L-Leucine
L-Leucine is an essential amino acid and one of the three branched-chain amino acids (BCAAs). It is a potent nutrient-based signal to activate protein synthesis and the most potent activator of protein synthesis out of all the amino acids. L-Leucine is important for muscle formation and increases the rate of muscle protein synthesis (MPS) faster than any other amino acid, promoting more muscle mass. It also has a role in the production and maintenance of skeletal muscle mass and insulin production, which controls energy levels.
Studies have shown that L-Leucine can help lower weight without muscle breakdown and increase blood levels of high-density lipoprotein cholesterol (good cholesterol). However, long-term supplementation has largely failed to augment increases in muscle mass and strength in older adults. One study showed that during five weeks of strength and speed training, leucine supplementation of 50 mg/kg bodyweight/day, supplementary to a daily protein intake of 1.26 g/kg increased muscle mass.
The recommended dosage for L-Leucine is between 2,000-5,000mg for acute usage. It is best to take valine and isoleucine along with L-Leucine supplements to maintain the correct balance of these amino acids. It is safe to supplement with L-Leucine, but it is best not to exceed 500 mg per kg of body weight per day as it can cause increases in the levels of ammonia in the body, which can have a range of adverse effects.
There are no known potential side effects of L-Leucine when taken within the recommended dosage range. However, very high doses may cause low blood sugar (hypoglycemia) and pellagra, which can include skin lesions and hair loss.
Sources:
- https://examine.com/supplements/leucine/
- https://us.myprotein.com/thezone/supplements/leucine-dosage-benefits-side-effects/
- https://community.bulksupplements.com/l-leucine/
- https://www.urmc.rochester.edu/encyclopedia/content.aspx?contentid=Leucine&contenttypeid=19
- https://draxe.com/nutrition/leucine/
- https://pubmed.ncbi.nlm.nih.gov/10418071/
