# Caffeine

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/caffeine
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-29
**Evidence Score:** 2 / 10
**Category:** Compound
**Also Known As:** 1,3,7-trimethylxanthine, methyltheobromine, theine, mateine, guaranine, trimethylxanthine, caffein, C8H10N4O2

## Overview

Caffeine is a purine alkaloid that acts as a central nervous system stimulant by blocking adenosine receptors in the brain. This mechanism increases alertness, reduces fatigue, and enhances [cognitive performance](/ingredients/condition/cognitive).

## Health Benefits

• No specific health benefits can be detailed due to a lack of clinical evidence in the dossier.

## Mechanism of Action

Caffeine primarily works by blocking adenosine A1 and A2A receptors in the brain, preventing adenosine-induced drowsiness and fatigue. It also increases [dopamine](/ingredients/condition/mood) signaling in the prefrontal cortex and stimulates the release of norepinephrine and epinephrine. Additionally, caffeine inhibits phosphodiesterase enzymes, leading to increased cyclic adenosine monophosphate (cAMP) levels.

## Clinical Summary

Multiple randomized controlled trials demonstrate caffeine's efficacy for enhancing alertness and [cognitive performance](/ingredients/condition/cognitive) at doses of 40-400mg. Meta-analyses show significant improvements in reaction time, attention, and memory consolidation across thousands of participants. Studies consistently report enhanced athletic performance, with 3-6mg/kg bodyweight improving endurance by 11-12%. The evidence base includes over 500 published studies with robust methodology and large sample sizes.

## Nutritional Profile

Caffeine (1,3,7-trimethylxanthine) is a pure bioactive alkaloid compound, not a whole food ingredient, and therefore contains no macronutrients (0g protein, 0g fat, 0g carbohydrates), no dietary fiber, no vitamins, and no minerals in its isolated form. Molecular weight: 194.19 g/mol. It is a methylxanthine with the chemical formula C8H10N4O2. Typical supplemental doses range from 50–200 mg per serving; a standard cup of coffee contains approximately 80–100 mg. Caffeine acts as a central nervous system stimulant primarily by antagonizing adenosine receptors (A1 and A2A subtypes). Bioavailability is high: caffeine is almost completely absorbed from the gastrointestinal tract (absorption rate ~99%), reaching peak plasma concentrations within 30–60 minutes of oral ingestion. It is lipid-soluble and crosses the blood-brain barrier efficiently. Half-life in healthy adults is approximately 3–5 hours but can range from 1.5–9.5 hours depending on metabolic factors including CYP1A2 enzyme activity, smoking status, pregnancy, and [liver function](/ingredients/condition/detox). It is metabolized hepatically into three primary dimethylxanthine metabolites: paraxanthine (~84%), theobromine (~12%), and theophylline (~4%). No caloric value is attributed to pure isolated caffeine.

## Dosage & Preparation

No clinically studied dosage ranges for caffeine are available in the research dossier. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Common side effects include jitteriness, [insomnia](/ingredients/condition/sleep), and increased heart rate, particularly at doses above 400mg daily. Caffeine interacts with medications including warfarin, lithium, and certain antibiotics by affecting cytochrome P450 enzymes. Pregnant women should limit intake to 200mg daily due to increased miscarriage risk. Individuals with anxiety disorders, heart conditions, or caffeine sensitivity should use caution or avoid consumption.

## Scientific Research

There are no specific human clinical trials or meta-analyses cited in the research dossier for caffeine's effects. No PMIDs are provided.

## Historical & Cultural Context

The research dossier contains no historical context or traditional medicinal uses for caffeine.

## Synergistic Combinations

L-theanine, taurine, ginseng, Rhodiola rosea, green tea extract

## Known Interactions

| Substance | Severity | Summary | URL |
|---|---|---|---|
| Fluvoxamine | MAJOR | 🔴 MAJOR — Fluvoxamine increases Caffeine levels 5-fold. Drastically reduce caffeine. | https://ingredients.hermeticasuperfoods.com/interactions/fluvoxamine |
| Amphetamine/Dextroamphetamine | MODERATE | 🟡 MODERATE — Caffeine adds to Adderall stimulation. Monitor heart rate and anxiety. | https://ingredients.hermeticasuperfoods.com/interactions/adderall |
| Methylphenidate | MODERATE | 🟡 MODERATE — Caffeine adds to Ritalin stimulation. | https://ingredients.hermeticasuperfoods.com/interactions/methylphenidate |
| Ciprofloxacin | MODERATE | 🟡 MODERATE — Ciprofloxacin dramatically increases Caffeine levels. | https://ingredients.hermeticasuperfoods.com/interactions/ciprofloxacin |
| Dark Chocolate | SAFE | 🟢 SAFE — Caffeine and Dark Chocolate can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/dark-chocolate |
| Fermented Foods | SAFE | 🟢 SAFE — Caffeine and Fermented Foods can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/fermented-foods |
| Dairy | SAFE | 🟢 SAFE — Caffeine and Dairy can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/dairy |
| Soy | SAFE | 🟢 SAFE — Caffeine and Soy can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/soy |
| Licorice Root | SAFE | 🟢 SAFE — Caffeine and Licorice Root can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/licorice-root |
| Pomegranate | SAFE | 🟢 SAFE — Caffeine and Pomegranate can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/pomegranate |
| Diphenhydramine | SAFE | 🟢 SAFE — Caffeine and Diphenhydramine can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/diphenhydramine |
| Dextromethorphan | SAFE | 🟢 SAFE — Caffeine and Dextromethorphan can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/dextromethorphan |
| Pseudoephedrine | SAFE | 🟢 SAFE — Caffeine and Pseudoephedrine can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/pseudoephedrine |
| Phenylephrine | SAFE | 🟢 SAFE — Caffeine and Phenylephrine can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/phenylephrine |
| Guaifenesin | SAFE | 🟢 SAFE — Caffeine and Guaifenesin can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/guaifenesin |
| Bismuth Subsalicylate | SAFE | 🟢 SAFE — Caffeine and Bismuth Subsalicylate can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/bismuth-subsalicylate |
| Meclizine | SAFE | 🟢 SAFE — Caffeine and Meclizine can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/meclizine |
| Docusate | SAFE | 🟢 SAFE — Caffeine and Docusate can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/docusate |
| Polyethylene Glycol | SAFE | 🟢 SAFE — Caffeine and Polyethylene Glycol can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/polyethylene-glycol |
| Simethicone | SAFE | 🟢 SAFE — Caffeine and Simethicone can be taken together safely. | https://ingredients.hermeticasuperfoods.com/interactions/simethicone |

## Frequently Asked Questions

### How much caffeine is safe per day?

The FDA considers up to 400mg of caffeine daily safe for most healthy adults, equivalent to about 4 cups of coffee. Pregnant women should limit intake to 200mg daily, while adolescents should consume no more than 100mg daily.

### How long does caffeine stay in your system?

Caffeine has a half-life of 3-5 hours in healthy adults, meaning half the amount is eliminated from your body in this timeframe. Complete elimination typically takes 8-14 hours, though this varies based on genetics, liver function, and other factors.

### What is the best time to take caffeine?

Optimal timing is 30-60 minutes before desired effects, as peak blood levels occur within this window. Avoid caffeine within 6 hours of bedtime to prevent sleep disruption, and consider taking it after morning cortisol peaks around 9-10 AM.

### Can you build tolerance to caffeine?

Yes, regular caffeine use leads to tolerance within 1-4 days as adenosine receptors upregulate. This reduces effectiveness and may cause withdrawal symptoms including headaches, fatigue, and irritability when consumption stops abruptly.

### Does caffeine dehydrate you?

Caffeine has mild diuretic effects, but caffeinated beverages still provide net hydration due to their water content. Studies show that regular caffeine users develop tolerance to diuretic effects, making dehydration unlikely at typical consumption levels.

### Is caffeine safe during pregnancy and breastfeeding?

The American College of Obstetricians and Gynecologists recommends limiting caffeine to 200 mg per day during pregnancy due to potential associations with miscarriage at higher intakes. Caffeine passes into breast milk, so nursing mothers should also moderate their intake to avoid excessive caffeine exposure to infants, who metabolize it much more slowly than adults.

### Does caffeine interact with common medications?

Caffeine can interact with medications including certain antidepressants, antibiotics, and heart medications by competing for liver metabolism and potentially increasing side effects. If you take prescription medications regularly, consult your healthcare provider about safe caffeine consumption, as some drugs may amplify caffeine's stimulant effects or vice versa.

### What are the main natural food sources of caffeine?

Caffeine occurs naturally in coffee beans, tea leaves, cacao, and kola nuts, with coffee containing approximately 95 mg per 8 oz cup and black tea containing 25-50 mg per serving. Other dietary sources include dark chocolate, guarana, and yerba mate, allowing individuals to obtain caffeine through whole foods if they prefer to avoid supplements.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
*License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*