mTOR (mammalian target of rapamycin) is a cellular signaling molecule. mTOR is involved with critical functions that support cell survival and protein synthesis. A trigger for activating mTOR is the amino acid L-Leucine. When levels of L-Leucine rise, mTOR “flips the switch” of cellular protein production. The BCAAs, a key factor in 3:2:1 Hydration Base™, help to preserve and repair muscle through mTOR activation.