BCAAs – branched chain amino acids
These include leucine, isoleucine, and valine. Taking BCAAs activates the mTOR pathway. mTOR inhibition extends life span in multiple organisms. A 5 g dose is taken by athletes after a hard workout to repair muscles. But taking a 5 g dose activates the mTOR pathway. Activating the mTOR pathway may decrease lifespan.
Beta-hydroxy-beta-methyl butyrate (HMB) is a metabolite derived from leucine. Under normal conditions ~5% of leucine is converted to HMB and there is experimental evidence supporting that supplementation of this metabolite plays a role in increased performance and muscle hypertrophy.Oct 4, 2013
2015 – Review of many leucine studies: Beta-hydroxy-beta-methylbutyrate (HMB), a metabolite of the branched-chain amino acid leucine, has been investigated as a potential supplement to improve muscle quality; Beta-hydroxy-beta-methylbutyrate supplementation contributed to preservation of muscle mass in older adults. HMB supplementation may be useful in the prevention of muscle atrophy induced by bed rest or other factors.
Leucine has recently been shown to prevent sarcopenia in the elderly.
It has also been discovered in 2021 that a daily dose of BCAAs, specifically leucine was tested, activated muscle cells in people over 27 to regain their ability to divide. In humans, muscle cells no longer divide after around age 27. So body building then only increases the size of existing muscle cells, but does not cause new cells to form. On the other hand, muscle cells which are not used die and become fat cells, which is why older athletes who stop working out look so fat.
