Performance
Caffeine
Also known as: 1,3,7-Trimethylxanthine, Coffee extract, PURENERGY, caffeine co-crystal
Most widely used performance enhancer. Improves endurance, strength, and cognitive function through adenosine antagonism.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Caffeine product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Nutricost Caffeine + L-Theanine Capsules | 97 A | $0.53 |
| 2 | Nutricost Caffeine Capsules | 92 A | $0.12 |
| 3 | Transparent Labs Fat Burner | 92 A | $0.92 |
| 4 | Transparent Labs BULK Pre-Workout | 90 A | $1.67 |
| 5 | Thorne Memoractiv™ | 89 A | $2.33 |
| 6 | Nutricost Pre-Workout For Women Powder | 89 A | $0.73 |
| 7 | Zhou Nutrition Energy + Focus | 89 A | $0.35 |
| 8 | Nutricost Pre-Workout Complex | 89 A | $0.83 |
| 9 | Pure Encapsulations CaffPhenol | 88 A | $0.98 |
| 10 | Onnit Alpha BRAIN Black Label (80 ct) | 87 A | $6.25 |
| 11 | Thorne Brain Factors | 84 A- | $1.70 |
| 12 | NutraBio ThermoFuel V9 | 80 A- | $0.62 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Caffeine should I take?
The typical range is 100-400 mg daily; 3-6mg/kg for performance. Tolerance develops; cycle
When should I take Caffeine?
30-60 min before exercise. Optional.
Which form of Caffeine is best?
Capsules/tablets — Precise dosing. Other forms in the catalog: Powder, Coffee, Anhydrous, Natural (guarana, green tea).
Is Caffeine safe?
Commonly reported: Anxiety, Insomnia, Jitters, Dependency. Serious warnings: Overdose possible with powder. Safe
Which Caffeine supplement scores highest?
Nutricost Caffeine + L-Theanine Capsules, at 97/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Primary uses
- Energy
- Endurance
- Focus
- Strength
- Thermogenesis
- Fat oxidation
- Appetite suppression
What systematic reviews concluded
Outcomes that systematic reviews of Caffeine reached a verdict on: 5 with a benefit, 1 with harm reported, 2 unclear. Each is quoted from a review and linked to it on PubMed. How these were read.
Reviews found a benefit (5)
“Both low and moderate caffeine doses significantly reduced time-trial completion time relative to placebo.” PMID 42356375 · 2 reviews
“Acute caffeine ingestion confers a moderate ergogenic benefit for swimming performance (SMD = 0.57, 1.7% improvement)” PMID 42323844
“The pooled analysis revealed a small and significant ergogenic effect of caffeine supplementation on cycling performance for females (standardized mean difference = 0.21; 95% confidence interval [0.11, 0.29]), with high certainty of evidence.” PMID 42208612
“Available evidence most consistently supports small, outcome-specific benefits of acute caffeine for physical performance and reduced perceived exertion.” PMID 42588052
“Caffeine enhances attention and executive functions.” PMID 34978226
Harm reported (1)
“Caffeine intake in athletes increases the likelihood of side effects in a dose-dependent manner, with tachycardia, insomnia, abdominal discomfort, and anxiety being the most consistent.” PMID 42033594
Not enough to say: sport-specific skills and cognitive performance; high-intensity exercise performance with mouth rinse.
How it works
- Blocks adenosine receptors
- Increases catecholamines
- Enhances fat oxidation
- Central nervous system stimulant
Dosage
- Typical range
- 100-400 mg daily; 3-6mg/kg for performance
- Timing
- 30-60 min before exercise
- With food
- Optional
- Duration
- Tolerance develops; cycle
- Special populations
- Athletes, shift workers
Forms
- Capsules/tablets
- Powder
- Coffee
- Anhydrous
- Natural (guarana, green tea)
Safety
Common side effects
- Anxiety
- Insomnia
- Jitters
- Dependency
Contraindications
- Arrhythmias
- Severe anxiety
Products containing Caffeine
Top-scoring supplements in our catalog that list Caffeine on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Known interactions
Evidence notes
Proven ergogenic aid
Grade A: Multiple well-designed human trials support the main claims.
Cited research for Caffeine
Clinical studies referenced across Formulate guides that mention caffeine. Each links to the full study page with PubMed source + the guides that cite it.
- Hursel R, Viechtbauer W, Westerterp-Plantenga MS (2009)International Journal of Obesity
The effects of green tea on weight loss and weight maintenance: a meta-analysis
- Nobre AC, Rao A, Owen GN (2008)Asia Pacific Journal of Clinical Nutrition
L-theanine, a natural constituent in tea, and its effect on mental state
Caffeine compared head-to-head
Related in Performance
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.