BCAA (Branched-Chain Amino Acids)

⚡ Overview

BCAAs include three essential amino acids — leucine, isoleucine, and valine — which make up roughly 35% of muscle amino acids.
They are popular for their role in protein synthesis and fatigue reduction, but their usefulness depends heavily on nutritional context.

🟢 Proven Benefits

• Energy support: may slightly delay fatigue during long workouts (>60 min).
• Muscle preservation: useful during fasting or protein restriction, where they help reduce muscle breakdown.
• mTOR activation: leucine acts as an anabolic signal, though its effect is temporary without other essential amino acids (EAA).

🟡 Ambiguous Evidence

• Isolated BCAAs cannot fully stimulate muscle protein synthesis without all essential amino acids.
• Post-workout recovery results are highly variable.
• Minimal to no effect on muscle growth if total protein intake is already sufficient.

🔴 What It Does Not Do

• Does not significantly improve performance or strength in well-nourished athletes.
• Does not prevent catabolism if calorie and protein needs are already met.
• Does not outperform whey isolate for muscle gain.

💊 Dosage & Timing

General guidance — not a prescription

• 5–10 g before or during exercise (ratio 2:1:1 leucine:isoleucine:valine).
• Most useful when:
  • Training fasted or for >90 min.
  • On a low-calorie or strict vegan diet.
• Limited benefit if consuming ≥1.6 g/kg/day of complete protein.

💡 Tip: EAAs or whey isolate provide stronger anabolic effects at a similar cost.

⚠️ Safety

• Generally safe and well tolerated.
• Very high intakes (>30 g/day) may unbalance amino acid ratios and raise ammonia levels in sensitive individuals.

⚠️ Risks & Interactions

• Excess BCAA use may disrupt the balance of essential amino acids.
• May interact with hypoglycemic or metabolic medications.

✅ Better Alternatives

• Whey protein: naturally provides BCAAs within a complete amino acid profile.
• Full EAAs: stronger effect on muscle protein synthesis.
• Protein snacks: eggs, Greek yogurt, tofu, or full meals are more complete options.

📚 References

• Examine.com — BCAA Overview
• NIH/ODS — Amino Acids & Metabolism
• Health Canada — Amino Acid Supplement Guidance