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Dietary supplement

L-Carnitine Ingredients & Drug Interactions

by Allergy Research Group

Tablet Or Pill Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
The interaction bottom line Most serious interaction: Moderate

L-Carnitine is a dietary supplement by Allergy Research Group with 1 active ingredient. Its ingredients are commonly taken for exercise performance and recovery, heart health, weight management.Based on those ingredients, 19 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are L-Carnitine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of L-Carnitine by Allergy Research Group

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: L-carnitine, an amino acid your body uses to move fats into cells so they can be burned for energy. It's a single-ingredient supplement, so what you're getting is L-carnitine in tablet form with standard inactive ingredients like microcrystalline cellulose (a binder) and magnesium stearate.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed

This product doesn't appear to be marketed for a specific use, so we graded L-carnitine's overall clinical evidence instead.

Strong

Strong clinical evidence supports L-carnitine for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: L-carnitine deficiency — rated "Effective" (Natural Medicines).
  • On file: Angina — rated "Possibly Effective" (Natural Medicines).
  • On file: Congestive heart failure (CHF) — rated "Possibly Effective" (Natural Medicines).
  • On file: Hyperlipidemia — rated "Possibly Effective" (Natural Medicines).
  • On file: Myocarditis — rated "Possibly Effective" (Natural Medicines).

L-Carnitine is effective for treating L-carnitine deficiency itself. For other uses — including high cholesterol (hyperlipidemia), heart failure, and angina — the evidence shows it's possibly effective, meaning there's some promise but the data isn't definitive enough to say it works reliably.

The research on these uses is still developing.

The evidence, ingredient by ingredient L-carnitine

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

L-Carnitine is generally well tolerated at typical doses, though higher doses can cause stomach upset, diarrhea, nausea, heartburn, and abdominal cramps. Some people report a fishy body odor.

Seizures have been reported very rarely. There isn't enough reliable safety data for L-Carnitine overall, so it should only be used under medical supervision.

For breastfeeding, safety data is limited; caution is advised, and you should talk with your doctor or pharmacist about whether it's right for you.

Side effects, ingredient by ingredient L-carnitine

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — L-carnitine.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 19 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Check before taking if you're on blood thinners (anticoagulants), especially warfarin or acenocoumarol — L-Carnitine can increase their strength and raise bleeding risk. Also flag it if you take thyroid replacement hormone, since L-Carnitine may reduce how well it works.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with strong clinical evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

L-Carnitine makes sense if you have a documented L-carnitine deficiency or want to explore it for heart health under a doctor's care. If you take blood thinners like warfarin or acenocoumarol, or thyroid replacement hormone, you need to check with your own doctor or pharmacist first — this supplement could interfere with how well those medications work.

Either way, run your full medication list through the interaction checker on this page.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Dec 23, 2015.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about L-Carnitine, straight from the product label.

Brand Allergy Research Group
Barcode (UPC) 713947706408
Net contents 40 Tablet(s)
Market status On market
Date entered into DSLD Dec 23, 2015
DSLD ID 54205
Product type Non-nutrient/non-botanical
Supplement form Tablet Or Pill
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years), No Allergies
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for L-Carnitine by Allergy Research Group, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
Servings per container
40
UPC/BARCODE
713947706408
IngredientAmount% DV
L-Carnitine250 mg--

Other ingredients: Microcrystalline Cellulose, Dicalcium Phosphate, Silicon Dioxide, Magnesium Stearate, Stearic Acid, Croscarmellose Sodium

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
General Statements

L-carnitine is considered a semi-essential amino acid. Free form amino acid, high purity, well tolerated, and in tablet form to insure potency.

Suggested/Recommended/Usage/Directions

Suggested Use As a dietary supplement, 1 tablet one or four times daily with meals, or as directed by a healthcare practitioner.

General

Rev. 005

FDA Statement of Identity

dietary supplement

Formula

Hypoallergenic

Storage

Keep in a cool, dry place, tightly capped.

See for yourself

L-Carnitine by Allergy Research Group label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

What’s inside

The Ingredients in L-Carnitine by Allergy Research Group

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Tablet(s) Dosage formTablet Or Pill Servings per container40 Amounts shown are per serving.

L-Carnitine

Interacts with
19 drugs
250 mg per serving

L-carnitine is a compound your body makes naturally and also gets from foods like meat. It helps cells turn fat into energy, and supplements are most...

L-Carnitine monograph & interactions

Other (inactive) ingredients: Microcrystalline Cellulose, Dicalcium Phosphate, Silicon Dioxide, Magnesium Stearate, Stearic Acid, Croscarmellose Sodium. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Carnitine by Allergy Research Group Drug Interactions

Want to check YOUR meds against L-Carnitine?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

Go to the checker
19Drugs
19 Moderate

Ingredients driving the most interactions

Each ingredient & the kinds of drugs it affects

For each ingredient in L-Carnitine with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

L-Carnitine3 drug types · 19 drugs

Acenocoumarol (Sintrom)

Theoretically, L-carnitine might increase the anticoagulant effects of acenocoumarol.
L-carnitine might enhance the anticoagulant effects of acenocoumarol, an oral anticoagulant similar to warfarin, but shorter-acting. There are at least two case reports of INR elevation with concomitant use. In one case, a 33-year-old male with a previously stable INR had an elevated INR of 4.65 after L-carnitine was started and continued for 10 weeks. INR normalized after discontinuation of the L-carnitine-containing product.

Likelihood Possible Evidence D
Thyroid Hormone

Theoretically, L-carnitine might decrease the effectiveness of thyroid hormone replacement.
L-carnitine appears to act as a peripheral thyroid hormone antagonist by inhibiting entry of thyroid hormone into the nucleus of cells. Taking L-carnitine also seems to diminish some of the symptoms of hyperthyroidism.

Likelihood Probable Evidence B
Warfarin (Coumadin)

Theoretically, L-carnitine might increase the anticoagulant effects of warfarin.
L-carnitine might increase the anticoagulant effects of acenocoumarol, a shorter-acting oral anticoagulant similar to warfarin. There is not enough information to know whether this interaction occurs with L-carnitine and warfarin.

Likelihood Possible Evidence D
The maker

Brand information

Manufacturer and brand details for L-Carnitine, from the product label.

Allergy Research Group

See all Allergy Research Group products
Name
Allergy Research Group
City
Alameda
State
CA
ZipCode
94502
Phone Number
510-263-2000
Web Address
www.allergyresearchgroup.com
Pharmacist Counseling Corner

L-Carnitine by Allergy Research Group: Common Questions

Does L-Carnitine by Allergy Research Group interact with any medications?
Yes. Based on its ingredients, L-Carnitine has a known interaction with 19 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
L-Carnitine contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is L-Carnitine effective for weight loss?
The data we have on file covers L-carnitine deficiency, high cholesterol, heart failure, and angina — not weight loss. We don't have effectiveness information for that use.
Can I take this while breastfeeding?
L-Carnitine is rated possibly safe while breastfeeding, but safety data is limited. Talk with your doctor or pharmacist before taking it — they can weigh the pros and cons for your situation.
What are the most common side effects?
Stomach-related side effects are most common: nausea, diarrhea, heartburn, abdominal cramps, and reduced appetite. Some people also notice a fishy body odor. These tend to happen more at higher doses.
Is there safety data for pregnancy?
We don't have pregnancy safety data on file for L-Carnitine. If you're pregnant or planning to be, talk with your doctor or pharmacist — they'll help you figure out whether it's right for you.
Can I take this if I have heart disease?
L-Carnitine is rated possibly effective for angina and heart failure and may actually lower your risk of certain heart problems. But because of potential interactions with blood thinners and thyroid medication, and because there isn't enough safety data overall, use it only under your doctor's supervision.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

L-Carnitine label
Sources

Sources & How We Checked

L-Carnitine's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 41 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

L-carnitine 41 references
  1. Ellaway CM, Williams K, Leonard H, et al. Rett syndrome: randomized controlled trial of L-carnitine. J Child Neurol 1999;14:162-7. PubMed
  2. Anon. Carnitor (levocarnitine) package insert. Sigma-Tau Pharmaceuticals Inc, Gaithersburg, MD. December 1999.
  3. Cherchi A, Lai C, Angelino F, et al. Effects of L-carnitine on exercise tolerance in chronic stable angina: a multicenter, double-blind, randomized, placebo-controlled, crossover study. Int J Clin Pharmacol Ther Toxicol 1985;23:569-72.
  4. Plioplys AV, Plioplys S. Amantadine and L-carnitine treatment of Chronic Fatigue Syndrome. Neuropsychobiology 1997;35:16-23. PubMed
  5. Benvenga S, Ruggeri RM, Russo A, et al. Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial. J Clin Endocrinol Meta
  6. Martinez E, Domingo P, Roca-Cusachs A. Potentiation of acenocoumarol action by L-carnitine. J Intern Med 1993;233:94.
  7. Bachmann HU, Hoffmann A. Interaction of food supplement L-carnitine with oral anticoagulant acenocoumarol. Swiss Med Wkly 2004;134:385. PubMed
  8. Evans AM, Fornasini G. Pharmacokinetics of L-carnitine. Clin Pharmacokinet 2003;42:941-67. PubMed
  9. 12761 Benvenga S, Amato A, Calvani M, Trimarchi F. Effects of carnitine on thyroid hormone action. Ann N Y Acad Sci 2004;1033:158-67. PubMed
  10. Ciacci C, Peluso G, Iannoni E, et al. L-Carnitine in the treatment of fatigue in adult celiac disease patients: a pilot study. Dig Liver Dis 2007;39:922-8. PubMed
  11. Cruciani RA, Dvorkin E, Homel P, et al. Safety, tolerability and symptom outcomes associated with L-carnitine supplementation in patients with cancer, fatigue, and carnitine deficiency: a phase I/II study. J Pain Symptom Manage 2006;32:551-9. PubMed
  12. Lebrun C, Alchaar H, Candito M, et al. Levocarnitine administration in multiple sclerosis patients with immunosuppressive therapy-induced fatigue. Mult Scler 2006;12:321-4. PubMed
  13. Malaguarnera M, Cammalleri L, Gargante MP, et al. L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial. Am J Clin Nutr 2007;86:1738-44. PubMed
  14. Mantovani G, Maccio A, Madeddu C, et al. Randomized phase III clinical trial of five different arms of treatment in 322 patients with cancer cachexia. Oncologist 2010;15:200-11.
  15. Angelova-Fischer I, Rippke F, Fischer TW, Neufang G, Zillikens D. A double-blind, randomized, vehicle-controlled efficacy assessment study of a skin care formulation for improvement of mild to moderately severe acne. J Eur Acad Dermatol Venereol. 2013 Jul PubMed
  16. Hatamkhani S, Khalili H, Karimzadeh I, Dashti-Khavidaki S, Abdollahi A, Jafari S. Carnitine for prevention of antituberculosis drug-induced hepatotoxicity: a randomized, clinical trial. J Gastroenterol. Hepatol. 2014 May;29(5):997-1004. PubMed
  17. Boehm G, Stahl B. Oligosaccharides from milk. J Nutr 2007;137(3 Suppl 2):847S-849S.
  18. Van Oudheusden, L. J. and Scholte, H. R. Efficacy of carnitine in the treatment of children with attention-deficit hyperactivity disorder. Prostaglandins Leukot.Essent.Fatty Acids 2002;67(1):33-38. PubMed
  19. Derosa, G., Cicero, A. F., Gaddi, A., Mugellini, A., Ciccarelli, L., and Fogari, R. The effect of L-carnitine on plasma lipoprotein(a) levels in hypercholesterolemic patients with type 2 diabetes mellitus. Clin Ther 2003;25(5):1429-1439. PubMed
  20. Foitzik, K., Hoting, E., Heinrich, U., Tronnier, H., and Paus, R. Indications that topical L-carnitin-L-tartrate promotes human hair growth in vivo. J Dermatol.Sci 2007;48(2):141-144. PubMed
  21. Kumar, A., Singh, R. B., Saxena, M., Niaz, M. A., Josh, S. R., Chattopadhyay, P., Mechirova, V., Pella, D., and Fedacko, J. Effect of carni Q-gel (ubiquinol and carnitine) on cytokines in patients with heart failure in the Tishcon study. Acta Cardiol. 20
  22. Cruciani, R. A., Dvorkin, E., Homel, P., Culliney, B., Malamud, S., Lapin, J., Portenoy, R. K., and Esteban-Cruciani, N. L-carnitine supplementation in patients with advanced cancer and carnitine deficiency: a double-blind, placebo-controlled study. J Pa PubMed
  23. Malaguarnera, M., Vacante, M., Avitabile, T., Malaguarnera, M., Cammalleri, L., and Motta, M. L-Carnitine supplementation reduces oxidized LDL cholesterol in patients with diabetes. Am J Clin.Nutr 2009;89(1):71-76. PubMed
  24. Alvarez, T. M., Guardiola, P. D., Roldan, J. O., Elviro, R., Wevers, R., and Guijarro, G. [Primary trimethylaminuria: the fish odor syndrome]. Endocrinol.Nutr. 2009;56(6):337-340.
  25. Wu, Z. M., Lu, X., Wang, Y. W., Sun, J., Tao, J. W., Yin, F. H., and Cheng, H. J. [Short-term medication of L-carnitine before intracytoplasmic sperm injection for infertile men with oligoasthenozoospermia]. Zhonghua Nan.Ke.Xue 2012;18(3):253-256.
  26. Tarighat, Esfanjani A., Mahdavi, R., Ebrahimi, Mameghani M., Talebi, M., Nikniaz, Z., and Safaiyan, A. The effects of magnesium, L-carnitine, and concurrent magnesium-L-carnitine supplementation in migraine prophylaxis. Biol.Trace Elem.Res 2012;150(1-3): PubMed
  27. DiNicolantonio, J. J., Lavie, C. J., Fares, H., Menezes, A. R., and O'Keefe, J. H. L-carnitine in the secondary prevention of cardiovascular disease: systematic review and meta-analysis. Mayo Clin Proc. 2013;88(6):544-551. PubMed
  28. Huang, W. W., Wang, M. Y., Shi, H. M., Peng, Y., Peng, C. S., Zhang, M., Li, Y., Lu, J., and Li, X. B. Comparative study of bioactive constituents in crude and processed Glycyrrhizae radix and their respective metabolic profiles in gastrointestinal tract
  29. Madsen KL, Preisler N, Orngreen MC, Andersen SP, Olesen JH, Lund AM, Vissing J. Patients with medium-chain acyl-coenzyme a dehydrogenase deficiency have impaired oxidation of fat during exercise but no effect of L-carnitine supplementation. J Clin Endocri
  30. Prohaska ES, Muzyk AJ, Rivelli SK. Levocarnitine-induced hypophosphatemia in a hemodialysis patient with acute valproic acid toxicity. J Neuropsychiatry Clin Neurosci. 2012 Winter;24(1):E18-9. PubMed
  31. Shang R, Sun Z, Li H. Effective dosing of L-carnitine in the secondary prevention of cardiovascular disease: a systematic review and meta-analysis. BMC Cardiovasc Disord. 2014 Jul 21;14:88. PubMed
  32. Zhang JJ, Wu ZB, Cai YJ, Ke B, Huang YJ, Qiu CP, Yang YB, Shi LY, Qin J. L-carnitine ameliorated fasting-induced fatigue, hunger, and metabolic abnormalities in patients with metabolic syndrome: a randomized controlled study. Nutr J. 2014 Nov 26;13:110. PubMed
  33. Koeth RA, Wang Z, Levison BS, Buffa JA, Org E, Sheehy BT, Britt EB, Fu X, Wu Y, Li L, Smith JD, DiDonato JA, Chen J, Li H, Wu GD, Lewis JD, Warrier M, Brown JM, Krauss RM, Tang WH, Bushman FD, Lusis AJ, Hazen SL. Intestinal microbiota metabolism of L-carn
  34. Jun DW, Kim BI, Cho YK, Kim HJ, Kwon YO, Park SY, Han SY, Baek YH, Jung YJ, Kim HY, Kim W, Heo J, Woo HY, Hwang SG, Rim KS, Choi JY, Bae SH, Lee YS, Lim YS,Cheong JY, Cho SW, Lee BS, Kim SH, Sohn JH, Kim TY, Paik YH, Kim JK, Lee KS. Efficacy and safety of
  35. An JH, Kim YJ, Kim KJ, et al. L-carnitine supplementation for the management of fatigue in patients with hypothyroidism on levothyroxine treatment: a randomized, double-blind, placebo-controlled trial. Endocr J. 2016;63(10):885-95. PubMed
  36. Chen N, Yang M, Zhou M, Xiao J, Guo J, He L. L-carnitine for cognitive enhancement in people without cognitive impairment. Cochrane Database Syst Rev. 2017;3:CD009374. PubMed
  37. Khajeh B, Dashti-Khavidaki S, Nasiri-Toosi M, Mohammadi K, Jafari A. Effects of pre-transplant L-carnitine supplementation on primary graft dysfunction in liver transplant recipients: a pilot, randomized, placebo-controlled clinical trial. Res Pharm Sci. PubMed
  38. Kubota K, Uojima H, Shao X, et al. Additional L-carnitine Reduced the Risk of Hospitalization in Patients with Overt Hepatic Encephalopathy on Rifaximin. Dig Dis 2021. PubMed
  39. Amini L, Yaghini O, Ghazavi M, Aslani N. L-carnitine versus propranolol for pediatric migraine prophylaxis. Iran J Child Neurol 2021;15(2):77-86.
  40. Shakibaei F, Jelvani D. Effect of adding l -carnitine to risperidone on behavioral, cognitive, social, and physical symptoms in children and adolescents with autism: A randomized double-blinded placebo-controlled clinical trial. Clin Neuropharmacol 2023;4 PubMed
  41. Moustafa I, Connolly C, Anis M, Mustafa H, Oosthuizen F, Viljoen M. A prospective study to evaluate the efficacy and safety of vitamin E and levocarnitine prophylaxis against doxorubicin-induced cardiotoxicity in adult breast cancer patients. J Oncol Phar PubMed

See these in context on the L-carnitine monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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