Performance
Leucine
Also known as: L-Leucine, BCAA component
Primary amino acid triggering muscle protein synthesis. Can boost lower-protein meals.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Primary uses
- Muscle protein synthesis trigger
- Protein quality enhancement
How it works
- Primary mTOR activator
- Threshold amount triggers MPS (~2.5-3g)
- Most anabolic amino acid
Dosage
- Typical range
- 2.5-5g to boost a meal
- Timing
- With lower-protein meals
- With food
- With protein-containing meals
- Duration
- As needed
- Special populations
- Elderly, low-protein meals, plant-based eaters
Forms
- Powder
- Capsule
Safety
Common side effects
- Bitter taste
- GI upset
Contraindications
- MSUD
Products containing Leucine
Top-scoring supplements in our catalog that list Leucine on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Known interactions
Evidence notes
Well-established as MPS trigger
Grade A: Multiple well-designed human trials support the main claims.
Related in Performance
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.