Evidence Comparison
Caffeine vs Green Tea Extract (EGCG)
For fat loss — which one has better evidence?
🏆 Winner for fat loss
Caffeine
Scores 45% vs 40% in evidence strength
Head-to-Head Comparison
100-400mg per day
250-500mg EGCG/day
30-60 minutes before exercise for performance
With meals (never on an empty stomach)
Coffee, caffeine pills, or pre-workout supplements. Pills offer more precise dosing.
Standardized green tea extract capsules
$5-30/mo
$10-25/mo
3 studies
3 studies
Evidence for fat loss
Caffeine
45%Caffeine increases metabolic rate by 3-11% and promotes fat oxidation, but the practical effect on body composition is modest and diminishes with tolerance.
Green Tea Extract (EGCG)
40%Meta-analyses show green tea catechins produce a small but statistically significant increase in fat oxidation and energy expenditure. Practical weight loss effects are modest (1-2 kg over 12 weeks on average).
Mechanism of Action
Caffeine
Caffeine's primary mechanism is competitive antagonism of adenosine receptors (A1 and A2A subtypes) in the brain. Adenosine normally accumulates throughout the day, promoting drowsiness and reducing neural activity. By blocking these receptors, caffeine prevents the sleep-promoting signal, resulting...
Read full review →Green Tea Extract (EGCG)
EGCG enhances fat oxidation and energy expenditure through inhibition of catechol-O-methyltransferase (COMT), the enzyme that degrades norepinephrine in adipose tissue. This prolongs norepinephrine signaling at the fat cell, promoting lipolysis and thermogenesis. EGCG also activates AMPK, inhibits l...
Read full review →⏱️ Time to Effect
Caffeine
Peak alertness and focus. Reduced perceived effort during exercise.
Strong stimulant effects if caffeine-naive. May experience jitters.
Tolerance builds to mood effects. Performance benefits partially maintained.
Habituated. Still improves performance but alertness boost is reduced. Consider cycling.
Green Tea Extract (EGCG)
EGCG and catechins absorbed. Mild thermogenic effect and fat oxidation increase.
Modest fat oxidation improvement (8-16%). Weight loss minimal without caloric deficit.
Maximum fat oxidation benefit. LDL cholesterol may decrease slightly.
Monitor liver enzymes. Discontinue if abdominal pain or jaundice develops.
🤝 Can You Take Both?
✅ These can generally be taken together safely. Many people stack both for complementary effects.
However, always start one at a time so you can identify which is responsible for any effects you notice.
📋 The Bottom Line
Choose Caffeine if:
- ✓ athletes seeking acute performance enhancement
- ✓ shift workers or those with early morning demands
- ✓ individuals seeking cognitive enhancement during demanding tasks
Choose Green Tea Extract (EGCG) if:
- ✓ those seeking modest metabolic support alongside diet and exercise
- ✓ individuals wanting antioxidant supplementation
- ✓ people who do not regularly drink green tea