Leucine Importance
Leucine Is The Key
One of the branched chain amino acids. Triggers the building of new muscle protein.
When it reaches a sufficient concentration in the blood and muscle, it activates a pathway (mTOR) that starts the process of building.
Older adults develop anabolic resistance. Muscle becomes less sensitive to the same protein synthesis that works well in younger people.
Raising the leucine content of a meal helps overcome that resistance.
Leucine-focused meals have repeatedly been shown to better preserve and build muscle in people over 60.
mTOR stands for mechanistic Target of Rapamycin (previously known as mammalian Target of Rapamycin).
It is a key protein kinase that acts as a central regulator of cell growth, proliferation, protein synthesis, and metabolism in response to nutrients (especially amino acids like leucine), growth factors, and energy status.
Per meal target: 3 grams leucine
Chicken breast: up to 2.5 grams of leucine
3 large eggs: 1.5 grams
Cottage cheese: 2 grams
Most plant proteins are low in leucine
Hit the leucine threshold multiple times per day
Muscle remains sensitive for 24-48 hours after training
Prioritize leucine-rich proteins at each meal and around training.
Spread protein across 3-4 meals, avoid a single protein dump.
In a calorie surplus or deficit, leucine still helps tip the balance toward muscle retention or gain, rather than loss.
Leucine is not a magic pill. Total protein, training stimulus, energy balance, and recovery still matter. But leucine remains the single most influential amino acid for the muscle building signal.
The protein shake I drink needs to be higher in leucine. This pea protein product from NOW is high in leucine.
SCOOPS NEEDED TO ACHIEVE mTOR
