CAS 61-90-5

L-Leucine

L-Leucine is an essential branched-chain α-amino acid with the formula C₆H₁₃NO₂ and a molar mass of 131.17 g/mol. Its hydrophobic isobutyl side chain places it among the most non-polar of the proteinogenic amino acids and gives it a central role in protein folding and membrane anchoring.

The white crystalline powder is sparingly soluble in cold water and faintly bitter. It is the most actively researched of the three branched-chain amino acids because of its direct stimulatory effect on muscle protein synthesis through the mTOR pathway.

We source bulk L-Leucine from top China manufacturers for our partners, working with several of them. The manufacturers are mostly in Hebei, Jiangsu and Anhui. For this ingredient the minimum order is 500 kg and a 20-foot container takes 20 MT, and a smaller requirement can ship in a combined container with other ingredients.

Please send the grade you need, the volume and your destination port, and we will come back with a solution and a price.

or call +86-21-6858 0751

Minimum order: 500 kg
Qty in 20' FCL: 20 MT
Packaging: 25 kg kraft paper bag with PE inner liner

ISO 9001
HACCP
Halal
Kosher

Specifications

Item	Specification
Appearance	White crystalline powder or granules
Assay (dried basis)	98.5-101.5%
Specific Rotation [α]D20	+14.5° to +16.5° (c=4, 6 mol/L HCl)
Loss on Drying	≤ 0.3%
Residue on Ignition	≤ 0.1%
pH (1% solution)	5.5-7.0
Chloride (as Cl)	≤ 0.02%
Sulfate (as SO₄)	≤ 0.02%
Iron	≤ 10 mg/kg
Other Amino Acids (TLC)	Conforms
Heavy Metals (as Pb)	≤ 10 mg/kg
Lead	≤ 1 mg/kg
Arsenic	≤ 1 mg/kg
Total Plate Count	≤ 1000 CFU/g
Salmonella	Negative/25g

Common Markets Grades

The trade divides L-Leucine into food, supplement, pharmaceutical, and feed grades.

Food and supplement grade L-leucine meets the FCC monograph at 98.5 to 101.5 percent assay on the dried basis. Particle size and bulk density are controlled to suit dry-blend sports nutrition formats, ready-to-mix beverage powders, and clinical-nutrition stick packs.

Pharmaceutical grade L-leucine conforms to USP, Ph. Eur., and JP monographs and is used in parenteral nutrition admixtures, oral amino-acid preparations, and as a glidant in dry-powder inhaler formulations.

Cell-culture and biochemical grades are produced with low endotoxin counts and verified absence of contaminating amino acids. Feed grade L-leucine is graded at lower assay specifications for inclusion in specialty livestock and aquaculture diets.

Applications

Sports nutrition: ratio-balanced BCAA powders, intra-workout drinks, and recovery shakes
Free-leucine fortification of pre- and post-workout formulas for muscle protein synthesis support
Component of parenteral nutrition admixtures for surgical recovery and trauma
Oral nutrition products for sarcopenia, post-operative recovery, and elderly care
Nutritional fortification of infant formula and clinical-nutrition products
Glidant in dry-powder inhaler formulations of inhaled small-molecule drugs
Substrate for the synthesis of HMB (β-hydroxy β-methylbutyrate) in fermentation-based plants
Cell-culture and fermentation media for biopharmaceutical manufacture
Building block in peptide synthesis and pharmaceutical chiral intermediate chemistry
Cosmetic skin-conditioning agent in serums and amino-acid blend lotions
Animal feed supplement in piglet and aquaculture diets

Brands Using L-Leucine

Widely-distributed consumer products that list L-Leucine on the ingredient label.

Brand names, product names and logos are the property of their owners. They appear here as published evidence that the ingredient is used, taken from the brand's own label or website. Their appearance is not an endorsement, and it does not mean the brand buys from us or from any manufacturer listed on this site.

China Manufacturers of L-Leucine

Top L-Leucine manufacturers in China.

Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.

How We Help Source L-Leucine

Direct Factory Sourcing
We run the whole process: selecting the manufacturer from the top Chinese food ingredient producers, negotiating the price, verifying quality, and coordinating the logistics. You deal with us instead of with several factories at once.
Original Packaging and Documents from the Manufacturer
The manufacturer sends your L-Leucine out of its own factory in the original packing, through to your destination port. The COA, COO, MSDS, TDS and any certifications reach you from the manufacturer as well.
Free Samples and Lead Time
We send 100 to 500 g free for your own laboratory to test and you cover only the courier, usually within 2 to 3 working days. ETD is usually within 7 to 15 days once the order is confirmed, and we check that date against the factory's own manufacturing schedule before we give it to you.
Combined Shipment
We can load L-Leucine together with other ingredients such as Glycine, L-Arginine and DL-Methionine into one 20' FCL. If your quantity is small, we can also ship LCL.

Regulatory Status

L-Leucine is broadly accepted as a food ingredient, dietary supplement, and pharmaceutical ingredient.

In the United States it is recognised as a nutrient and dietary supplement, and several independent GRAS notices cover its use in conventional foods, sports beverages, and clinical-nutrition products. USP monographs and FDA's inactive ingredient database both cover use as a pharmaceutical excipient.

The European Union permits L-leucine as a nutrient added to foods for particular nutritional uses, infant formula, and food supplements under Regulation (EU) No 609/2013. EFSA has issued scientific opinions on selected branched-chain amino acid health claims, most of which remain unauthorized.

USP, Ph. Eur., JP, and BP monographs are in force. Halal and Kosher certifications are routinely available for fermentation-derived material that uses plant-based feedstocks and non-animal nitrogen sources.

Manufacturing Process

L-Leucine Manufacturing Process

Loading process diagram…

The dominant industrial route is direct fermentation of glucose by engineered Corynebacterium glutamicum strains. The branched-chain amino acid pathway begins at pyruvate, branches to either valine or isoleucine, and ends with three transamination steps that deliver leucine.

Productive strains carry feedback-resistant acetohydroxyacid synthase and isopropylmalate synthase, amplified expression of the leu operon, and knockouts of pathways that drain the same carbon pool to alanine or lactate. Sugar feed rate, dissolved oxygen, and ammonia control are critical because the pathway competes for pyruvate with the cell's own energy metabolism.

Downstream processing is short. Cells are removed by ultrafiltration, the broth is acidified, and the amino acid is captured on cation-exchange resin, eluted with ammonia, decolorised, concentrated, and crystallised from aqueous alcohol. Recrystallisation gives food and pharmaceutical grades.

Hydrolysis of corn-gluten meal and other leucine-rich proteins still supplies a residual share of the global market, but fermentation now dominates by a wide margin. Pure chemical synthesis is not competitive.