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Amino Acid

Leucine (Mono)

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Leucine (Mono). Pure leucine for mTOR.

How it works. Anabolic trigger.

What the research supports. 1 graded claims. Strongest: Stimulates MPS (moderate).

How much to take. Typical dose: 2.5–5 g.

Side effects and interactions. 1 medication interaction listed. No serious side effects listed at normal doses.

Stacking. Pairs well with Creatine monohydrate, Whey or EAAs.

Common forms. Available as Free-form crystalline powder, Capsules or tablets, Pre-mixed recovery or hydration beverages, Time-release formulations.

Key studies. 8 studies cited. The strongest are listed with links to PubMed.

Community. Experiences from people who have tried Leucine (Mono). Anecdotes are not medical advice.

Leucine (Mono). Pure leucine for mTOR.

Molecular structureC6H13NO2 · 131.17 g/mol

What it is

Pure leucine for mTOR.

Food sources

Dietary protein from animal sources (meat, fish, eggs, dairy) and plant sources (soy, legumes, grains)Free-form amino acid powders and capsulesTargeted pre-workout, recovery, or sleep formulations

Goals

Muscle Growth

How it works

Anabolic trigger.

Pathways

  • Anabolic trigger

Effects

  • +Stimulates MPS supports

What the research supports

Stimulates MPSmoderate

Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.

Typical dose
2.5–5 g
TimingConsistent daily timing recommended; split larger doses if GI tolerance is a concern.
With foodEither with or without food.
Best formMost evidence is based on the free-form crystalline powder form.
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Side effects & interactions

Common side effects

  • Well tolerated

Medication interactions

Prescription medications (general)minor

Always disclose Leucine (Mono) use to your prescriber — additive, antagonistic, or pharmacokinetic interactions are possible.

Check any supplement–medication combination with your pharmacist before starting.

Combines with

Pairs well

  • Creatine monohydrateFoundational support for strength, power, and lean mass.
  • Whey or EAAsProvides amino acid substrate for muscle protein synthesis.

Common forms

  • Free-form crystalline powder
  • Capsules or tablets
  • Pre-mixed recovery or hydration beverages
  • Time-release formulations

Key studies

8 studies cited in total.

PubMed: Leucine (Mono) — Stimulates MPS ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Leucine (Mono) and "Stimulates MPS". Filter by RCT, meta-analysis, or year on the results page.

PubMed: Leucine (Mono) — randomized controlled trial ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Leucine (Mono) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

PubMed: Leucine (Mono) — meta-analysis ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching Leucine (Mono) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

Discussion

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