L-Leucine
The primary anabolic trigger among branched-chain amino acids. Directly activates mTOR signaling to initiate muscle protein synthesis. The "leucine threshold" (~2-3g) must be met per meal for maximal MPS stimulation.
Projected serum levels — 3 g (≈ 3k mg), once daily
Maintenance schedule: 3 g (≈ 3k mg) once daily (oral).
Modeled steady state after ~1 days: peak ≈ 2.1k mg, trough ≈ 17.0 mg body load. Population-based estimate over 15 days for a reference dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Amino Acid
- Route modeled
- Oral
- Model confidence
- inferred
- Half-life
- 2 h
- Common dose
- 3 g (≈ 3k mg)
- Suggested maximum
- 12 g/day
- Reference dose range
- 1.5–12 g (single dose)
- Suggested cadence
- once daily
- Validated against
- 3k mg oral — Cmax 85 mg/L at 1 h
Documented interactions
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moderate
EAAs (Essential Amino Acids) + L-Leucine
EAAs (Essential Amino Acids) and L-Leucine both push the endogenous amino acid pool and mtor in the same direction.
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moderate
L-Glutamine + L-Leucine
L-Glutamine and L-Leucine both push the endogenous amino acid pool and mtor in the same direction.
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moderate
Whey Protein Concentrate + L-Leucine
L-Leucine and Whey Protein Concentrate both push the endogenous amino acid pool and mtor in the same direction.
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moderate
Whey Protein Isolate + L-Leucine
L-Leucine and Whey Protein Isolate both push the endogenous amino acid pool and mtor in the same direction.
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watch
Egg White Protein + L-Leucine
Egg White Protein and L-Leucine both push the endogenous amino acid pool in the same direction.
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watch
Glycine + L-Leucine
Glycine and L-Leucine both push the endogenous amino acid pool in the same direction.
Serum checks 12 modeled interaction pairings for l-leucine across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.
Research behind this entry
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Leucine supplementation and intensive training
Review found leucine activates the mTOR pathway to stimulate muscle protein synthesis, with a threshold of approximately 2-3g per feeding needed to maximize the anabolic response.
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Compartmental approach for evaluation of plasma kinetics and (13)co(2)-exhalation after oral loading with L-[1-(13)c]leucine.
This citation reports a human primary study involving L-Leucine. It does not by itself establish a qualified dose, safety profile, efficacy claim, or pharmacokinetic route for this record.
2 published studies referenced in the app, each with a plain-language summary.