Quick Verdict
Caffeine
Most consumed psychoactive. Adenosine antagonist. Well-established ergogenic aid across nearly all exercise modalities.
Evidence: strong (1300+ studies)
Collagen Peptides
Hydrolyzed collagen (types I, II, III) for skin, joint, and connective tissue health. Provides glycine, proline, and hyd
Evidence: moderate (60+ studies)
Side-by-Side Comparison
| Caffeine | Collagen Peptides | |
|---|---|---|
| Category | performance | protein |
| Evidence Level | strong | moderate |
| Studies | 1300+ | 60+ |
| Dosage | 3-6 mg/kg | 10-20 g |
Stack Compatibility
Caffeine: L-theanine (1:2 ratio caffeine:theanine), Creatine, Tyrosine
Collagen Peptides: Vitamin C, Hyaluronic Acid, Glycine, Magnesium
Which Should You Choose?
Caffeine has stronger evidence (1300+ studies).