L-Leucine: Muscle Protein Synthesis & Recovery
1. What Is L-Leucine?
L-Leucine is an essential branched-chain amino acid (BCAA) that acts as a potent trigger for the mTOR pathway, the master regulator of muscle protein synthesis. Rapidly absorbed post-ingestion, leucine raises plasma levels within 30 minutes, directly signaling muscle cells to initiate protein building.
2. Clinically Demonstrated Benefits
2.1 Triggering Muscle Protein Synthesis
A single 2.5 g dose of L-Leucine in young adults increased mixed muscle protein synthesis by 30% over 3 hours compared to placebo.
2.2 Sparing Muscle During Caloric Deficit
In a 10-day energy deficit study, 5 g leucine supplementation preserved lean mass by reducing proteolysis markers by 20% versus control.
2.3 Enhancing Recovery & Strength Gains
Combined with whey protein, 3 g additional leucine accelerated strength recovery and reduced soreness in resistance-trained men over 8 weeks.
3. Optimal Dosage & Timing
3.1 Dose
2.5–3 g pure L-Leucine per serving (≈0.05 g/kg body weight)
3.2 Timing
- Post-Workout (within 30 min): Maximize mTOR activation.
- Between Meals: Top off daily leucine threshold for continuous muscle support.
- Before Sleep: Pair with casein to sustain overnight protein synthesis.
4. Safety & Side Effects
L-Leucine is well tolerated up to 0.1 g/kg/day. High isolated doses (>10 g) may compete with other BCAAs for transport, but no serious adverse events have been reported in healthy adults
5. Where to Find L-Leucine in Maxine’s Burn
- Burn Protein: Delivers 3 g L-Leucine per scoop for rapid mTOR activation.
- Burn Whey & Collagen: High-leucine whey isolate blend.
- Burn Dessert Mousse: Indulgent recovery with added leucine.
