Caffeine: Silent Ally or Foe? What Your Brain Isn't Telling You

Caffeine is one of the world's most widely consumed stimulants, found in coffee, tea, chocolate, energy drinks, and some medications. It works primarily by blocking receptors for adenosine, a brain molecule that signals fatigue. By blocking these receptors, it temporarily prevents the brain from "receiving" the signal to rest [1], [2]. The result: you feel awake, more alert, but it's not real energy—it's an illusion of alertness .

Biochemically, caffeine also stimulates the production of cortisol, dopamine, and norepinephrine [2], [3]. In small doses and in a well-regulated context, this can be beneficial. But consumed too early in the morning, or in excess, it unbalances the HPA (hypothalamic-pituitary-adrenal) axis and can, in the long term, disrupt energy metabolism, deep sleep, and even cardiovascular health [3].

What Regular Caffeine Consumption Hides

Tolerance to caffeine develops quickly. The more you consume, the less it stimulates you. You then move from occasional use to functional dependence . In other words: you no longer drink coffee to feel better, but to function at all [4], [8].

Side effects are numerous: blood sugar crash, anxiety, irritability, insomnia, or nighttime awakenings. One study showed that a dose taken even 6 hours before bedtime can reduce the amount of deep sleep [7]. Sensitive profiles—those who already suffer from chronic stress, anxiety, or unstable sleep—are most at risk [6].

Who should limit caffeine?

Some people are genetically slower at metabolizing caffeine, particularly those with a variation in the CYP1A2 gene [12]. Others, such as women in the luteal phase of their menstrual cycle, are physiologically more reactive to it [11]. People experiencing chronic fatigue or burnout should also be wary of caffeine: the additional cortisol stimulation it causes can worsen their hormonal imbalance [10].

The caffeine “reset”: regaining natural sensitivity

Taking a 7-14 day break may be enough to reset your adenosine receptors [13]. During this reset, it is recommended to stay well hydrated, incorporate adaptogens like tulsi or ashwagandha, use clean energy sources (like MCT C8 oil), and expose yourself to natural light first thing in the morning to naturally boost your cortisol [14].

A simple but underappreciated tip: avoid drinking coffee within an hour of waking up . Since cortisol is naturally high at this time, adding caffeine exacerbates it unnecessarily. Waiting 90 minutes allows for more respectful stimulation of your biological rhythms.

Dave Asprey and the biohacked vision of coffee

Biohacker Dave Asprey isn't against caffeine—he's reprogramming it. According to him, the problem isn't the molecule or the ritual , but how it's consumed . He offers the famous Bulletproof Coffee : a high-quality (mycotoxin-free) coffee blended with grass-fed butter and C8 MCT oil .

This mixture slows caffeine absorption, stabilizes blood sugar, and provides the brain with ketones , an alternative energy source to glucose [15], [16], [21]. The goal is to boost concentration and neurogenesis without causing a spike followed by a crash [17].

"It's not the coffee that's the problem, it's what you put in it, and when you drink it."
—Dave Asprey, The Bulletproof Diet

This approach aligns with the functional vision: stimulate without exhausting .

Alternatives to caffeine: fueling energy differently

Some substances act on the nervous system without disrupting the HPA axis :

• L-theanine + tyrosine : balance between mental clarity and calmness [18]

• Cordyceps, rhodiola : adaptogens that support physical and cerebral energy [19]

• DHA + EPA : regulators of neuronal inflammation and mood [20]

• MCT C8 : direct source of ketones for the brain [21]

• Citicoline : support for memory and concentration without nervousness [22]

These alternatives don't mask fatigue—they support the foundations of your real vitality .

Conclusion: Sustainable energy is cellular energy

Caffeine can be a tool, but it can also be a trap. Used without awareness, it camouflages the body's calls to slow down, repair itself, and breathe . It acts on the symptoms—not the causes.

At Vāhana, we believe that true performance begins when the nervous system is respected . Sustainable energy doesn't come from a shot of adrenaline, but from a profound balance between neurotransmitters, mitochondria, and hormones.

What if your next boost… was a break?

Scientific references

1. Fredholm BB, Bättig K, Holmén J, Nehlig A, Zvartau EE. Actions of caffeine in the brain with special reference to factors that contribute to its widespread use. Pharmacological Reviews. 1999;51(1):83–133.

2. Nehlig A. Is caffeine a cognitive enhancer? Journal of Alzheimer's Disease. 2010;20 Suppl 1:S85–S94.

3. Lovallo WR. Stress and Health: Biological and Psychological Interactions. Sage Publications; 2015.

4. Griffiths RR, Woodson PP. Caffeine physical dependence: a review of human and laboratory animal studies. Psychopharmacology. 1988;94(4):437–51.

5. Nawrot P, Jordan S, Eastwood J, Rotstein J, Hugenholtz A, Feeley M. Effects of caffeine on human health. Food Additives and Contaminants. 2003;20(1):1–30.

6. Smith A. Effects of caffeine on human behavior. Food and Chemical Toxicology. 2002;40(9):1243–55.

7. Drake C, Roehrs T, Shambroom J, Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine. 2013;9(11):1195–200.

8. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology. 2004;176(1):1–29.

9. Childs E, de Wit H. Personality and the acute subjective effects of d-amphetamine in humans. Journal of Psychopharmacology. 2006;20(4):471–81.

10. McEwen B.S. Protective and damaging effects of stress mediators. New England Journal of Medicine. 1998;338(3):171–9.

11. Temple JL, Bernard C, Lipshultz SE, Czachor JD, Westphal JA, Mestre MA. The safety of ingested caffeine: a comprehensive review. Frontiers in Psychiatry. 2017;8:80.

12. Cornelis MC, El-Sohemy A, Kabagambe EK, Campos H. Coffee, CYP1A2 genotype, and risk of myocardial infarction. JAMA. 2006;295(10):1135–41.

13. Kaplan GB, Greenblatt DJ, Ehrenberg BL, Goddard JE, Cotreau-Bibbo MM, Harmatz JS, Shader RI. Caffeine behavioral sensitization and cross-sensitization to d-amphetamine: role of dopaminergic and noradrenergic mechanisms. The Journal of Pharmacology and Experimental Therapeutics. 1993;265(3):1332–41.

14. Huberman A. Using Light to Optimize Health. Huberman Lab Podcast. Episode on circadian alignment.

15. Asprey D. The Bulletproof Diet: Lose up to a Pound a Day, Reclaim Energy and Focus, Upgrade Your Life. Rodale Books; 2014.

16. Clarke DD, Sokoloff L. Circulation and energy metabolism of the brain. In: Basic Neurochemistry. 1999.

17. Koppel SJ, Swerdlow RH. Neuroketotherapeutics: A modern review of a century-old therapy. Neurochemistry International. 2018;117:114–25.

18. Nathan PJ, Lu K, Gray M, Oliver C. The neuropharmacology of L-theanine (N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent. Journal of Herbal Pharmacotherapy. 2006;6(2):21–30.

19. Panossian A, Wikman G. Effects of adaptogens on the central nervous system and the molecular mechanisms associated with their stress-protective activity. Pharmaceuticals. 2010;3(1):188–224.

20. Bazinet RP, Laye S. Polyunsaturated fatty acids and their metabolites in brain function and disease. Nature Reviews Neuroscience. 2014;15(12):771–85.

21. Courchesne-Loyer A, Croteau E, Castellano CA, St-Pierre V, Vandenberghe C, Hennebelle M, et al. Increased brain uptake and oxidation of ketone bodies in aged rats. PLoS One. 2013;8(10):e78594.

22. McGlade E, Yurgelun-Todd D. The effect of citicoline supplementation on attention and psychomotor performance in healthy female adults. Journal of Attention Disorders. 2012;16(7):601–8.