L-Leucine is the essential amino acid most responsible for muscle protein synthesis.

L-Leucine is the essential amino acid most responsible for muscle protein synthesis. Consuming ample L-leucine during workouts stimulates and fuels optimal muscle gains. It also combats muscle oxidation (burning) from intense exercise.*

  • Increases and fuels muscle protein synthesis and ATP production*
  • Combats muscle oxidation (burning) from intense exercise*
  • Jumpstarts the recovery process after intense training*
  • Allows the athlete to train harder and recover faster*


L-leucine is an amino acid that's the most potent activator of muscle protein synthesis.

When cells "sense" the presence of leucine, it signals them to increase the production/release of the master regulator of protein synthesis (mTOR).

As we get older, we get partially "resistant" to leucine. Accordingly, older adults need twice as much supplemental leucine as their younger counterparts to approximate similar levels of muscle-protein synthesis (MPS).

However, older and younger adults have exhibited increased MPS when given supplemental leucine, especially when taking less-than-optimal dietary amounts of protein.

Leucine also regulates blood sugar, increases growth hormone (GH), improves recovery, and increases glycogen stores in muscle after exercise-induced damage.

  1. Rieu I et al. Leucine supplementation improves muscle protein synthesis in elderly men independently of hyperaminoacidaemia. J Physiol. 2006 Aug 15;575(Pt 1):305-15
  2. Drummond MJ et al. Leucine-enriched nutrients and the regulation of mammalian target of rapamycin signalling and human skeletal muscle protein synthesis. Curr Opin Clin Nutr Metab Care. 2008 May;11(3):222-6.
  3. Meijer AJ et al. Amino acid signalling and the integration of metabolism. Biochem Biophys Res Commun. 2004 Jan 9;313(2):397-403.
  4. Protein sparing produced by proteins and amino acids. Nutr Rev. 1976 Jun;34(6):174-6.
  5. Stipanuk MH. Leucine and protein synthesis: mTOR and beyond. Nutr Rev. 2007 Mar;65(3):122-9.
  6. Crowe MJ et al. Effects of dietary leucine supplementation on exercise performance. Eur J Appl Physiol. 2006 Aug;97(6):664-72.
  7. Mero A. Leucine supplementation and intensive training. Sports Med. 1999 Jun;27(6):347-58.

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*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.