SYS ONLINE
SUPPLEMENT_SCHOLAR
evidence · mechanism · dose
Supplements/Amino Acid

BCAAs

aka Leucine + Isoleucine + Valine

Branched-chain amino acids — leucine is the primary mTOR signal for muscle protein synthesis.

Muscle GrowthAthletic PerformanceRecovery Optimization

Overview

Branched-chain amino acids — leucine is the primary mTOR signal for muscle protein synthesis.

Natural sources
  • Whey
  • Meat
  • Eggs
  • Dairy
Common forms
  • BCAA powder
  • EAA blends (preferred)

Mechanism of action

Leucine activates mTORC1 via Sestrin/GATOR; supplies substrate for muscle protein synthesis.

Pathways
  • · mTORC1 signaling

Effects on the body

Supports
Muscle protein synthesis
Decreases
DOMS (limited)

Organ system effects

Skeletal Muscle

Drive translation initiation.

Evidence-based benefits

Stimulates MPS (less than whole protein/EAAs)

Moderate evidence

Reduces DOMS modestly

Limited evidence

Potential side effects

Common
    Rare
      Serious

        Drug interactions

        Levodopa
        Competes for BBB transport.
        moderate

        Supplement interactions

        Pairs well with
        • Whole protein / EAAs
          EAAs are superior; BCAAs alone are incomplete.
        Avoid combining with

        No specific avoidances listed.

        Dosing & bioavailability

        Typical dose
        5–10 g (2:1:1 ratio); 3 g leucine ≥ threshold for MPS

        Where to buy

        Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

        Amino Acid
        BCAAs
        Amazon
        Wide selection · fast shipping
        Amino Acid
        BCAAs
        iHerb
        Global delivery · curated brands
        Amino Acid
        BCAAs
        Thorne
        Practitioner-grade · NSF tested

        Scientific evidence (9)

        Systematic reviewExamine.com Supplement Database · 2023

        BCAAs: pharmacology, clinical evidence, and safety — narrative review

        Examine.com Research Team

        Curated narrative review of human and preclinical evidence for BCAAs, including mechanism, typical dosing, and safety considerations.

        Key findings

        Best-supported outcome: Stimulates MPS (less than whole protein/EAAs) (evidence: moderate). Additional outcomes and limitations summarized in the full profile.

        Open study
        Systematic reviewPubMed (NLM) · 1970

        PubMed: BCAAs — Stimulates MPS

        Live PubMed search

        Live results for "BCAAs Stimulates MPS" across the PubMed/MEDLINE peer-reviewed index.

        Key findings

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

        Open study
        Systematic reviewPubMed (NLM) · 1970

        PubMed: BCAAs — Reduces DOMS modestly

        Live PubMed search

        Live results for "BCAAs Reduces DOMS modestly" across the PubMed/MEDLINE peer-reviewed index.

        Key findings

        Opens current human and preclinical literature matching BCAAs and "Reduces DOMS modestly". Filter by RCT, meta-analysis, or year on the results page.

        Open study
        Systematic reviewPubMed (NLM) · 1970

        PubMed: BCAAs — randomized controlled trial

        Live PubMed search

        Live results for "BCAAs randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

        Key findings

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

        Open study
        Systematic reviewPubMed (NLM) · 1970

        PubMed: BCAAs — meta-analysis

        Live PubMed search

        Live results for "BCAAs meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

        Key findings

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

        Open study
        Systematic reviewPubMed (NLM) · 1970

        PubMed: BCAAs — pharmacokinetics

        Live PubMed search

        Live results for "BCAAs pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

        Key findings

        Opens current human and preclinical literature matching BCAAs and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

        Open study
        Systematic reviewPubMed (NLM) · 1970

        PubMed: BCAAs — safety adverse events

        Live PubMed search

        Live results for "BCAAs safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

        Key findings

        Opens current human and preclinical literature matching BCAAs and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

        Open study
        Systematic reviewPubMed (NLM) · 1970

        PubMed: BCAAs — dose response

        Live PubMed search

        Live results for "BCAAs dose response" across the PubMed/MEDLINE peer-reviewed index.

        Key findings

        Opens current human and preclinical literature matching BCAAs and "dose response". Filter by RCT, meta-analysis, or year on the results page.

        Open study
        Systematic reviewGoogle Scholar · 1970

        Google Scholar: BCAAs — clinical evidence

        Live Scholar search

        Cross-database citation index for BCAAs as it relates to "clinical evidence".

        Key findings

        Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

        Open study
        Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.