only excretes a small amount of caffeine (0.5 to 2%) in the urine. The rest (around 95%) goes to the liver for detoxification with a specific enzyme called cytochrome P450 1A2.

Your ability to detoxify caffeine and clear it from your body primarily depends on how this enzyme functions. Genetics plays a significant role in your rate of caffeine metabolism. Older adults and pregnant people tend to have slower caffeine detoxification and clearance.

There is so much individual variation in caffeine detoxification that the half-life (the amount of time it takes for blood levels to reduce by half) varies between two and 12 hours!

Potential Benefits of Caffeine

Caffeine may have short-term cognitive benefits to memory, alertness, motor skills, and reaction time. Over the long term, caffeine may be neuroprotective, protecting the brain against Alzheimer’s and other neurodegenerative diseases.

Indeed, some of the benefit of caffeine can be attributed to other compounds, like antioxidants, found in coffee, tea, and other plant-sources of caffeine.

Because caffeine interacts with blood vessels, either allowing for constriction and reduced blood flow or dilation and increased blood flow, it may be a helpful tool for migraine pain.

Caffeine and Exercise Benefits

Caffeine was established as an ergogenic aid in the early 1900s, meaning that it improves physical performance, which is why it’s a popular ingredient in pre-workout supplements.

Performance-enhancing supplements are used by athletes at all levels, from those who exercise for health benefits to elite athletes. Until 2004, Olympic athletes couldn’t use high amounts of caffeine (equivalent to five or six cups of coffee). Today, most athletes can legally use caffeine.

Potential Negative Effects of Caffeine Use

Caffeine stimulates the cardiovascular and central nervous systems. In high doses, it can cause:

  • Heart palpitations and arrhythmias
  • Dependency
  • Withdrawal symptoms
  • Caffeine intoxication, which in extreme cases can contribute to heart attack or death

As mentioned, you can build a tolerance to caffeine. Large doses may be more dangerous for someone who isn’t a regular caffeine consumer, such as a child drinking one or more energy drinks.

Those sensitive to caffeine because of slow or inefficient liver detoxification and clearance may experience more of the adverse side effects related to caffeine.

How To Know If You Are Caffeine Sensitive

Genetic testing can predict how you tolerate caffeine. However, most people can assess their
body’s reaction to caffeine, and sensitivity is often quite apparent.

Symptoms of caffeine sensitivity include:

  • Jitters
  • Racing heartbeat
  • Anxiety
  • Agitation
  • Sleep disruption (even when caffeine is consumed early in the day)
  • Headaches and migraines
  • Energy crashes and fatigue
  • Blood sugar imbalances and sugar cravings
  • Increased stress

You may experience sensitivity symptoms with even a small dose of caffeine, such as one cup of coffee or tea. Additionally, if you drink caffeine daily, you may notice withdrawal symptoms, like fatigue and headaches, when you skip a day. Withdrawal reactions are another sign of sensitivity.

Caffeine sensitivity symptoms are your body’s way of alerting you that caffeine may not be the best choice.

Note that caffeine sensitivity differs from an allergy to coffee, chocolate, or another caffeine-containing substance, which will produce allergic symptoms like hives, swelling, itchiness, and even anaphylaxis.

How To Boost Energy and Performance Without Caffeine

Limiting or avoiding caffeine intake helps keep your energy and mood stable if you are sensitive. You can choose lower caffeine options like decaffeinated tea, decaffeinated coffee, or chocolate if you tolerate those. Please note that the decaffeination process may add unwanted toxins to coffee and tea, so you’ll want to choose the highest quality options.

If you don’t use caffeine or are considering taking a break from it because you suspect a sensitivity, here are some ways to support balanced energy and increase exercise performance:

1. Focus on food. There is a perception that caffeine provides energy, but food does. Focus on eating regular, balanced meals to stabilize your blood sugar throughout the day.

2. Nourish your muscles. Maintaining or increasing muscle mass will improve energy, metabolism, and physical performance. One critical component is consuming enough protein.

3. Stay hydrated. If you are dehydrated, you’ll feel slow, sluggish, and tired, and your exercise performance will suffer. Learn more about hydration here.

4. Prioritize sleep. Inadequate sleep will negatively impact energy, mood, performance, and exercise recovery. If you aren’t sleeping well, taking a break from caffeine might improve things. For more sleep tips, check out this article.

5. Try caffeine-free pre-workout nutrients. Caffeine isn’t the only performance-enhancing option. You may find benefit from:

Citrulline – An amino acid known for enhancing nitric oxide, which improves
blood flow

Glutamine – An amino acid with anti-fatigue properties

Arginine – An amino acid that improves blood flow and endurance capacity

Tyrosine – An amino acid required for building muscle and producing dopamine and epinephrine to support cognitive function

Lysine – An amino acid that promotes human growth hormone production,
which supports athletic performance

Betaine – A natural source of the B vitamin choline that improves endurance and reduces perceived exertion and fatigue

Creatine – A well-known supplement for improving muscle mass, performance, and recovery. Learn more about the benefits of creatine supplementation here

Huperzia serrata – A neuroprotective extract from plant club moss that promotes cognitive function

Citicoline – A form of choline that supports brain health and mitochondrial

While these compounds may be supportive individually, they may be even more effective in a synergistic formula that combines multiple ergogenic ingredients. You’ll find this combination in Twenty2 Nutrition’s Stimulant-Free Pre-Workout, a powerful performance-enhancing supplement without caffeine.

If caffeine makes you feel jittery, triggers headaches, or tanks your energy, it’s okay to say goodbye and choose alternatives that truly make your body feel its best.

This article is for educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified healthcare provider before beginning a new supplement.

Ryah Nabielski, MS, RDN is a Registered Dietitian, functional nutritionist, writer, and recipe creator. Ryah helps clients use a natural, food-as-medicine approach to improve fertility, pregnancy, hormone balance, autoimmunity, and discover a healthy relationship with food and body. Learn more about Ryah and her private practice at