Branched-Chain Amino Acids
BCAAs (leucine, isoleucine, valine) are essential amino acids heavily marketed for muscle building, but the hype exceeds evidence. B-GRADE for aerobic exercise metrics (small improvement, 3 studies, 235 participants). C-GRADE for ammonia (mixed), fatigue symptoms in specific sports. D-GRADE for blood glucose, cortisol, anaerobic capacity, and adrenaline (no effect). CRITICAL: BCAAs alone do NOT increase muscle protein synthesis - ALL essential amino acids must be present. Protein from food or whey provides BCAAs plus the other EAAs needed. Leucine alone may be more anabolic than the BCAA trio due to absorption competition.
Quick Answer
What it is
BCAAs (leucine, isoleucine, valine) are essential amino acids heavily marketed for muscle building, but the hype exceeds evidence. B-GRADE for aerobic exercise metrics (small improvement, 3 studies, 235 participants).
Key findings
- Grade B: Aerobic Exercise Metrics (Aerobic Exercise Performance)
- Grade C: Ammonia (Muscle Recovery)
- Grade C: Fatigue Symptoms (Ski Performance)
Safety
No specific caution or interaction language was detected in the current summary/outcome notes.
ℹ️ Quick Facts: Branched-Chain Amino Acids
Quick Facts: Branched-Chain Amino Acids
- Best Evidence:Grade B
- Conditions Studied:12
- Research Outcomes:56
- Grade B Findings:2
- Key Effect:Aerobic Exercise Performance
Detailed Outcomes
Evidence by Condition
Best grade per condition (each condition may have multiple outcomes)
Research Citations (11)
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