✓ No active regulatory warningsFDA MedWatch, EMA EudraVigilance, WHO VigiBase, WADA Prohibited List · 2026-05-29
📰Read the full Caffeine (Anhydrous) evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ PURE CAFFEINE POWDER: 1 tsp = potentially lethal dose [1]
⚠ Pregnancy: <200 mg/day (ACOG) [1]
⚠ Adenosine cardiac stress test: withhold caffeine 24 hours [1]
⚠ CYP1A2 genetics: fast metabolizers benefit most [2]
⚠ Ephedra + caffeine = deaths reported [1]
ℹ️ Not obtained from food. Not applicable — this is a food/additive in its own right, not a nutrient with a daily dietary target.
🔬 Lab interpreter
ℹ️ No validated blood test. There is no established laboratory test to assess status or guide dosing for this ingredient. Clinical response and symptoms are the practical guide.
⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Caffeine is THE most evidence-based ergogenic aid (ISSN position stand). 3–6 mg/kg improves endurance 2–4%. Cognitive benefits are the most consistent. PURE POWDER IS LETHAL (1 tsp = ~5 g). CYP1A2 genetics determine individual response. L-theanine + caffeine is the optimal cognitive stack. <200 mg/day in pregnancy [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: Specific dosage data under clinical review
👦 Pediatric: See guidance
AAP recommends against caffeine for children and adolescents [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: 30–60 min pre-exercise or pre-cognitive demand [2].
💊 With food: With or without food [1].
🚫 Avoid: Pure powder. Ephedra. >400 mg/day (most adults). Evening (insomnia) [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['Caffeine capsules/tablets (100–200 mg)', 'preferred', 'Precise dosing. Safe [1].'] | Standard | Check label | |
| ['Coffee', 'common', '~80–100 mg/cup. Also provides chlorogenic acids [1].'] | Standard | Check label | |
| ['PURE CAFFEINE POWDER', '', 'EXTREMELY DANGEROUS — FDA warning. 1 tsp = lethal dose. DO NOT USE [1]'] | Standard | Check label |
3 Common questions
Is 400 mg/day safe? ▼
For most healthy adults: yes (FDA). Individual sensitivity varies enormously due to CYP1A2 genetics. Pregnant: <200 mg/day [1].
Pure caffeine powder — how dangerous? ▼
EXTREMELY. 1 teaspoon = ~5,000 mg = potentially lethal. FDA issued warning against bulk pure caffeine powder. Stick to measured capsules or coffee [1].
Does caffeine tolerance reduce performance benefits? ▼
Partial tolerance develops to alertness/mood effects. Performance benefits (exercise) appear to persist even with habitual use, though some studies suggest caffeine withdrawal + re-introduction may maximize acute effect [2].
4 Clinical evidence
Strong
Endurance performance: meta-analyses — 3–6 mg/kg improves time trial performance 2–4% [2]. Strength: modest improvement in 1RM and power output [2]. Cognitive: improved alertness, reaction time, attention (most consistent effect) [1]. ISSN position stand: effective ergogenic aid [2]. FDA: 400 mg/day generally safe for adults [1]. HIGH
Moderate
Fat oxidation: increases fat oxidation during exercise [2]. Headache: caffeine is an FDA-approved analgesic adjuvant (in Excedrin, etc.) [1]. Parkinson: observational association with reduced risk [1]. CYP1A2 genetics: fast metabolizers benefit more from caffeine for exercise [2]. MODERATE
Insufficient
5 Safety, toxicity & adverse events
Absolute contraindications
✕ Pure/anhydrous powder is extremely potent — a teaspoon can be a lethal dose; do not use unmeasured bulk powder
✕ Serious arrhythmia
Relative
⚠ Anxiety disorders, hypertension, arrhythmia — can worsen
⚠ Pregnancy — limit total intake
⚠ Concurrent stimulants, certain antibiotics (ciprofloxacin), theophylline
⚠ Avoid combining with synephrine/other stimulants
🚩 Red flags
● Patient using pure caffeine powder — lethal risk [1]
● Ephedra + caffeine combination — deaths reported [1]
● Pregnant patient >200 mg/day [1]
● Adenosine stress test scheduled — withhold 24 hours [1]
6 Interactions
Drug interactions
Ephedra/ephedrine Major
Mechanism: Synergistic cardiovascular stimulation. [1]
Effect: MI, stroke, death. [1]
Action: NEVER combine [1].
Adenosine (stress test) Major
Mechanism: Caffeine is an adenosine receptor antagonist. [1]
Effect: Invalidates adenosine stress test. [1]
Action: Withhold all caffeine 24 hours before test [1].
Ciprofloxacin Moderate
Mechanism: Cipro inhibits CYP1A2 → reduced caffeine clearance. [1]
Effect: Increased caffeine levels/toxicity. [1]
Action: Reduce caffeine during cipro course [1].
Supplement synergies
L-Theanine · 200 mg theanine + 100 mg caffeine
Caffeine (alertness) + theanine (calm, alpha-waves) = focused without jittery. Most evidence-based nootropic stack [1].
Caffeine (alertness) + theanine (calm, alpha-waves) = focused without jittery. Most evidence-based nootropic stack [1].
L-Tyrosine · 500–1,000 mg tyrosine
Catecholamine support under stress + caffeine alertness [1].
Catecholamine support under stress + caffeine alertness [1].
7 Regulatory
United States (FDA): GRAS at standard doses. FDA warning against pure powder. OTC analgesic adjuvant [1].
WADA: Not prohibited but monitored (>12 µg/mL urine was formerly a positive) [2].
ISSN: Position stand: effective ergogenic aid at 3–6 mg/kg [2].
8 Cite this page
Vancouver: Pkhakadze G. Caffeine (Anhydrous) — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 31]. Available from: https://supplement.ge/ingredients/caffeine-anhydrous/
APA 7th: Pkhakadze, G. (2026). Caffeine (Anhydrous) — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/caffeine-anhydrous/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: March 2027
References: 2 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Caffeine (Anhydrous) — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/caffeine-anhydrous/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG