Best Fit Profiles
- muscle protein synthesis stimulation, particularly for older adults with blunted anabolic response
Muscle protein synthesis trigger
Leucine
Leucine is the primary branched-chain amino acid that triggers mTORC1-dependent muscle protein synthesis. The leucine threshold (minimum dose to trigger MPS) is critical for aging muscle, which requires higher doses than younger individuals.
Evidence Level A
Evidence and Risk Labels
Evidence A/B/C reflects research maturity, and risk levels reflect monitoring needs. These labels support comparison, not diagnosis or treatment decisions.
See full scoring guideClinical Snapshot
- Effect Size
- Large at threshold doses for MPS; foundational for muscle preservation in aging
- Safety
- Low Risk
Isolated leucine supplementation without other EAAs provides incomplete protein synthesis substrate; best as part of complete EAA or high-quality protein source.
Research Dosing
This reflects common ranges and protocols used in published studies, not personal medical advice.
- Typical Daily Dose
- 2-3 g per meal (as part of protein intake)
- Timing
- With each protein-containing meal
- Protocol Duration in Studies
- Long-term; ongoing as part of protein strategy
Leucine threshold for MPS in older adults is ~2.5-3 g per meal; whey protein naturally delivers this.