Optimal - The Blog

July 21, 2025

Anxious About Your Caffeine Intake?

Caffeine—found in coffee, tea, sodas, and energy drinks—helps people feel more awake by blocking certain brain receptors.

But when you drink too much (about four or more cups of coffee a day), it can make you feel anxious by speeding up your brain and stress responses.

Everyone reacts differently: some people get jittery more easily because of their genetics.

Common Beverage Sources of Caffeine

Brewed Coffee (Arabica): 30 mg per 100 mL
Espresso Coffee: 279 mg per 100 mL
Instant Coffee (soluble), diluted: 36 mg per 100 mL
Cappuccino: 32 mg per 100 mL
Green Tea, infused: 20 mg per 100 mL
Black Tea (English Breakfast/Earl Grey): 18 mg per 100 mL
Yerba Mate, Chimarrão: 26 mg per 100 mL
Iced Tea: 6 mg per 100 mL
Energy Drink: 30 mg per 100 mL
Cola Soda: 9 mg per 100 mL

Optimal Takeaways

Keep It Moderate: Aim for less than 400 mg of caffeine daily (around four small cups of coffee) to avoid anxiety.
Watch Your Dose: Big doses of caffeine are linked to feeling more anxious; smaller amounts usually aren’t a problem.
Know Yourself: Some people are more sensitive to caffeine and may feel anxious even at lower amounts.
Talk to Your Provider: If you’re anxious, mention how much caffeine you drink—your healthcare provider can help you find the right balance.

References

Liu, Chen et al. “Caffeine intake and anxiety: a meta-analysis.” Frontiers in psychology vol. 15 1270246. 1 Feb. 2024, doi:10.3389/fpsyg.2024.1270246 This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).

Rocha, Pedro Lucas de Amorim et al. “Development of a Caffeine Content Table for Foods, Drinks, Medications and Supplements Typically Consumed by the Brazilian Population.” Nutrients vol. 14,20 4417. 21 Oct. 2022, doi:10.3390/nu14204417 This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).