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Dietary supplement

Acetyl L-Carnitine 1000mg Ingredients & Drug Interactions

by Best Naturals

Acetyl L-Carnitine 1000mg label
See full label image
Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 30, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Acetyl L-Carnitine 1000mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Acetyl L-Carnitine 1000mg is a dietary supplement by Best Naturals with 1 active ingredient. Its ingredients are commonly taken for memory and cognitive support, nerve pain (neuropathy), energy and fatigue.Based on those ingredients, 203 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Acetyl L-Carnitine HCl. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Acetyl L-Carnitine 1000mg by Best Naturals

Ask about any prescription or over-the-counter medication and we check it for interactions with Acetyl L-Carnitine 1000mg by Best Naturals — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Acetyl L-Carnitine 1000mg by Best Naturals

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

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

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: acetyl-L-carnitine HCl, a form of carnitine that your body uses to help convert fat into energy and support brain function. The capsule also contains inactive ingredients — microcrystalline cellulose, silicon dioxide, and magnesium stearate — which are fillers and binders that help form the capsule.

Does it work?

Moderate 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
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: cellular energy production and fat metabolism.
  • We looked for evidence on: Age-related cognitive decline, Athletic performance, Cancer-related fatigue, Chronic fatigue syndrome (CFS), Multiple sclerosis-related fatigue, mitochondrial function — and 2 related terms.
  • The strongest evidence on file: Acetyl-l-carnitine is rated "Possibly Effective" for Age-related cognitive decline (Natural Medicines).
  • Also on file: Acetyl-l-carnitine is rated "Insufficient Reliable Evidence To Rate" for Athletic performance, Cancer-related fatigue, Chronic fatigue syndrome (CFS), Multiple sclerosis-related fatigue.

Acetyl-L-carnitine is rated possibly effective for several conditions based on available evidence: age-related cognitive decline, Alzheimer disease, alcohol use disorder, diabetic nerve damage (neuropathy), and depression. That means there's some promise in the research, but the evidence isn't yet conclusive.

If you're considering it for one of these reasons, talk with your doctor or pharmacist about whether it makes sense for your situation.

The evidence, ingredient by ingredient Acetyl-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.

Acetyl-L-carnitine is generally well tolerated in the short term, but long-term safety hasn't been fully studied. The most common side effects are agitation, dry mouth, headache, trouble sleeping, and loss of appetite.

Some people also report a fishy odor in urine, breath, or sweat — that's from a breakdown product of the supplement. Less commonly, it may cause nausea, vomiting, diarrhea, constipation, or abdominal upset, though these don't show up more often than placebo in most studies.

In people with Alzheimer disease, psychiatric side effects like depression, mood changes, confusion, or aggression have been reported, though it's unclear whether the supplement or the condition itself is responsible. There isn't enough safety information to recommend this during breastfeeding, so it's best avoided unless your doctor advises otherwise.

Pregnancy and safety data are not on file.

Side effects, ingredient by ingredient Acetyl-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 — Acetyl-l-carnitine.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 203 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.

Before you take this, double-check with your pharmacist or doctor if you're on serotonergic drugs (like antidepressants or certain pain medications) — Moderate severity interaction. Also check if you take warfarin (Coumadin) or acenocoumarol (Sintrom), blood thinners that this supplement may strengthen.

If you're on thyroid hormone replacement, that's another one to review. Use the search tool on this page to verify your specific medications.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Acetyl-L-carnitine may be worth considering if you're interested in supporting brain health or managing one of the possibly effective conditions — but only after you've checked your medications with your pharmacist or doctor. If you take serotonergic drugs, blood thinners, or thyroid medication, this product requires a careful look before you start.

Talk to us before adding it to your routine.

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 Jun 16, 2022.

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 Acetyl L-Carnitine 1000mg, straight from the product label.

Brand Best Naturals
Barcode (UPC) 817716014234
Net contents 60 Capsule(s)
Market status On market
Date entered into DSLD Jun 16, 2022
DSLD ID 270287
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free
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 Acetyl L-Carnitine 1000mg by Best Naturals, 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 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
60
UPC/BARCODE
817716014234
IngredientAmount% DV
Acetyl L-Carnitine HCl1000 mg--

Other ingredients: Capsule, Microcrystalline Cellulose, Silicon Dioxide, Magnesium Stearate

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.
Formula

Acetyl-L-Carnitine is a modified amino acid that supports cellular energy production by assisting in the transport of fat into the mitochondria where it is oxidized and converted into ATP (chemical energy for the cell). Certain research publications indicate that Acetyl L-Carnitine may help support the following: Support healthy cellular energy metabolism. Support brain & nervous system function.

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement, take one (1) twice daily, between meals, or as directed by your qualified healthcare professional. Consider taking this product in combination with Best Naturals Pantothenic Acid, Choline and Mind Alert.

Precautions

Keep out of the reach of children.

Do not use if safety seal is broken or missing.

Caution: For adults only, if you are pregnant, nursing, taking any medications or have any medical condition, consult your doctor before use.

Caution: For adults only, if you are pregnant, nursing, taking any medications or have any medical condition, consult your doctor before use. Discontinue use and consult your doctor if any adverse reactions occur.

Storage

Keep in cool, dry place.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Seals/Symbols

Made in USA

GMP Good Manufacturing Practice Product

Formulation

Premium formula

3rd party lab tested

No artificial color, flavor or sweetener, no preservatives, no sugar, no starch, no corn, no soy, no egg, no milk, no lactose, no gluten, no wheat, no yeast, no fish. Sodium free.

FDA Statement of Identity

Dietary Supplement

General Statements

For additional information call 1-877-659-6004

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Acetyl L-Carnitine 1000mg by Best Naturals label

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

Acetyl L-Carnitine 1000mg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Acetyl L-Carnitine 1000mg by Best Naturals

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

Serving size1 Capsule(s) Dosage formCapsule Servings per container60 Amounts shown are per serving.

Acetyl L-Carnitine HCl

Interacts with
203 drugs
1000 mg per serving

Acetyl-L-carnitine is a form of the amino acid carnitine that the body uses to help produce energy in cells. It is most studied for nerve pain and mem...

Acetyl L-Carnitine HCl monograph & interactions

Other (inactive) ingredients: Capsule, Microcrystalline Cellulose, Silicon Dioxide, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Acetyl L-Carnitine 1000mg by Best Naturals Drug Interactions

Want to check YOUR meds against Acetyl L-Carnitine 1000mg?

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
203Drugs
203 Moderate

Ingredients driving the most interactions

Acetyl L-Carnitine HCl 203

Individual Drug Interactions

The ingredients in Acetyl L-Carnitine 1000mg interact with 203 drugs. Click any drug to see the details.

1 of the 1 ingredient in Acetyl L-Carnitine 1000mg interact with drugs. Each result below shows which ingredient is responsible. Acetyl L-Carnitine HCl

Each ingredient & the kinds of drugs it affects

For each ingredient in Acetyl L-Carnitine 1000mg 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.

Acetyl L-Carnitine HCl4 drug types · 203 drugs

Acenocoumarol (Sintrom)

Theoretically, acetyl-L-carnitine might increase the anticoagulant effects of acenocoumarol.
L-carnitine, the parent compound of acetyl-L-carnitine, might enhance the anticoagulant effects of acenocoumarol, an oral anticoagulant that is similar to warfarin, but shorter-acting. There are at least two case reports of INR elevation when L-carnitine was taken with acenocoumarol. 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. It is unclear if such an interaction would also occur with acetyl-L-carnitine.

Likelihood Possible Evidence D
Serotonergic Drugs

Theoretically, acetyl-L-carnitine might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders, when taken with serotonergic drugs.
Animal research shows that acetyl-L-carnitine can increase levels of serotonin in the brain.

Likelihood Possible Evidence D
Thyroid Hormone

Theoretically, acetyl-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. It is unclear if such an interaction would occur with acetyl-L-carnitine.

Likelihood Probable Evidence B
Warfarin (Coumadin)

Theoretically, acetyl-L-carnitine might increase the anticoagulant effects of warfarin.
L-carnitine, the parent compound of acetyl-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 acetyl-L-carnitine and warfarin.

Likelihood Possible Evidence D
Acetyl L-Carnitine HCl full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Acetyl L-Carnitine 1000mg, from the product label.

Best Naturals

See all Best Naturals products
Name
Best Naturals
Street Address
PO Box 394
City
Kenilworth
State
NJ
ZipCode
07033
Phone Number
1-877-659-6004
Web Address
www.shopbestnaturals.com
Pharmacist Counseling Corner

Acetyl L-Carnitine 1000mg by Best Naturals: Common Questions

Does Acetyl L-Carnitine 1000mg by Best Naturals interact with any medications?
Yes. Based on its ingredients, Acetyl L-Carnitine 1000mg has a known interaction with 203 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Acetyl L-Carnitine 1000mg 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.
What does acetyl-L-carnitine actually do?
Your body uses it to help convert fat into energy and support how your brain works. It's a form of carnitine, a naturally occurring compound. Research suggests it may help with cognitive decline, Alzheimer disease, alcohol use disorder, diabetic nerve damage, and depression, though the evidence is still developing.
What are the most common side effects?
Agitation, dry mouth, headache, insomnia, and reduced appetite are the most reported. Some people notice a fishy smell in their urine, breath, or sweat. Nausea, vomiting, diarrhea, and constipation can happen too, but they don't occur more often than with placebo in most studies.
Is this safe to take long-term?
Short-term use is generally well tolerated, but long-term safety hasn't been fully established, so we don't have solid data on that yet. If you're thinking about taking it regularly, check with your doctor.
Can I take this while breastfeeding?
There isn't enough safety information to know either way, so it's safer to avoid it unless your doctor advises otherwise. Talk with them about whether it's right for your situation.
Why do I need to check my blood thinner with this?
Acetyl-L-carnitine may theoretically strengthen how warfarin and similar blood thinners work, which could increase your bleeding risk. It's a Moderate severity interaction, so your pharmacist needs to review your specific medication before you start.

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.

Acetyl L-Carnitine 1000mg label
Go deeper

The Full Monographs Behind Acetyl L-Carnitine 1000mg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Acetyl-l-carnitine

Interacts with 203 drugs

Acetyl-L-carnitine is a form of the amino acid carnitine that the body uses to help produce energy in cells. It is most studied for nerve pain and memory-related conditions, though the evide...

Read the full Acetyl-l-carnitine monograph →
Sources

Sources & How We Checked

Acetyl L-Carnitine 1000mg'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 22 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.

Acetyl-l-carnitine 22 references
  1. Thal LJ, Carta A, Clarke WR, et al. A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer's Disease. Neurology 1996;47:705-11. PubMed
  2. Sano M, Bell K, Cote L, et al. Double-blind parallel design pilot study of acetyl levocarnitine in patients with Alzheimer's Disease. Arch Neurol 1992;49:1137-41. PubMed
  3. Spagnoli A, Lucca U, Menasce G, et al. Long-term acetyl-L-carnitine treatment in Alzheimer's Disease. Neurology 1991;41:1726-32. PubMed
  4. Brooks JO 3rd, Yesavage JA, Carta A, Bravi D. Acetyl L-carnitine slows decline in younger patients with Alzheimer's disease: a reanalysis of a double-blind, placebo-controlled study using the trilinear approach. Int Psychoger 1998;10:193-203. PubMed
  5. Pettegrew JW, Klunk WE, Panchalingam K, et al. Clinical and neurochemical effects of acetyl-L-carnitine in Alzheimer's disease. Neurobiol Aging 1995;16:1-4. PubMed
  6. Rai G, Wright G, Scott L, et al. Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer's dementia. Curr Med Res Opin 1990;11:638-47. PubMed
  7. 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
  8. Montgomery SA, Thal LJ, Amrein R. Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer's disease. Int Clin Psychopharmacol 2003;18:61-71.. PubMed
  9. Martinez E, Domingo P, Roca-Cusachs A. Potentiation of acenocoumarol action by L-carnitine. J Intern Med 1993;233:94.
  10. Hudson S, Tabet N. Acetyl-L-carnitine for dementia. Cochrane Database Syst Rev 2003;2:CD003158.. PubMed
  11. Bachmann HU, Hoffmann A. Interaction of food supplement L-carnitine with oral anticoagulant acenocoumarol. Swiss Med Wkly 2004;134:385. PubMed
  12. De Grandis D, Minardi C. Acetyl-L-carnitine (levacecarnine) in the treatment of diabetic neuropathy. A long-term, randomised, double-blind, placebo-controlled study. Drugs R D 2002;3:223-31. PubMed
  13. 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
  14. Sima AAF, Calvani M, Mehra M, et al. Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: An analysis of two randomized, placebo-controlled trials. Diabetes Care 2005;28:89-94.
  15. Youle, M. and Osio, M. A double-blind, parallel-group, placebo-controlled, multicentre study of acetyl L-carnitine in the symptomatic treatment of antiretroviral toxic neuropathy in patients with HIV-1 infection. HIV.Med. 2007;8(4):241-250.
  16. Brennan BP, Jensen JE, Hudson JI, Coit CE, Beaulieu A, Pope HG Jr, Renshaw PF, Cohen BM. A placebo-controlled trial of acetyl-L-carnitine and a-lipoic acid in the treatment of bipolar depression. J Clin Psychopharmacol. 2013 Oct;33(5):627-35.
  17. Ledinek AH, Sajko MC, Rot U. Evaluating the effects of amantadin, modafinil and acetyl-L-carnitine on fatigue in multiple sclerosis--result of a pilot randomized, blind study. Clin Neurol Neurosurg. 2013 Dec;115 Suppl 1:S86-9. PubMed
  18. Martinotti G, Andreoli S, Reina D, Di Nicola M, Ortolani I, Tedeschi D, Fanella F, Pozzi G, Iannoni E, D'Iddio S, Prof LJ. Acetyl-l-Carnitine in the treatment of anhedonia, melancholic and negative symptoms in alcohol dependent subjects. Prog Neuropsychop PubMed
  19. Baek SM, Zheng R, Seo EJ, Hwang DY, Kim BH. Pharmacokinetic comparisons of two acetyl-L-carnitine formulations in healthy Korean volunteers. Int J Clin Pharmacol Ther. 2015;53(11):980-6. PubMed
  20. Goodison G, Overeem K, de Monte V, Siskind D. Mania associated with self-prescribed acetyl-l-carnitine in a man with bipolar I disorder. Australas Psychiatry. 2017;25(1):13-4.
  21. Bruno A, Pandolfo G, Crucitti M, Lorusso S, Zoccali RA, Muscatello MR. Acetyl-L-Carnitine Augmentation of Clozapine in Partial-Responder Schizophrenia: A 12-Week, Open-Label Uncontrolled Preliminary Study. Clin Neuropharmacol. 2016;39(6):277-80. PubMed
  22. Veronese N, Stubbs B, Solmi M, Ajnakina O, Carvalho AF, Maggi S. Acetyl-L-Carnitine Supplementation and the Treatment of Depressive Symptoms: A Systematic Review and Meta-Analysis. Psychosom Med. 2018;80(2):154-9. PubMed

See these in context on the Acetyl-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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