BCAA, Branched-Chain Amino Acid, L-Leucine, L-Isoleucine, L-Valine, 61-90-5, 73-32-5, 72-18-4

BCAA, Branched-Chain Amino Acid, L-Leucine, L-Isoleucine, L-Valine, 61-90-5, 73-32-5, 72-18-4

Definition

BCAAs are a group of three essential amino acids: Leucine, Isoleucine, and Valine. They are called “branched-chain” because of their unique molecular structure. Since the human body cannot synthesize them, they must be obtained from diet or supplements.

Biological Roles

1. Protein Synthesis

   • Leucine is the most potent stimulator of the mTOR pathway, which triggers muscle protein synthesis.

   • This makes BCAAs critical for muscle growth and repair.

2. Energy Supply

   • During prolonged exercise, BCAAs can be oxidized directly in muscle tissue to provide energy.

   • They act as an alternative fuel source when glycogen stores are depleted.

3. Muscle Breakdown Prevention

   • Isoleucine and valine help reduce muscle protein degradation.

   • This supports faster recovery and less soreness after training.

4. Central Fatigue Reduction

   • BCAAs compete with tryptophan for transport into the brain.

   • This can reduce serotonin production, delaying the onset of central fatigue during exercise.

Natural Sources

• Meat, poultry, fish

• Eggs

• Dairy products

• Legumes

Physical and Chemical Properties

• Form: Available as powders, capsules, or ready-to-drink supplements.

• Taste: Naturally bitter, often masked with flavoring in commercial products.

• Solubility: Water-soluble, making them easy to use in sports drinks.

BCAAs (Branched-chain amino acids) product overview

Definition and scope

BCAAs are a group of three essential amino acids with branched aliphatic side chains: leucine, isoleucine, and valine. They are supplied as individual L-amino acids or premixed blends for supplements, most commonly in ratios like 2:1:1 (leucine:isoleucine:valine).

Chemical identity and CAS numbers

Component summary table

Synonyms and other names

Leucine

• Synonyms: L-Leucine, 2-Amino-4-methylpentanoic acid, Leu

• Abbreviations: Leu, L

• Enantiomer notes: Typically supplied as the L-isomer for nutritional use

Isoleucine

• Synonyms: L-Isoleucine, 2-Amino-3-methylpentanoic acid, Ile

• Abbreviations: Ile, I

• Enantiomer notes: Nutritional products use the L-isomer

Valine

• Synonyms: L-Valine, 2-Amino-3-methylbutanoic acid, Val

• Abbreviations: Val, V

• Enantiomer notes: Nutritional products use the L-isomer

Mixtures and market naming

• Common blend names: BCAA powder, BCAA capsules, BCAA 2:1:1, BCAA 4:1:1, BCAA 8:1:1

• Functional claims naming: “Instant BCAA,” “Fermented BCAA,” “Vegan BCAA” (process descriptors, not chemical differences)

Typical contents of BCAA products

Core actives

• Free-form amino acids: L-leucine, L-isoleucine, L-valine in stated ratios (most commonly 2:1:1; higher-leucine formulas exist like 4:1:1 and 8:1:1)

• Purity range: Often 98–100% on dry basis for each amino acid in raw material; finished products include excipients

Functional excipients (powders)

• Flow/instantization aids: Sunflower or soy lecithin for instant mixing

• Carriers/sweeteners: Maltodextrin, dextrose, sucralose, acesulfame-K, stevia (to mask natural bitterness)

• Acidulants and flavors: Citric acid, malic acid; natural/artificial flavors

• Anti-caking agents: Silicon dioxide, calcium silicate

Capsules/tablets

• Capsules: Gelatin or HPMC (vegan) shells; may include magnesium stearate, microcrystalline cellulose

• Tablets: Binders and disintegrants such as MCC, starch, croscarmellose sodium

Labeling and disclosure

• Ratio declaration: Leucine:isoleucine:valine ratio (e.g., 2:1:1)

• Per-serving amounts: mg or g of each amino acid and total BCAA

• Origin/process: “Fermented” indicates microbial fermentation manufacturing of amino acids

Technical and usage details

Physical and chemical properties

• Appearance: White to off-white crystalline powders

• Taste: Intrinsically bitter (especially leucine); masking needed in flavored products

• Solubility: Water dispersible; instantized grades improve wetting and dispersion

Nutritional role

• Protein synthesis: Leucine serves as a primary trigger (mTOR pathway)

• Energy metabolism: Oxidized in muscle during prolonged activity

• Recovery support: Helps reduce protein breakdown post-exercise

Common formulations

• Standalone BCAA: 2:1:1 flavored powder; 5–10 g per serving

• Stacked formulas: Combined with electrolytes, glutamine, citrulline malate, or EAA blends

• Capsules: 500–1000 mg per capsule, multi-capsule servings

BCAA – Sectoral Suitability Table

Summary

BCAAs are most strongly positioned in the sports nutrition sector, where they are considered essential for athletes and bodybuilders. They also have secondary applications in functional foods and ongoing research in pharmaceuticals and cosmetics, but their commercial strength lies in supplements designed for muscle growth, recovery, and endurance.