Quick Verdict
Whey Protein
Fast-digesting complete protein derived from milk. Richest natural source of BCAAs, especially leucine (key mTOR activat
Evidence: strong (800+ studies)
Caffeine
Most consumed psychoactive. Adenosine antagonist. Well-established ergogenic aid across nearly all exercise modalities.
Evidence: strong (1300+ studies)
Side-by-Side Comparison
| Whey Protein | Caffeine | |
|---|---|---|
| Category | protein | performance |
| Evidence Level | strong | strong |
| Studies | 800+ | 1300+ |
| Dosage | 20-40 g | 3-6 mg/kg |
Stack Compatibility
Whey Protein: Creatine, Casein (before bed), Dextrose (post-workout insulin spike)
Caffeine: L-theanine (1:2 ratio caffeine:theanine), Creatine, Tyrosine
Which Should You Choose?
Both serve different purposes. Choose based on your priority.