01Product

L-Isoleucine

At a glance

L-Isoleucine from Zhicheng Bio — supply summary

Zhicheng Bio supplies bulk L-Isoleucine, CAS 73-32-5, shipping from Shanghai, China. This grade is produced to order. Every shipment carries a batch Certificate of Analysis; specification sheet and MSDS are supplied on request. Zhicheng Bio publishes no list price — quotes are issued per quantity and Incoterm by email to zhicheng1@zhicheng-bio.cn.

Supplier: Zhicheng Bio, Shanghai, China
CAS number: 73-32-5
Molecular formula: C6H13NO2
Availability: Made to order
Documents: Batch CoA with every shipment; spec sheet and MSDS on request
Packing: 25 kg cartons or bags, adjustable
PubChem CID: 6306
How to get a price: Email RFQ to zhicheng1@zhicheng-bio.cn — no list price is published

BCAA / EAA In stock

L-Isoleucine

CAS 73-32-5 · C6H13NO2

Bulk L-Isoleucine for B2B manufacturing — supplied against your target specification, with documentation your QA can review before anything ships. Pricing below is indicative; send an RFQ for a firm quote, MOQ and lead time.

$5.91 – $6.62 /kg by order volume · indicative, ex-Shanghai

Indicative range — larger volumes price toward the low end. Ingredient markets move weekly; your firm price is confirmed by quotation, typically within one business day.

Category: BCAA / EAA

Availability: In stock

Packing: 25 kg bags, cartons or drums (standard)

Key supply points

Supplied against your target specification — USP / FCC / JP monograph where applicable
Recent batch COA provided with the quotation, before you commit
Consolidates with other SKUs into one shipment out of Shanghai
Third-party lab verification available pre-shipment on request

Documentation with every batch

COA per batchSpec SheetMSDS / SDSExport docs

Third-party lab verification can be arranged pre-shipment on request. Certificates of origin, non-GMO or allergen statements per destination-market requirements.

Request COA & Quote Use the RFQ form

Shipping & Lead Time

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In stock

Destination region Quantity (kg)

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Sea LCLValue

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Documentation-first

COA per batch, Spec Sheet and MSDS — reviewed by your QA before anything ships.

Ready-stock depth

Multi-tonne inventory on core SKUs, plus 28 actives held in our US warehouse in Los Angeles for domestic delivery.

Certified supply chain

Sourced from audited, certified manufacturers — ISO, HACCP, Halal & Kosher available.

Flexible export

25 kg bags, cartons or drums; FOB / CIF / DDP by lane, sea or air consolidation.

02Identity & properties

Identity & properties

Compound identifiers and physical properties for this material. The binding version is always the Specification Sheet and batch COA issued with your quotation.

CAS No.	73-32-5
Molecular Formula	C6H13NO2
Molecular Weight	131.17
EINECS	200-798-2
Synonyms	L-Isoleucine, L-Ile, I, (2S,3S)-2-amino-3-methylpentanoic acid
Appearance	White to off-white crystalline powder; waxy, shiny rhombic leaflets when crystallised from alcohol
Solubility	Water 41.2 g/L at 25 °C (Merck series: 37.9 g/L at 0 °C, 41.2 at 25 °C, 48.2 at 50 °C, 60.8 at 75 °C, 82.6 at 100 °C; Yalkowsky reports 34.4 g/L at 25 °C). Sparingly soluble in hot alcohol (0.13% w/w at 80 °C) and hot acetic acid; insoluble in ether.
Pharmacopoeial reference	FCC · JP

03Specifications

Specifications

Typical parameters below — the binding version is the Specification Sheet and batch COA we send with your quotation.

Parameter	Specification	Test method
Assay (as-is / dried basis)	—	Titration or HPLC per the applicable monograph
Appearance	—	Visual
Identification	—	IR / specific optical rotation per monograph
Specific optical rotation	—	Polarimetry
Loss on drying	—	Gravimetric
Residue on ignition / sulphated ash	—	Gravimetric
Chloride	—	Per monograph
Sulphate	—	Per monograph
Iron	—	Per monograph
Other amino acids / related substances	—	TLC or HPLC per monograph
Heavy metals (Pb / As / Cd / Hg)	—	ICP-MS or per monograph
Microbiology (TAMC / TYMC / E. coli / Salmonella)	—	USP <61>/<62> or equivalent

A dash means we have no fixed limit to publish for that parameter: it is reported on the batch COA and the limit is agreed with your QA. We would rather leave it blank than invent a number. Full physical, chemical, heavy-metal and microbiological parameters are listed in the Specification Sheet — sent with every quotation.

04Formulation & handling notes

Formulation & handling notes

The practical points our technical team raises with buyers of this material — the things that decide whether a batch behaves in your process.

Isoleucine is the middle child of the BCAA trio on solubility and it decides the character of a BCAA beverage. In water at 25 °C: isoleucine 41.2 g/L, valine 88.5 g/L, leucine 24.3 g/L (Merck values). In a 2:1:1 leucine-heavy blend, leucine hits its ceiling first, but isoleucine is what limits you next.

It is distinctly bitter — the Merck Index lists the taste as bitter — and unlike leucine it does not bring a compensating mouthfeel. Bitterness masking in an unflavoured BCAA is largely an isoleucine and leucine problem.

Its solubility climbs steeply with temperature (37.9 g/L at 0 °C to 82.6 g/L at 100 °C), so a hot-fill or warm-mix step buys you real headroom — but the same curve means a cold-chain product can precipitate.

Practically insoluble in organic solvents (0.13% w/w in hot alcohol at 80 °C, insoluble in ether), so it is an aqueous and dry-blend ingredient only.

Isoleucine and leucine share the molecular formula C6H13NO2 and the molecular weight 131.17 — they are structural isomers. That means formula and MW alone cannot distinguish them on a document; the identity test that matters is specific optical rotation (isoleucine is reported at +40.6° at 20 °C, c = 4.6 in 6.1 N HCl) or a chromatographic method. Insist on one of those on the COA.

05Applications

Applications

B2B manufacturing use only — no finished-product or health claims.

BCAA 2:1:1 and 4:1:1 blends

EAA and free-form amino acid powders

Intra-workout beverages

Clinical and enteral nutrition

Capsules and tablets

06Regulatory status by market

Regulatory status by market

Status of the raw material, stated as conservatively as our sources allow. This is supply-chain information, not regulatory advice — confirm the position for your finished product and destination market with your own regulatory counsel.

Market	Status	Basis
United States	Listed by name in FDA's food-additive regulation for amino acids as 'L-Isoleucine'. That regulation permits use as a nutrient 'to significantly improve the biological quality of the total protein' of a food, subject to a cap of 6.6 percent by weight of the total protein of the finished food, and to the labelling requirements in paragraph (e). It is not a general-purpose clearance for any food use, and it is not the authority under which dietary supplements are marketed — those sit under DSHEA and 21 CFR part 111.	21 CFR 172.320(a), (b), (c)(4), (e)
European Union	Amino acids are not covered by the harmonised positive lists of Directive 2002/46/EC (Annexes I and II of that Directive cover vitamins and minerals only). Amino acid ingredients are therefore governed by general EU food law plus national rules, with mutual recognition under Article 4 of Regulation (EC) No 764/2008 in practice.	Directive 2002/46/EC (food supplements); national member-state rules
Japan	An Official Monograph titled 'L-Isoleucine' is listed in the Japanese Pharmacopoeia, Eighteenth Edition. Monograph existence only — no limits transcribed.	JP XVIII, Official Monographs
China	Status as a nutrient fortification substance / food additive under Chinese national standards to be confirmed.	GB 14880-2012 (nutrient fortification substances), GB 2760 (food additives), and NHC new-food-ingredient announcements

07Selected research

Selected research

Peer-reviewed literature on this compound, with linked identifiers so you can read the primary source rather than take our word for it.

These references are listed for scientific context only. They describe published research on the compound; they are not claims about this raw material and not claims about any finished product. Zhicheng Bio makes no medical, health or performance claims.

In rats, a single oral dose of isoleucine (0.3 g/kg) significantly reduced plasma glucose at 30 and 60 minutes after a glucose bolus whereas leucine and valine did not, and 1 mM isoleucine increased glucose consumption in C2C12 myotubes by 16.8% in the absence of insulin. Doi M, Yamaoka I, Fukunaga T, Nakayama M. Biochem Biophys Res Commun. 2003;312(4):1111-1117. PMID 14651987 DOI 10.1016/j.bbrc.2003.11.039 Source
In fasted rats, oral isoleucine decreased plasma glucose by 20% and increased muscle glucose uptake by 71% without a significant rise in plasma insulin, and inhibited glucose production from alanine in isolated hepatocytes. Doi M, Yamaoka I, Nakayama M, Sugahara K, Yoshizawa F. Am J Physiol Endocrinol Metab. 2007;292(6):E1683-E1693. PMID 17299083 DOI 10.1152/ajpendo.00609.2006 Source
A systematic review of oral branched-chain amino acid supplementation in athletes assessed the available trials and reported that the evidence base among athletic populations is not clear-cut. Martinho DV, Nobari H, Faria A, Field A, Duarte D, Sarmento H. Nutrients. 2022;14(19):4002. PMID 36235655 DOI 10.3390/nu14194002 Source

08Packing, storage & lead time

Packing, storage & lead time

Standard packing	25 kg bags, cartons or drums
Private packing	Custom packing & labeling available for regular customers
Storage	Cool, dry place, sealed in original packaging
Lead time	In stock
Shipping	Sea or air consolidation out of Shanghai · FOB / CIF / DDP by lane

09Procurement FAQ

Procurement FAQ

01How do I prove a lot is isoleucine and not leucine?

Not from the formula or molecular weight — they are identical (C6H13NO2, 131.17). Ask for specific optical rotation or a chromatographic identity on the COA. Isoleucine is reported at about +40.6° at 20 °C, c = 4.6 in 6.1 N HCl. This is a real risk on cheap BCAA offers and worth checking on first shipment.

02What is the practical solubility limit for a BCAA drink?

Isoleucine is 41.2 g/L in water at 25 °C. In a 2:1:1 blend leucine (24.3 g/L) caps you first and isoleucine second. Warm mixing helps materially — isoleucine roughly doubles to 82.6 g/L at 100 °C — but you have to design for the coldest temperature the finished product will see.

03Is your isoleucine fermentation-derived or hair-hydrolysate?

Ask and we will get it in writing. Origin matters for vegan, kosher and halal claims and for some destination markets. We source from audited manufacturers and can supply an origin/non-animal declaration where the manufacturer issues one.

04Stock and lead time on this SKU?

This is a small ready-stock item (about 75 kg on hand). Larger quantities are procured to order, typically about one week to Shanghai — worth consolidating with leucine and valine into one shipment.

05What is the MOQ for L-Isoleucine?

MOQ is quote-based and flexible. Tell us your target quantity in the RFQ — for core in-stock SKUs we can usually accommodate both trial orders and multi-tonne volumes.

06Can I get a sample of L-Isoleucine before ordering?

Yes — samples are available on request for evaluation and lab verification. Mention it in your RFQ and we will confirm the arrangement.

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