L-Leucine
L-Leucine is an essential branched-chain amino acid that plays a critical role in muscle protein synthesis, particularly beneficial for muscle growth and recovery in athletes, the elderly, and those on plant-based diets.
Evidence last reviewed: 20 Apr 2026
Moderate evidence supports L-leucine's effectiveness in enhancing muscle protein synthesis, especially in untrained midlife women. There are also low-quality studies suggesting benefits for specific health conditions, but more research is needed to confirm broader applications.
anemia improvementpatients with transfusion-dependent Diamond-Blackfan anemia · CohortLow
L-leucine improved anemia and growth in patients with Diamond-Blackfan anemia.
quality of life improvementpatients with Niemann-Pick disease type C · RCTModerate
N-acetyl-L-leucine improved symptoms and quality of life in Niemann-Pick disease type C patients.
muscle protein synthesisuntrained midlife women · RCTModerate
L-leucine supplementation coupled with resistance training improved muscle protein synthesis.
Athletic Performance and Muscle Growth
Combining Ecdysterone with Leucine can enhance athletic performance and support muscle growth. Ecdysterone is an anabolic agent that promotes muscle growth, while Leucine is a key amino acid for muscle protein synthesis.
Forms & usage▾
Take 2-5 grams daily, ideally around workouts or meals.