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PERFORMANCE & RECOVERY

BCAAs (2:1:1 Leucine ratio)

Intra-workout · muscle preservation

MODERATE EVIDENCEVEGANREAD THE RESEARCH
Written to our editorial standards · reviewed against published research· Updated 2 Jun 2026
Last reviewed: May 30, 2026
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BCAAs: Intra-workout · muscle preservation. Branched-chain amino acids, leucine, isoleucine, valine, that preserve muscle during fasted or long training sessions. Standard dose 7 g, taken in the pre-workout, about $28/month. Evidence rating: moderate evidence.

What is BCAAs?

Branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, are three of the nine essential amino acids and the only ones metabolized primarily in skeletal muscle rather than the liver. Leucine is the primary trigger of muscle protein synthesis via the mTOR pathway. BCAA supplementation is most valuable in specific contexts: during fasted training, long endurance sessions, or for individuals struggling to consume adequate total protein. For people already meeting protein targets (around 1.6 g/kg/day), adding whey or a complete protein source is generally more effective than isolated BCAAs. The standard 2:1:1 leucine ratio at 5-10 g per serving is the most-studied dose.

WHY IT MATTERS

Branched-chain amino acids, leucine, isoleucine, valine, that preserve muscle during fasted or long training sessions.

Natural food sources

Where possible, get BCAAs from whole foods first. Common dietary sources include:

Chicken & beefEggsWhey & dairySoybeansLentils

Where to buy

Scivation Xtend BCAA Unflavored
RECOMMENDED
Scivation Xtend, BCAAs
7 g · Pre-workout · ~$28/month

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Common questions

What is BCAAs?
Branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, are three of the nine essential amino acids and the only ones metabolized primarily in skeletal muscle rather than the liver. Leucine is the primary trigger of muscle protein synthesis via the mTOR pathway. BCAA supplementation is most valuable in specific contexts: during fasted training, long endurance sessions, or for individuals struggling to consume adequate total protein. For people already meeting protein targets (around 1.6 g/kg/day), adding whey or a complete protein source is generally more effective than isolated BCAAs. The standard 2:1:1 leucine ratio at 5-10 g per serving is the most-studied dose.
What is BCAAs used for?
Intra-workout · muscle preservation. Branched-chain amino acids, leucine, isoleucine, valine, that preserve muscle during fasted or long training sessions.
What is the standard dose of BCAAs?
7 g, typically taken in the pre-workout. Approximate cost is $28 per month.
How strong is the evidence for BCAAs?
Moderate evidence for its primary uses. See the full study list on the research page.

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