Managing Caffeine Intolerance Symptoms | Lifelab Testing

Managing your caffeine intolerance and symptoms

Last Updated: 12th January 2023 · Written by Kate Young

Whether it’s through a morning cup of coffee, a pre-workout energy drink or even an afternoon chocolate bar, the vast majority of us consume caffeine as a daily habit. But could it be the root cause of our digestive complaints? If you’re suffering from a caffeine intolerance, this could definitely be the case. Read on as we explain how caffeine could be causing you more harm than good.

What is caffeine?

Caffeine is a psychostimulant consumed throughout the world. It’s commonly found in hot beverages such as coffee and tea, as well as chocolate and most energy drinks. It’s known for giving you that ‘buzz’ or boost of energy and used by many to help wake up in the morning. Caffeine has become such an everyday part of our culture that the vast majority don’t even give a second thought to the amount they consume. 

Benefits of Caffeine

Before we move on to discuss the drawbacks of caffeine and how to spot an intolerance, we’re going to give the drug its due and look at the benefits of caffeine. This isn’t a complete slam of the substance. 

  • Alertness – As you’ll be aware, ingesting caffeine is usually followed by a boost in alertness and concentration. Research has shown that caffeine alertness effect is the same, whether it’s 2 pm or 2 am [f]
  • Fat Burning – Interestingly, consuming caffeine encourages your body to dip into your fat stores and use lipids for energy, instead of doing whatever it can to preserve those stores ‌[j]. Studies have also measured the fat-burning benefits of caffeine and found that lean individuals can burn 150 calories from ingesting a single dose of 100mg [g].
  • Diabetes Prevention –  Researchers are still looking into this, but the evidence points towards caffeine being beneficial in preventing type 2 diabetes. Several studies have shown how the substance can help in reducing insulin sensitivity [d, e] and a few researchers have concluded that it could be helpful for those labelled ‘prediabetics’ [h, i].

That being said, caffeine does have its drawbacks, even for those who aren’t intolerant to it. 

Drawbacks of Caffeine

  • Anxiety disorders – As you may be aware since caffeine is a stimulant, it can worsen existing anxiety disorders. It makes perfect sense when you consider that caffeine makes your brain go into ‘fast mode’ and anxiety is a kind of fast-paced, negative thinking. It’s like adding fuel to the fire. Several studies have noted the exacerbating effects of caffeine for those with anxiety disorders [a]. One such study found a reduction in symptoms from simply diseasing consumption of the drug [c].  
  • Other Mental illness – Other studies have noticed a correlation between depression and caffeine consumption, but further research still needs doing to determine whether this is a causal relationship or not [b]
  • Sleep disturbances – As caffeine is a stimulant one of the major drawbacks of it is the effect it can have on your sleep. With a half-life of 3 to 5 hours, after a humble cup of tea at 5 pm, toting around 25mg of caffeine, you’d still have half of that caffeine running through your bloodstream come bedtime. With a more caffeinated beverage like say, a venti at Starbucks, you can easily expect more than ten times that amount – so it’s no wonder caffeine can have such an effect on our sleep.

Symptoms of Caffeine Intolerance

Now onto the devil that is caffeine intoleraNCE. Although often thought of as a ‘pick me up’ when that Monday afternoon is really beginning to drag, caffeine can cause serious issues for those whose bodies are not well adjusted to it. Caffeine intolerance, like most food intolerances, can be identified through a few symptoms;

  • Insomnia
  • Anxiety
  • Restlessness
  • Headaches
  • Fatigue
  • high blood pressure 
  • IBS symptoms

The main issue with identifying caffeine intolerance is that the symptoms are so similar to many other conditions. Many even mistakenly attribute their symptoms to withdrawal rather than intolerance, because of the time delay in the symptoms. But it’s very common for caffeine intolerance symptoms to begin hours or even days after consumption. 

How Much Caffeine Can You Drink?

Naturally, some people may be put off caffeine altogether after reading this, but the question is, how much caffeine is safe to drink before you develop an intolerance to it? As the summer comes around, you may find yourself consuming less hot drinks, but caffeine is still all around us, in chocolate (and chocolate flavoured foods), fizzy drinks and some sports drinks. The general consensus across the scientific and medical community is that 400mg of caffeine is relatively safe to have in one day, (around 4 homebrewed cups) but don’t let this trick you into assuming you don’t have an intolerance to the drug! An intolerance can develop regardless of how much you consume. 

What Else Could it be?

The most frustrating part is that it’s almost impossible to distinguish between a caffeine intolerance and any other food intolerance. All of those symptoms we mentioned earlier can be experienced through any food intolerance, and the only true way to accurately identify which food items are causing your symptoms is through testing.

At Lifelab, we offer the MyDNA test kit, which can help you understand how caffeine interacts with your body specifically. You can then figure out if your jitters or afternoon stomach issues have been caused by this addictive energiser, or you can hit two birds with one stone with our combo deal – Save £30 on a MyDNA kit, and determine if another food item is the culprit. There’s no reason to stay in discomfort when a life without these symptoms could be a simple test away. 


[a] Richards, G. and Smith, A. (2015). Caffeine consumption and self-assessed stress, anxiety, and depression in secondary school children. Journal of Psychopharmacology, [online] 29(12), pp.1236–1247. Available at: [Accessed 26 Mar. 2020].

[b] Jin, M.-J., Yoon, C.-H., Ko, H.-J., Kim, H.-M., Kim, A.-S., Moon, H.-N. and Jung, S.-P. (2016). The Relationship of Caffeine Intake with Depression, Anxiety, Stress, and Sleep in Korean Adolescents. Korean Journal of Family Medicine, [online] 37(2), p.111. Available at: [Accessed 26 Mar. 2020].

[c] Bruce, M.S. and Lader, M. (1989). Caffeine abstention in the management of anxiety disorders. Psychological Medicine, [online] 19(1), pp.211–214. Available at: [Accessed 26 Mar. 2020].

[d] Keijzers, G.B., De Galan, B.E., Tack, C.J. and Smits, P. (2002). Caffeine can decrease insulin sensitivity in humans. Diabetes care, [online] 25(2), pp.364–9. Available at: [Accessed 26 Mar. 2020].

[e] Shi, X., Xue, W., Liang, S., Zhao, J. and Zhang, X. (2016). Acute caffeine ingestion reduces insulin sensitivity in healthy subjects: a systematic review and meta-analysis. Nutrition Journal, [online] 15(1). Available at: [Accessed 26 Mar. 2020].

[f] Smith, A.P., Brockman, P., Flynn, R., Maben, A. and Thomas, M. (1993). Investigation of the effects of coffee on alertness and performance during the day and night. Neuropsychobiology, [online] 27(4), pp.217–23. Available at: [Accessed 26 Mar. 2020].

[g] Dulloo, A.G., Geissler, C.A., Horton, T., Collins, A. and Miller, D.S. (1989). Normal caffeine consumption: influence on thermogenesis and daily energy expenditure in lean and postobese human volunteers. The American journal of clinical nutrition, [online] 49(1), pp.44–50. Available at: [Accessed 26 Mar. 2020].

[h] van Dam, R.M. and Hu, F.B. (2005). Coffee consumption and risk of type 2 diabetes: a systematic review. JAMA, [online] 294(1), pp.97–104. Available at: [Accessed 26 Mar. 2020].

[i] Odegaard, A.O., Pereira, M.A., Koh, W.-P., Arakawa, K., Lee, H.-P. and Yu, M.C. (2008). Coffee, tea, and incident type 2 diabetes: the Singapore Chinese Health Study. The American journal of clinical nutrition, [online] 88(4), pp.979–85. Available at: [Accessed 26 Mar. 2020].

‌[j] Patwardhan, R.V., Desmond, P.V., Johnson, R.F., Dunn, G.D., Robertson, D.H., Hoyumpa, A.M. and Schenker, S. (1980). Effects of caffeine on plasma free fatty acids, urinary catecholamines, and drug binding. Clinical pharmacology and therapeutics, [online] 28(3), pp.398–403. Available at: [Accessed 26 Mar. 2020].

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