L-Carnitine calculator
A naturally occurring compound involved in fat transport into mitochondria, available as an oral supplement and an injectable prescription product.
Also known as: Carnitine, Levocarnitine
FDA status — not an approved drug Levocarnitine is FDA-approved as a prescription drug for carnitine deficiency. Over-the-counter L-carnitine sold for weight loss is a dietary supplement and is not FDA-approved to treat any condition.
This draw does not fit the selected syringe.1000 units exceeds the 100-unit barrel. Choose a larger syringe, use less bacteriostatic water, or split the dose.
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What L-Carnitine is
L-carnitine is a compound the body makes to shuttle fatty acids into mitochondria, where they are burned for energy. It is sold as an oral supplement and, as levocarnitine, is an FDA-approved prescription treatment for carnitine deficiency. Its use for general weight loss is far less supported.
Research depth: 4/5 Extensive study as a nutrient and an approved deficiency treatment; weight-loss efficacy in non-deficient people is weak. Human trials: Large literature, mixed efficacy. This measures how much has been studied — counting animal and laboratory work — not whether it works for you.
How L-Carnitine works
Carnitine forms a shuttle that carries long-chain fatty acids across the mitochondrial membrane so they can be oxidized. Supplementing raises carnitine levels, but in people who are not deficient this has not reliably translated into clinically meaningful fat loss in controlled trials.
L-Carnitine side effects
Commonly reported
- Nausea, stomach upset, and diarrhea
- Fishy body odor at high doses
- Injection-site discomfort with the injectable form
Serious — seek medical care
- Seizures reported in people with seizure disorders
- Possible increase in TMAO, a cardiovascular risk marker under study
- Generally well tolerated at typical supplemental doses
This list is not exhaustive. Report anything unexpected to the clinician who prescribed it. If you have severe abdominal pain, trouble breathing, or signs of an allergic reaction, seek care the same day. See also our guide to peptide side effects by class.
A worked example
A 500 mg vial reconstituted with 5 mL of bacteriostatic water gives 100 mg/mL. A 1000000 mcg dose is then 10 mL — about 1000 units on a 100-unit insulin syringe, giving roughly 0 doses per vial before accounting for residual volume left in the vial and syringe.
Prefer paper? Download the printable L-Carnitine dosing chart (PDF) — every vial size and water volume in syringe units, with the same review byline as this page. All charts →
Commonly cited dose range
Figures circulating for L-Carnitine run from 500000 mcg to 2000000 mcg. Amounts discussed are in the hundreds to thousands of milligrams. Shown in micrograms for calculator consistency — 1,000,000 mcg is 1,000 mg. For the prescription product, follow its labeling.
Read this as reference information, not instruction. These numbers describe what is commonly discussed, not what is right for any individual. Dose, frequency, and whether to use L-Carnitine at all are decisions for a licensed clinician who knows your history.
Common questions
Does L-carnitine work for weight loss?
Evidence for meaningful weight loss in people without a deficiency is weak and inconsistent. It is well established for treating true carnitine deficiency, which is a different use.
Is L-carnitine a peptide?
No. L-carnitine is an amino-acid-derived nutrient, not a peptide. It appears here because it is sold alongside peptide products.