Metabolic HealthEvidence-BasedSep 2026

Injectable L-Carnitine: Evidence, Study Doses & Side Effects

Injectable L-carnitine, sold under the pharmaceutical name levocarnitine, is a prescription drug, not a supplement and not a peptide. In the United States it is an approved injection used in clinical and dialysis settings to correct carnitine deficiency, and its label is specific about the two conditions it treats and honest about the limits of what raising carnitine actually changes.¹ Around that narrow medical use sits a different question, L-carnitine injections for fat loss and energy, which has a much thinner answer. This page separates the two: what injectable L-carnitine is, what the US label and the human trials actually show, the doses those studies and the label used, the side effects on record, and what could and could not be verified about its status in Vietnam. It does not tell anyone what to take.

This is general education, not medical advice. Injectable L-carnitine (levocarnitine) is a prescription drug given intravenously in medical settings. Nothing here is a dose recommendation, an administration guide, or a suggestion to inject anything. The dose figures below are quoted from published trials, from animal studies, or from the US label, each one labelled with its source and its evidence level, and none of them is a recommendation for you. Injecting an unapproved product bought outside a regulated supply chain carries real safety risk. Decisions about carnitine belong with a licensed clinician, and in Vietnam you can confirm a product with the Drug Administration of Vietnam.

Rx only

US status (prescription)

Route on the US label

Approved US indications

What injectable L-carnitine is

The injectable form is levocarnitine, the pharmaceutical name for L-carnitine. The US label gives its chemical name as 3-carboxy-2(R)-hydroxy-N,N,N-trimethyl-1-propanaminium, inner salt, with the formula C7H15NO3 and a molecular weight of 161.20.¹ An independent compound record confirms the same identity: PubChem lists CID 10917, formula C7H15NO3, molecular weight 161.20, and the CAS number 541-15-1.² On that structure, a single small molecule of about 161 daltons with a quaternary trimethylammonium group and a hydroxybutanoate backbone, with no amino acid residues and no amide bonds, it reads as a small molecule quaternary ammonium compound rather than a peptide. That is a structural reading of the identity records, not a claim either record makes in those words.

The label calls carnitine a naturally occurring substance required in mammalian energy metabolism, and it describes the mechanism as facilitating the entry of long chain fatty acids into the mitochondria, where they are burned for energy.¹ The reason an injectable version exists at all is absorption: the label reports that the oral formulations had an absolute bioavailability of only 15.1 plus or minus 5.3 percent after correction for the carnitine the body already makes.¹ Injecting the drug bypasses that bottleneck, which is why it is the form reached for in the deficiency states below, and why parenteral carnitine came into use for patients on total parenteral nutrition and for premature infants at risk of deficiency.¹⁰

In the United States it is an approved prescription drug. The originator, CARNITOR levocarnitine injection, sits under application NDA020182 (Leadiant Biosciences) at a strength of 200 mg per mL, and several further injectable applications are approved at the same strength, all with prescription marketing status.³ The presentation is a sterile aqueous solution, 1 g in a 5 mL single dose vial, with no preservative.¹ The year the injectable form was first approved in the United States was not established by the records gathered for this page, so it is not stated here.

At a glance	Detail (from the records)
Pharmaceutical name	Levocarnitine (L-carnitine)
What it is	A small molecule quaternary ammonium compound, not a peptide
Molecular formula and weight	C7H15NO3, molecular weight 161.20
CAS number	541-15-1
US regulatory status	Approved prescription injection, 200 mg per mL
Route on the US label	Intravenous only; no label sentence authorizes IM or SC
Approved US indications	Secondary carnitine deficiency (inborn errors) and carnitine deficiency in dialysis

Identity and status drawn from the US CARNITOR label, the openFDA Drugs@FDA records, and the PubChem compound record.¹²³

What it is approved to treat

The US label lists exactly two approved indications. The first is the acute and chronic treatment of patients with an inborn error of metabolism that results in secondary carnitine deficiency. The second is the prevention and treatment of carnitine deficiency in patients with end stage renal disease who are undergoing dialysis.¹ Both are deficiency states. There is no approved indication in that label for fat loss, body composition, athletic performance, energy, or cosmetic use.¹

The most load bearing sentence in the label: for dialysis patients it states that while the ability of the drug to increase carnitine concentrations has been demonstrated, the effects of supplemental carnitine on the signs and symptoms of carnitine deficiency and on clinical outcomes have not been determined.¹ In other words, the drug reliably raises a blood level; whether that changes how patients feel or do is, by the label's own account, not established.

That the US label has no fat loss or performance indication is a statement about this specific label. It is not a claim about every regulator in the world, because other national registers were not checked for this page. What it does support is a simple, honest framing: using injectable L-carnitine for physique or energy is an off label, unapproved use, and the evidence for those goals is a separate question from the deficiency uses the drug is actually approved for.

What the human evidence shows

The honest summary is mixed and modest. Within the studies gathered for this page, the injectable and infused L-carnitine human evidence is a small set: a few small trials plus one retrospective study, including one clean negative result and one study that used a related but distinct compound. No large clinical outcome trial appears in this set. That describes the studies collected here through a single, capped literature search, not the entire published literature, which is far larger.

A randomized controlled trial in 40 patients scheduled for abdominal surgery found that markers of oxidative stress and platelet activation rose from baseline in the placebo group after surgery and did not differ significantly from baseline in the L-carnitine group.⁴ Those are surrogate laboratory markers from a single pre surgery dose, not a demonstrated clinical outcome. A randomized crossover trial in healthy volunteers went the other way: an L-carnitine infusion did not alleviate lipid induced insulin resistance or metabolic inflexibility, and it did not change carnitine content in skeletal muscle, a clean negative for that metabolic use.⁵

A controlled clinical trial in 18 people with type 2 diabetes reported increased glucose uptake, but it used acetyl-L-carnitine, which is a related yet chemically distinct compound, not L-carnitine, and the effect had no relationship to the amount infused.⁶ In 80 Japanese dialysis outpatients, serum carnitine rose, and hemoglobin improved in the hemodialysis group, over a two phase oral then intravenous regimen, but there was no significant improvement in muscle spasm overall, and the sequential design cannot isolate what the injections alone contributed.⁷ A retrospective study of 44 children with reduced heart function saw ejection fraction improve over a period that included oral or intravenous carnitine, but the abstract states no dose and does not separate the oral and intravenous arms, so no injectable dose or effect can be drawn from it.⁸ Two further records are review articles rather than trials: one on secondary carnitine deficiency,¹⁰ and one arguing that exogenous carnitine is protective against cardiovascular disease, which is a review assertion and not trial data.¹¹

Put together, this is a real but limited picture: a reliable rise in blood carnitine, a scatter of small and mixed functional signals, at least one clean negative, and no large outcome trial in the set. It falls well short of what the fat loss and energy marketing implies.

Study and label doses

Every figure below is reproduced with its source and its evidence level. None of them is a recommendation, and this page will not tell any reader what to take. The human study doses come first, then the doses the US label itself specifies for the conditions it treats.

In the abdominal surgery trial, L-carnitine was given as a single rapid infusion of 0.05 g/kg diluted in 250 mL of saline just before surgery (trial dose, not a recommendation, PMID 21770897).⁴ In the insulin resistance crossover trial, the L-carnitine infusion was 28 mg/kg, co-infused with a lipid emulsion during a clamp (trial dose, not a recommendation, PMID 32976523).⁵ The type 2 diabetes trial used acetyl-L-carnitine, the distinct compound noted above, given intravenously as a 5 mg/kg priming bolus followed by a constant infusion of 0.025, 0.1, or 1.0 mg/kg per minute (trial dose, not a recommendation, PMID 10877193).⁶ The dialysis trial gave oral L-carnitine 600 mg per day to everyone (trial dose, not a recommendation, PMID 33139659) and, to the hemodialysis patients only, intravenous L-carnitine injections of 1000 mg three times weekly (trial dose, not a recommendation, PMID 33139659).⁷ A recommendation paper on carnitine in parenteral nutrition, which is a proposal rather than a trial, suggested nutritional supplementation of 2 to 5 mg/kg per day and pharmacologic supplementation of 50 to 100 mg/kg per day reserved for removing toxic compounds (published recommendation, not a trial, and not a recommendation for you, PMID 19874944).⁹

The US label sets out its own dosing for the deficiency conditions it treats. These are label instructions for specific patients under medical supervision, not a recommendation to anyone. For inborn errors of metabolism, the label states a dose of 50 mg/kg as a slow two to three minute bolus or by infusion, given every three or four hours and never less than every six hours, with subsequent daily doses around 50 mg/kg and the highest dose administered being 300 mg/kg (US label instruction, not a recommendation).¹ For end stage renal disease patients on hemodialysis, the label states a starting dose of 10 to 20 mg/kg of dry body weight as a slow two to three minute bolus into the venous return line after each dialysis session, with a downward adjustment toward about 5 mg/kg possible from the third or fourth week (US label instruction, not a recommendation).¹ The label's monitoring target is a plasma free carnitine concentration of 35 to 60 micromol/L, with plasma carnitine checked before starting and then weekly and monthly (US label instruction, not a recommendation).¹ In the label's pharmacokinetic work, a slow three minute intravenous bolus of 20 mg/kg was used, after which about 76 percent of the dose was excreted in the urine over 0 to 24 hours and the terminal elimination half life averaged 17.4 hours (US label pharmacokinetic figure, not a recommendation).¹

Two things are worth holding onto from this list. First, wherever these human records used an injection, the route was intravenous, an infusion or an injection into a vein, done in a clinical setting, though some of those trials also gave carnitine orally. Second, the numbers vary by more than an order of magnitude depending on the condition being treated, which is exactly why a figure lifted out of a label or a trial tells an individual nothing about what would be appropriate for them. If mixing or dilution is the practical question, the arithmetic of turning a vial into a concentration is covered by the reconstitution calculator, though preparing an intravenous drug is a clinical task, not a home one.

What animal studies used

Several of the injectable carnitine studies in this set were done in animals, and animal results do not establish what happens in people. They also use a route, intraperitoneal injection into the abdominal cavity, that is standard in rodent research and is not how the drug is used in humans. The figures are recorded here for completeness, each with its species and route.

In male Wistar rats, L-carnitine at 300 or 500 mg/kg per day by intraperitoneal injection reduced dexamethasone induced metabolic and liver changes, mainly at the higher dose (animal study, rat, intraperitoneal, PMID 39736705).¹²
In male Wistar rats, L-carnitine at 2.5 g/kg by intraperitoneal injection lowered valproate induced high blood ammonia, and only at the one and a half hour mark (animal study, rat, intraperitoneal, PMID 36741198).¹³
In rats, acetyl-L-carnitine, again the distinct compound, at 50 or 100 mg/kg per day by daily intraperitoneal injection for 14 days improved erectile function after nerve injury (animal study, rat, intraperitoneal, PMID 35420721).¹⁴
In a mouse colitis model, acetyl-L-carnitine by intraperitoneal injection eased several markers of colitis, but the abstract states no dose (animal study, mouse, intraperitoneal, PMID 38369215).¹⁵
In prepubertal rats, L-carnitine injected before and after cisplatin improved sperm measures in adulthood, but the abstract neither names the injection route nor states a dose (animal study, rat, route not stated, PMID 29388451).¹⁶

For scale on toxicity, the label reports an intravenous median lethal dose in rats of 5.4 g/kg and an oral median lethal dose in mice of 19.2 g/kg (label toxicology figures, rat intravenous and mouse oral, not a recommendation).¹ These are animal figures, and like the studies above they describe rodents, not people.

Side effects and warnings

The side effect information here is taken from the US label, not from anecdote. The contraindications section reads, in full, none known.¹ The most common clinical experience the label reports is transient nausea and vomiting, with less frequent reactions of body odor, nausea, and gastritis; the label adds that the true rate is hard to estimate because of the underlying illness in the patients studied.¹

The serious signal is hypersensitivity. The label warns that serious hypersensitivity reactions, including anaphylaxis, laryngeal edema, and bronchospasm, have been reported, mostly in patients with end stage renal disease undergoing dialysis, some of them within minutes of intravenous administration.¹ Postmarketing reports also include seizures in patients with or without pre existing seizure activity receiving oral or intravenous levocarnitine, with an increase in frequency or severity in those who already had seizures.¹ On interactions, the label notes that INR can rise in people taking warfarin, so INR is monitored after starting levocarnitine or after a dose change.¹ On overdose, the label states there have been no reports of toxicity from overdosage, notes that levocarnitine is easily removed from plasma by dialysis, and says large doses may cause diarrhea.¹ Levocarnitine was not mutagenic in three test organisms, and no long term animal studies of carcinogenic potential have been done.¹ One handling point matters for any injectable: the vial contains no preservative, so the label instructs discarding the unused portion of an opened vial.¹

Event (percent of patients)	Placebo (n=63)	Levocarnitine, pooled (n=130)
Injection site reaction	59	33
Pain	49	30
Flu syndrome	40	25
Headache	16	22
Hypertension	14	20
Hypotension	19	14
Chest pain	14	12
Abdominal pain	17	9
Infection	17	15
Asthenia	8	9
Fever	5	7
Tachycardia	5	6

Reported in two double blind, placebo controlled trials in chronic hemodialysis patients, at 5 percent or greater and regardless of causality. On several rows, including injection site reaction and pain, the placebo rate was higher than the levocarnitine rate, so these figures are not a measure of harm caused by the drug.¹

That last point is the honest read of the table: numbers reported without regard to causality, in very sick patients, where placebo often looked worse than the drug. They are a record of what was observed in trials, not a tally of harms the drug caused. The water and sterility questions that sit behind any injection, whatever the substance, are covered in the note on bacteriostatic versus sterile water.

Status in Vietnam

On 6 September 2026, Long Chau, the largest pharmacy chain in Vietnam, listed levocarnitine only in oral forms. The registered drug products returned were oral solutions and a film coated tablet, for example an oral solution at 1 g per 10 mL and a 330 mg film coated tablet, two of the four labelled for primary and secondary carnitine deficiency.¹⁸ No injectable levocarnitine product appeared across three separate searches on that site, for l-carnitine, for levocarnitin, and for carnitin tiem, the Vietnamese term for carnitine injection.¹⁷¹⁸²² That is a null result read directly from the first page of each search rather than a tooling failure, with the caveat that only the first page of each query was inspected.

A concrete registration record does exist for an oral product: Anbaluti 330 mg levocarnitine tablets carry the Vietnamese marketing authorisation number 893110876124, in a pack of 9 blisters of 10 tablets, and the product page states it is sold only on a doctor's order.¹⁹ On price, Long Chau displayed no price for any of the four registered levocarnitine drug products, every price field returned empty; the only levocarnitine containing record that carried a price was a dietary supplement rather than a registered drug, listed at 580,000 VND for a box of 60 capsules.¹⁸

The authoritative source is the national register held by the Drug Administration of Vietnam. That portal is live and reachable, but its results table loads in the browser after the page arrives, so the register itself could not be queried for this page, and whether an injectable levocarnitine has ever been registered in Vietnam is not established here in either direction.²⁰ A second chain, Pharmacity, returned only an application shell with its product data loaded separately, which is a tooling limit and not evidence that the chain does or does not stock the product.²¹ No Vietnamese clinic page claiming to offer injectable L-carnitine was checked, so nothing is said here about clinic availability. The same registration questions apply to other injectables people research in Vietnam, such as semaglutide.

The short version

Injectable L-carnitine is levocarnitine, a prescription drug, not a supplement and not a peptide.
In the United States it is approved only for carnitine deficiency in inborn errors of metabolism and in dialysis patients, and the label says the effect on clinical outcomes has not been determined.
There is no approved US indication for fat loss, energy, or athletic performance.
The label route is intravenous; the human studies in this set used infusions or intravenous injections, and one was a clean negative for insulin resistance.
Reported risks include serious hypersensitivity reactions, nausea and vomiting, postmarketing seizures, and a warfarin interaction; the contraindications section reads none known.
In Vietnam, only oral levocarnitine products were found on the largest pharmacy chain, and the injectable registration status could not be verified here.

Frequently asked questions

What is injectable L-carnitine used for?+

Injectable L-carnitine, whose pharmaceutical name is levocarnitine, is an approved prescription drug in the United States for two situations the US label defines: the acute and chronic treatment of secondary carnitine deficiency caused by an inborn error of metabolism, and the prevention and treatment of carnitine deficiency in patients with end stage renal disease who are undergoing dialysis. The same label is careful about how far that goes: it states that while raising carnitine concentrations in dialysis patients is demonstrated, the effects on the signs, symptoms, and clinical outcomes of carnitine deficiency have not been determined. There is no approved indication in that label for fat loss, athletic performance, energy, or cosmetic use.

Is injectable L-carnitine approved for fat loss or energy?+

Not in the US label we read. The CARNITOR levocarnitine injection label lists only two approved indications, both of them carnitine deficiency states, and it contains no indication for weight loss, fat burning, athletic performance, energy, or cosmetic use. That is a statement about this specific US label, and it is not a claim about every regulator, because other national registers were not checked here. The practical read is that injecting L-carnitine for body composition or energy is an off label, unapproved use, and the honest evidence for those goals is set out in the sections above rather than assumed.

How is injectable L-carnitine given?+

The US label states that the injection is administered intravenously, and it describes weight based doses given as a slow two to three minute bolus or by infusion, under the monitoring the label recommends, for the deficiency conditions it treats. No sentence in that label authorizes intramuscular or subcutaneous use of the US product. Those figures are label instructions for specific patients under medical supervision, not a recommendation for anyone to inject L-carnitine, and this page does not tell any reader what to take.

What are the side effects of injectable L-carnitine?+

From the US label: transient nausea and vomiting have been observed, and less frequent reactions include body odor, nausea, and gastritis. More seriously, the label warns that serious hypersensitivity reactions, including anaphylaxis, laryngeal edema, and bronchospasm, have been reported, mostly in dialysis patients, some within minutes of intravenous administration. Postmarketing reports include seizures in patients receiving oral or intravenous levocarnitine, and the label notes that INR can rise in people taking warfarin, so INR is monitored. The contraindications section reads, in full, none known. The controlled trial adverse event table is reported regardless of causality, and on several rows the placebo rate was as high as or higher than the levocarnitine rate, so those numbers are not proof of harm caused by the drug.

Is injectable L-carnitine available in Vietnam?+

On the date we checked, 6 September 2026, the largest pharmacy chain in Vietnam, Long Chau, listed levocarnitine only in oral forms, an oral solution and a film coated tablet, and no injectable levocarnitine product appeared across three separate searches on that site. That is a null result within the first page of each search rather than a tooling failure, because the product data was read directly out of the page. The national register held by the Drug Administration of Vietnam is the authoritative source, but its results table loads in the browser and could not be queried here, so whether an injectable levocarnitine has ever been registered in Vietnam is not established by this page in either direction.

Is L-carnitine a peptide?+

No source we fetched calls L-carnitine a peptide. The identity records describe a single small molecule with the formula C7H15NO3 and a molecular weight of about 161 daltons, built on a hydroxybutanoate backbone with a quaternary trimethylammonium group, and with no amino acid residues and no amide bonds. Read against that structure, it is a small molecule quaternary ammonium compound rather than a peptide. That is a structural reading of the identity records, not a quote from them.

Sources & references

1.US National Library of Medicine, DailyMed. Label: CARNITOR (levocarnitine) injection, solution, full prescribing information (Leadiant Biosciences). Label updated November 20, 2023. dailymed.nlm.nih.gov CARNITOR levocarnitine injection
2.PubChem Compound record, levocarnitine, CID 10917: formula C7H15NO3, molecular weight 161.20, CAS 541-15-1. pubchem.ncbi.nlm.nih.gov/compound/10917
3.US FDA, Drugs@FDA (openFDA) records for levocarnitine: originator CARNITOR injection NDA020182 and further injectable applications, all 200 mg per mL, prescription. api.fda.gov Drugs@FDA levocarnitine
4.Effect of L-carnitine on oxidative stress and platelet activation after major surgery. Acta Anaesthesiol Scand, 2011. Randomized controlled trial. PMID 21770897. pubmed.ncbi.nlm.nih.gov/21770897
5.L-carnitine infusion does not alleviate lipid-induced insulin resistance and metabolic inflexibility. PLoS One, 2020. Randomized crossover trial. PMID 32976523. pubmed.ncbi.nlm.nih.gov/32976523
6.Acetyl-L-carnitine infusion increases glucose disposal in type 2 diabetic patients. Metabolism, 2000. Controlled clinical trial. PMID 10877193. Note: this study used acetyl-L-carnitine, not L-carnitine. pubmed.ncbi.nlm.nih.gov/10877193
7.Effects of L-Carnitine Supplementation in Patients Receiving Hemodialysis or Peritoneal Dialysis. Nutrients, 2020. Clinical trial. PMID 33139659. pubmed.ncbi.nlm.nih.gov/33139659
8.Effect of Carnitine Supplementation in Pediatric Patients with Left Ventricular Dysfunction. Pediatr Cardiol, 2023. Retrospective study; dose not stated in the abstract. PMID 36107209. pubmed.ncbi.nlm.nih.gov/36107209
9.Carnitine in parenteral nutrition. Gastroenterology, 2009. Recommendation paper, not a trial. PMID 19874944. pubmed.ncbi.nlm.nih.gov/19874944
10.Secondary carnitine deficiency. J Clin Chem Clin Biochem, 1990. Review. PMID 2199597. pubmed.ncbi.nlm.nih.gov/2199597
11.l-Carnitine and heart disease. Life Sci, 2018. Review. PMID 29241711. pubmed.ncbi.nlm.nih.gov/29241711
12.L-carnitine attenuates autophagic flux, apoptosis, and necroptosis in rats with dexamethasone-induced non-alcoholic steatohepatitis. BMC Pharmacol Toxicol, 2024. Animal study, rat, intraperitoneal. PMID 39736705. pubmed.ncbi.nlm.nih.gov/39736705
13.The effect of sodium benzoate, L-carnitine, and phenylacetate on valproate-induced hyperammonemia in Male Wistar rats. Int J Physiol Pathophysiol Pharmacol, 2022. Animal study, rat, intraperitoneal. PMID 36741198. pubmed.ncbi.nlm.nih.gov/36741198
14.Acetyl-L-carnitine improves erectile function in bilateral cavernous nerve injury rats via promoting cavernous nerve regeneration. Andrology, 2022. Animal study, rat, intraperitoneal; compound is acetyl-L-carnitine. PMID 35420721. pubmed.ncbi.nlm.nih.gov/35420721
15.The intestinal microbial metabolite acetyl l-carnitine improves gut inflammation and immune homeostasis via CADM2. Biochim Biophys Acta Mol Basis Dis, 2024. Animal study, mouse, intraperitoneal; dose not stated in the abstract. PMID 38369215. pubmed.ncbi.nlm.nih.gov/38369215
16.L-carnitine counteracts prepubertal exposure to cisplatin induced impaired sperm in adult rats by preventing germ cell apoptosis. Biotech Histochem, 2018. Animal study, rat; injection route and dose not stated in the abstract. PMID 29388451. pubmed.ncbi.nlm.nih.gov/29388451
17.Nha thuoc Long Chau pharmacy, site search for l-carnitine (300 results returned). Fetched 6 September 2026. nhathuoclongchau.com.vn search l-carnitine
18.Nha thuoc Long Chau pharmacy, site search for levocarnitin (284 results returned): registered levocarnitine products in oral forms only; no price shown for the registered drug products. Fetched 6 September 2026. nhathuoclongchau.com.vn search levocarnitin
19.Nha thuoc Long Chau pharmacy, product page for Anbaluti 330 mg oral levocarnitine tablets, marketing authorisation number 893110876124, prescription only. Fetched 6 September 2026. nhathuoclongchau.com.vn Anbaluti 330mg
20.Cuc Quan ly Duoc (Drug Administration of Vietnam), public marketing authorisation portal. Results table loads client side and could not be queried. Fetched 6 September 2026. dichvucong.dav.gov.vn marketing authorisation portal
21.Pharmacity pharmacy, site search for levocarnitin: an application shell with product data loaded separately (tooling limit, not evidence of absence). Fetched 6 September 2026. pharmacity.vn search levocarnitin
22.Nha thuoc Long Chau pharmacy, site search for carnitin tiem, the Vietnamese for carnitine injection (199 results returned): no carnitine injection product returned. Fetched 6 September 2026. nhathuoclongchau.com.vn search carnitin tiem