Who should not take Teacrine

Teacrine is sold as a dietary supplement, and the label rarely has a full list of contraindications. However, it is a stimulating substance, close to caffeine, that stays in the body for a long time. For some people even a "mild" stimulant can be dangerous. The editorial team has analyzed who should avoid teacrine or use it only after consulting a doctor.

Where the contraindications come from

Teacrine is a purine alkaloid, structurally close to caffeine. Animal studies have shown its interaction with adenosine and dopamine receptors (Feduccia et al., 2012). This means that its effects touch the same systems as the action of caffeine: the nervous system, the cardiovascular system, sleep regulation.

Safety studies in humans, in particular the work of Taylor and colleagues (2016), were conducted on healthy adults without serious diseases. Neutral results regarding heart rate and blood pressure in this group do not automatically transfer to people with chronic illnesses.

Because of the absence of special studies in vulnerable groups, the contraindications for teacrine are formulated by analogy with caffeine and other stimulants and with regard to physiology. This approach is a standard practice of caution for poorly studied substances.

It is also important that teacrine is rarely taken on its own. Most products contain caffeine and other stimulants, so the contraindications of these components effectively extend to the whole product.

Cardiovascular diseases

People with heart-rhythm disorders — atrial fibrillation, frequent extrasystoles, long-QT syndromes — have an increased risk of complications from any stimulants. Even if teacrine itself acts more mildly than caffeine, in combined products the total stimulation can provoke an arrhythmia.

Uncontrolled arterial hypertension is another significant limitation. In people who are not habituated, caffeine can temporarily raise blood pressure, and teacrine most often comes together with it. For people with already high blood pressure such additional strain is undesirable.

Coronary heart disease, a past heart attack, heart failure, cardiomyopathies are conditions in which any increase in the load on the heart must be assessed by a cardiologist. Taking stimulating supplements on your own is unacceptable here.

Athletes with undiagnosed heart diseases deserve separate mention. Sudden cardiac events during exertion are often associated with hidden defects, and stimulants combined with intense work can be an additional trigger. Complaints of chest pain, fainting, or heart-rhythm disturbances during training are a reason to get examined, not to take supplements.

The nervous system, mental health, and sleep

People with generalized anxiety disorder, panic attacks, or social anxiety often tolerate stimulants poorly. In sensitive people caffeine can provoke panic attacks, and it is logical to expect a similar reaction to related substances.

Chronic insomnia is another reason to avoid teacrine. The substance remains in the body for a long time, and when combined with caffeine its elimination slows down (He et al., 2017). Even a morning dose can affect falling asleep in sensitive people.

Bipolar disorder and other conditions related to the dopamine system require special caution. Animal data suggest a dopaminergic component of teacrine's action, and stimulants in general can affect the course of such disorders.

Epilepsy is a condition in which any stimulants should be discussed with a neurologist. There are no direct data on teacrine, but high doses of methylxanthines can lower the seizure threshold.

• Anxiety and panic disorders.
• Chronic insomnia.
• Bipolar disorder and other mental conditions — only by a doctor's decision.
• Epilepsy — only after consulting a neurologist.

Pregnancy, children, and other special groups

During pregnancy the metabolism of caffeine slows significantly, and separate limits have been established for it. For teacrine there are no data on safety for the fetus at all, so pregnant and breastfeeding women should avoid it.

Children and adolescents are especially sensitive to stimulants. Teacrine has not been studied in them, and energy drinks and pre-workout complexes are not intended for this age group at all.

People with liver diseases may metabolize purine alkaloids more slowly, which prolongs their action. People with hyperthyroidism already have increased stimulation of the cardiovascular and nervous systems, and additional stimulants can intensify tachycardia and anxiety.

People with peptic ulcer disease or gastroesophageal reflux should consider that caffeine, with which teacrine is usually combined, can worsen symptoms. Caution is also needed for elderly people, who often take several medications at once.

Interactions with drugs and other stimulants

The most important interaction is with caffeine: it increases the exposure to teacrine. The total stimulant load should be assessed taking into account all sources, and for caffeine be guided by the EFSA recommendations — up to 400 mg per day for healthy adults.

Other stimulants — synephrine, yohimbine, amphetamine-like compounds, drugs for treating ADHD — intensify the effect on the heart and nervous system. Combining them with teacrine without medical supervision is not advisable.

Monoamine oxidase inhibitors, some antidepressants, and drugs that affect the dopamine system can theoretically interact with teacrine. There are no direct studies, so the decision should be made by a doctor.

Drugs that affect heart rhythm and blood pressure, as well as medicines whose metabolism depends on the liver enzymes that break down methylxanthines (for example, some fluoroquinolone antibiotics slow the elimination of caffeine), are a reason to consult before taking it.

Editorial conclusions

Teacrine is a stimulant, and its contraindications are similar to those of caffeine: heart diseases, uncontrolled hypertension, anxiety disorders, insomnia, pregnancy, and childhood.

Neutral results of safety studies concern healthy adults and do not extend to vulnerable groups, for which there are no data.

Special attention should be paid to the total stimulant load and interactions with drugs, since teacrine most often comes as part of combined products with caffeine.

We also recommend reading "Side effects of Teacrine," "Teacrine: forms of release and which to choose," and "How to take Teacrine: dosage, timing, duration."

References

1. Taylor L, Mumford P, Roberts M, et al. Safety of TeaCrine®, a non-habituating, naturally-occurring purine alkaloid over eight weeks of continuous use. J Int Soc Sports Nutr. 2016;13:2.
2. Feduccia AA, Wang Y, Simms JA, et al. Locomotor activation by theacrine, a purine alkaloid structurally similar to caffeine: involvement of adenosine and dopamine receptors. Pharmacol Biochem Behav. 2012;102(2):241–248.
3. He H, Ma D, Crone LB, et al. Assessment of the drug–drug interaction potential between theacrine and caffeine in humans. J Caffeine Res. 2017;7(3):95–102.
4. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific opinion on the safety of caffeine. EFSA J. 2015;13(5):4102.
5. Guest NS, VanDusseldorp TA, Nelson MT, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18(1):1.
6. Nehlig A. Interindividual differences in caffeine metabolism and factors driving caffeine consumption. Pharmacol Rev. 2018;70(2):384–411.