Leucine – The Key to Muscle Building and Recovery After 40
Why your protein shake may no longer work — and how 5 grams of leucine per serving can change everything.
Why your protein shake may no longer work — and how 5 grams of leucine per serving can change everything.
You train regularly. You eat well. Maybe you drink a protein shake every day.
And yet: Your muscles barely grow, your strength plateaus, and your recovery takes longer than it used to.
But this isn’t your fault — it’s biology. Around the age of 40, your muscles become less responsive to protein intake. Standard protein alone is no longer enough to build or preserve muscle effectively.
The solution?
A small but powerful part of protein: L-leucine — the amino acid that actually triggers muscle growth.
Leucine is an essential amino acid and one of the three branched-chain amino acids (BCAAs).
Its special role: Leucine activates the mTOR pathway — the biological “on switch” for muscle protein synthesis (MPS).
In simple terms:
Without enough leucine, your protein shake won’t kickstart the muscle-building process.
It’s not just the amount of protein that matters — it’s whether your muscles receive enough leucine to respond.
Most protein shakes contain around 20–25 g of protein — which used to be enough.
But as we age, muscle response to protein declines. This is called anabolic resistance.
Studies show:
To trigger the same muscle protein synthesis, older adults need more leucine per meal.
Age Group | Required Leucine for max MPS |
Under 30 | ~2.0 g |
Age 40+ | ≥3.0 g |
Optimal dose | 5.0 g |
Even high-quality whey protein products typically provide only 1.8 to 2.5 g of leucine per serving — far below what’s optimal after 40.
Protein Type | Leucine per 25 g protein |
Standard whey | 2.2 g |
Pea protein | 1.9 g |
Soy protein | 1.8 g |
NoDoubt SilverGreen | 5.0 g |
Only NoDoubt SilverGreen delivers the full 5 g of leucine per serving, as recommended by current scientific research for optimal muscle development in aging athletes.
With age, muscles become less sensitive to protein — a process called anabolic resistance.
While 25–30 g of protein with 2.5–2.8 g leucine per meal is the minimum to activate muscle growth,
current studies show this often isn’t enough to achieve optimal results.
Expert groups such as the PROT-AGE Study Group now recommend up to 5 g leucine per meal, especially in cases of age-related muscle loss (sarcopenia).
This dosage:
Minimum recommendations (2.8 g) might trigger MPS — but for maximum strength, mass, and recovery, 5 g per meal is ideal.
This amount equals:
💡 Or use NoDoubt SilverGreen: 25 g fast-absorbing protein + 5 g pure leucine — scientifically dosed for proven effect, with no guesswork.
When carbs are low — like during heavy workouts or low-carb dieting — your body can convert leucine into ketone bodies.
These serve as alternative fuel for your muscles and brain — keeping you sharp and powerful even in energy-deficit phases.
NoDoubt SilverGreen is designed specifically for active people over 40 — to support muscle growth, regeneration, and long-term performance.
“I eat enough protein.”
Maybe. But are you getting enough leucine per portion? Without that trigger, muscle growth stalls.
“I use BCAAs — that’s enough.”
Only if they provide at least 5 g of leucine. Most BCAA supplements fall short.
“I can get enough leucine from food.”
Possible, but difficult. To hit 5 g of leucine, you’d need:
NoDoubt SilverGreen delivers exactly that — smartly dosed, scientifically validated, and optimized for your lifestyle.
Discover NoDoubt now.
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