L-carnitine
L-carnitine suppliers and sourcing guide
L-carnitine is a small quaternary ammonium compound found mainly in meat and dairy foods. Commercial L-carnitine is made by chemical synthesis followed by separation of the L-form, or by microbial biotransformation, then purified and crystallized. The free base absorbs moisture very readily, so brands often buy stabilized salts such as L-carnitine L-tartrate or fumarate for tablets and capsules, and the base or a liquid solution for drinks.
- Category
- Proteins and amino acids
- Also known as
- Levocarnitine · Carnitine · Vitamin BT
- Facts checked
- November 2026
Forms and grades of L-carnitine
Suppliers sell different products under the same name. Specify the one you need.
L-carnitine base
Crystalline inner salt, very hygroscopic, used mainly in liquids, drink mixes and soft products.
L-carnitine L-tartrate
A less hygroscopic salt with tartaric acid, sold as a separate ingredient for tablets, capsules and powders.
L-carnitine fumarate
A salt with fumaric acid, used in tablets and capsules.
Liquid solution
L-carnitine dissolved in water at a stated concentration, for drink manufacturing.
Granulated grades
Base or salts granulated or blended with a flow agent for tableting and capsule filling.
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 L-carnitine.
- Assay
- Purity on a dried basis by nonaqueous titration or HPLC, reported against the USP, FCC or supplier specification.
- Related substances
- Enantiomeric purity (D-carnitine) by chiral HPLC, plus related substances 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.
Storage, lots and expiry
Storage and shelf life
L-carnitine base is strongly hygroscopic and will liquefy if left open, so keep it in tightly sealed, lined containers with desiccant in a cool, dry room and reseal immediately after use. Salts are more forgiving but should be stored the same way. Shelf life or retest date is set by the supplier's specification, with assay and water content as the usual retest points.
Lots and expiry dates
Record assay, water content and enantiomeric purity for each lot, and calculate L-carnitine content from the salt form you buy. Check older lots of base for caking or wet spots before use.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
FDA's Substances Added to Food inventory lists L-carnitine, also called levocarnitine, with the technical effect nutrient supplement.
Source: hfpappexternal.fda.gov (opens in a new tab)Health Canada's L-Carnitine natural health product monograph lists L-carnitine, L-carnitine fumarate and L-carnitine tartrate as source ingredients.
Source: webprod.hc-sc.gc.ca (opens in a new tab)The monograph limits combined L-carnitine and acetylcarnitine to 4 grams per day and 2 grams per single dose.
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-carnitine suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking L-carnitine 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-carnitine? Request a listingFrequently asked questions
What forms of L-carnitine can brands buy?
Common forms include l-carnitine base, l-carnitine L-tartrate, l-carnitine fumarate, liquid solution and granulated grades. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for L-carnitine include?
Expect identity, assay, related substances, loss on drying and residue on ignition and heavy metals and microbiology, each with its method, specification and result for that lot.
How should L-carnitine be stored?
L-carnitine base is strongly hygroscopic and will liquefy if left open, so keep it in tightly sealed, lined containers with desiccant in a cool, dry room and reseal immediately after use. Salts are more forgiving but should be stored the same way. Shelf life or retest date is set by the supplier's specification, with assay and water content as the usual retest points.
What is the regulatory status of L-carnitine?
FDA's Substances Added to Food inventory lists L-carnitine, also called levocarnitine, with the technical effect nutrient supplement. Health Canada's L-Carnitine natural health product monograph lists L-carnitine, L-carnitine fumarate and L-carnitine tartrate as source ingredients. The monograph limits combined L-carnitine and acetylcarnitine to 4 grams per day and 2 grams per single dose.
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- Whey Protein IsolateWPI · whey isolate
- Whey protein concentrateWPC · WPC 80
- Whey protein hydrolysateWPH · hydrolyzed whey protein
- Micellar caseinmicellar casein isolate · casein micelles
- Milk protein concentrateMPC · MPC 70
- Milk protein isolateMPI · milk protein
- Sodium caseinatecasein sodium · caseinate sodium salt
- Calcium caseinatecasein calcium · caseinate calcium salt
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