L-carnitine (levocarnitine) is the (R)-enantiomer of 3-hydroxy-4-(trimethylammonio)butanoate, a small zwitterionic betaine. It is made in the body and obtained from meat and dairy foods, and is also sold as salts such as the L-tartrate.
L-carnitine testing at Vanguard Laboratory: purity, quantity and identity from $250 per sample. Results in 3 to 5 business days; sterility 14 days.
Full USP monograph testing is available (USP monograph: Levocarnitine). See USP Testing.
On this page: Testing · Compound data · Structure and names · Research · Analytical notes · USP–NF · References
Chromatographic purity and mg per unit by the method matched to the compound, identity against a reference standard. 1 unit.
| Add-on test | Price |
|---|---|
| Identity and impurities | |
| FTIR identity | $90 |
| CHNS elemental analysis (carbon, hydrogen, nitrogen, sulfur) | $125 |
| Chiral purity (where a chiral method exists; new methods quoted) | $250 |
| Water, solvents and salt form | |
| Water content by Karl Fischer | $60 |
| Residual solvents | $150 |
| Counterions: chloride, acetate and TFA | $70 |
| Assay | |
| Assay, % w/w (with raw powder purity; $250 together) | +$50 |
| Metals and conformity | |
| Heavy metals: arsenic, cadmium, chromium, mercury and lead | $150 |
| Conformity: purity and quantity on more units from the same lot | $100 per extra unit |
| Microbiology (injectables) | |
| Endotoxin | $210 |
| Sterility or bioburden | $150 |
| Container closure integrity (CCI) | $50 |
| Screening | |
| Fentanyl screen | $50 |
10% off for 10 or more samples.
Need something else? We run other tests on request.
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| Test | Purpose for this compound | Reported as | Sample | Turnaround |
|---|---|---|---|---|
| Purity and quantity | Purity and quantity by HPLC. Impurity peaks are reported; identifying specific impurities, such as crotonobetaine, is a separate request. | Purity, area percent, two decimals. Quantity, mg per unit, with label claim. | 1 sample unit; contact the laboratory about quantity for the submitted format. | 3 to 5 business days from receipt. |
| Identity | Identity by HPLC against a reference standard. Routine HPLC does not distinguish L-carnitine from D-carnitine. | Match or no match, with the basis stated. | No additional sample unit. | 3 to 5 business days, with purity and quantity. |
| Water content | Hygroscopic; the assay is calculated on the anhydrous basis. | Water content, percent w/w. | Sample quantity depends on the requested tests; contact the laboratory before shipping. | 3 to 5 business days from receipt. |
| Counterion | Tartrate and other salts change carnitine content per gram. Counterions are measured by ion chromatography: TFA, acetate and chloride at $70; tartrate, fumarate and other ions are quoted per project. | Counterion content, percent w/w. | Sample quantity depends on the requested tests; contact the laboratory before shipping. | 3 to 5 business days from receipt. |
| Endotoxin | Applies to injectable levocarnitine solutions. | EU per vial, numeric, or below the reporting limit. Reporting limit, dilution and the applicable limit. | Sample quantity depends on the requested tests; contact the laboratory before shipping. | 3 to 5 business days from receipt. |
L-carnitine purity and quantity are measured by HPLC in powders, capsules, injectables and other formats. Testing covers L-carnitine; D-carnitine (enantiomer) testing is not part of the service.
What these results do not show: results describe the sample tested. Purity and content do not establish biological activity, sterility, or the absence of contaminants that were not tested.
L-carnitine: 2D structure drawn from the PubChem record. Stereochemistry shown as registered.
quaternary ammonium betaine (hydroxy acid zwitterion)
C7H15NO3
161.20 g/mol (inner salt, free form)
Monoisotopic 161.1052
541-15-1
Stereochemistry: (R)-configuration at C3; the (S)-enantiomer, D-carnitine, is a specified impurity
CAS note: Levocarnitine inner salt (zwitterion). L-Carnitine L-tartrate is a separate CAS, 36687-82-8 (C18H36N2O12, 472.49).
Other names: Levocarnitine (INN/USAN/USP), L-Carnitine inner salt, (R)-3-Hydroxy-4-(trimethylammonio)butanoate, (-)-Carnitine, Carnitor
PubChem CID 10917 · UNII 0G389FZZ9M[1, 6, 7]
Structural features:
Active ingredient of FDA-approved Carnitor (levocarnitine) tablets, oral solution and injection and their generics[8]; also sold as a dietary supplement ingredient.
Summaries of published research, for reference only. Not a claim of safety or efficacy.
Levocarnitine Tablets[3]
Levocarnitine Oral Solution[4]
Levocarnitine Injection[5]
Levocarnitine Tartrate: proposed (Pharmacopeial Forum), not official.
Vanguard Laboratory:
Related general chapters: 〈85〉 Bacterial Endotoxins Test, 〈71〉 Sterility Tests, 〈788〉 Particulate Matter in Injections, 〈711〉 Dissolution, 〈921〉 Water Determination. General chapters describe test methods; they are not compound-specific monographs. Chapters numbered 1000 to 1999, such as 〈1503〉, are informational.
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