L-ornithine
L-ornithine suppliers and sourcing guide
L-ornithine is an amino acid that is not built into proteins and is closely related in structure to arginine and citrulline. Commercial L-ornithine is made by fermentation or by enzymatic hydrolysis of L-arginine, then crystallized, and is usually sold as L-ornithine monohydrochloride. Other forms include L-ornithine L-aspartate and ornithine alpha-ketoglutarate, bought as white powders for capsules, tablets and powder blends.
- Category
- Proteins and amino acids
- Also known as
- Ornithine · L-ornithine hydrochloride · L-ornithine monohydrochloride
- Facts checked
- November 2026
Forms and grades of L-ornithine
Suppliers sell different products under the same name. Specify the one you need.
L-ornithine HCl
The monohydrochloride salt, the most common and stable form.
L-ornithine L-aspartate
A salt of ornithine with aspartic acid, sold as a separate grade.
Ornithine alpha-ketoglutarate
A salt with alpha-ketoglutaric acid, offered by fewer suppliers.
Fermented (plant-sugar) grade
L-ornithine made by bacterial fermentation of corn, cassava or beet sugar; the source and any vegan statement appear on the supplier's spec.
What to check on the COA
Compare each result with your own specification when the lot arrives.
- Identity
- Infrared spectrum matched to a reference standard, plus specific optical rotation, which confirms the L-form of ornithine.
- Assay
- Purity on a dried basis by nonaqueous titration or HPLC, reported against the USP, FCC or supplier specification.
- Related substances
- Other amino acids, especially arginine and citrulline, by HPLC.
- Loss on drying and residue on ignition
- Moisture by loss on drying and inorganic residue as residue on ignition (sulfated ash), with chloride and sulfate where the specification lists them.
- Heavy metals and microbiology
- Lead, arsenic, cadmium and mercury by ICP-MS, plus total plate count, yeast and mold, E. coli and Salmonella.
- Chloride
- Chloride content for the hydrochloride, which confirms the salt form.
Storage, lots and expiry
Storage and shelf life
Store L-ornithine in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Shelf life or retest date is set by the supplier's specification; assay, loss on drying and micro are the usual retest points for older stock.
Lots and expiry dates
Record the salt form and assay for each lot, and calculate ornithine content from the salt. Rotate stock FEFO.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
FDA's Substances Added to Food inventory lists L-ornithine monochlorohydrate (ornithine) with the technical effect flavoring agent or adjuvant.
Source: hfpappexternal.fda.gov (opens in a new tab)The inventory entry cites FEMA No. 4190.
Source: hfpappexternal.fda.gov (opens in a new tab)Health Canada's Workout Supplements monograph lists L-ornithine hydrochloride and L-ornithine-L-aspartate as source ingredients for L-ornithine.
Source: webprod.hc-sc.gc.ca (opens in a new tab)
This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
L-ornithine suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking L-ornithine suppliers now
Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.
Sell L-ornithine? Request a listingFrequently asked questions
What forms of L-ornithine can brands buy?
Common forms include l-ornithine HCl, l-ornithine L-aspartate, ornithine alpha-ketoglutarate and fermented (plant-sugar) grade. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for L-ornithine include?
Expect identity, assay, related substances, loss on drying and residue on ignition, heavy metals and microbiology and chloride, each with its method, specification and result for that lot.
How should L-ornithine be stored?
Store L-ornithine in tightly closed, lined containers in a cool, dry place away from light and strong odors, and reseal opened packs promptly. Shelf life or retest date is set by the supplier's specification; assay, loss on drying and micro are the usual retest points for older stock.
What is the regulatory status of L-ornithine?
FDA's Substances Added to Food inventory lists L-ornithine monochlorohydrate (ornithine) with the technical effect flavoring agent or adjuvant. The inventory entry cites FEMA No. 4190. Health Canada's Workout Supplements monograph lists L-ornithine hydrochloride and L-ornithine-L-aspartate as source ingredients for L-ornithine.
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