BCAAs
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BCAAs. Branched-chain amino acids — leucine is the primary mTOR signal for muscle protein synthesis.
How it works. Leucine activates mTORC1 via Sestrin/GATOR; supplies substrate for muscle protein synthesis.
What the research supports. 2 graded claims. Strongest: Stimulates MPS (less than whole protein/EAAs) (moderate).
How much to take. Typical dose: 5–10 g (2:1:1 ratio); 3 g leucine ≥ threshold for MPS.
Side effects and interactions. 1 medication interaction listed. Serious: Discontinue and seek medical advice if symptoms are severe, persistent, or include difficulty breathing.
Stacking. Pairs well with Whole protein / EAAs.
Common forms. Available as BCAA powder, EAA blends (preferred).
Key studies. 9 studies cited. The strongest are listed with links to PubMed.
Community. Experiences from people who have tried BCAAs. Anecdotes are not medical advice.
BCAAs. Branched-chain amino acids — leucine is the primary mTOR signal for muscle protein synthesis.
What it is
Branched-chain amino acids — leucine is the primary mTOR signal for muscle protein synthesis.
Also called
Food sources
Goals
How it works
Leucine activates mTORC1 via Sestrin/GATOR; supplies substrate for muscle protein synthesis.
Pathways
- mTORC1 signaling
Effects
- +Muscle protein synthesis supports
- ↓DOMS (limited) decreases
What the research supports
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.
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Side effects & interactions
Common side effects
- BCAAs is generally well-tolerated at evidence-based doses
- Mild GI discomfort (nausea, loose stools, or bloating) possible at higher intakes
- Headache or transient fatigue reported by a small fraction of users
Serious
- Discontinue and seek medical advice if symptoms are severe, persistent, or include difficulty breathing
Medication interactions
Competes for BBB transport.
Check any supplement–medication combination with your pharmacist before starting.
Combines with
Pairs well
- Whole protein / EAAsEAAs are superior; BCAAs alone are incomplete.
Common forms
- BCAA powder
- EAA blends (preferred)
Key studies
9 studies cited in total.
Opens current human and preclinical literature matching BCAAs and "Stimulates MPS". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching BCAAs and "Reduces DOMS modestly". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching BCAAs and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.
Discussion
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