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Dietary supplement

Acetyl L-Carnitine 250 mg Ingredients & Drug Interactions

by Klaire Labs

Acetyl L-Carnitine 250 mg label
See full label image
Capsule Category: Amino Acid/protein
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Acetyl L-Carnitine 250 mg 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 250 mg is a dietary supplement by Klaire Labs 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. 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 250 mg by Klaire Labs

Ask about any prescription or over-the-counter medication and we check it for interactions with Acetyl L-Carnitine 250 mg by Klaire Labs — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Acetyl L-Carnitine 250 mg by Klaire Labs

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 12, 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, a compound your body naturally makes from the amino acid carnitine. The inactive ingredients are a vegetarian capsule, L-leucine, silicon dioxide, and cellulose.

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

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

Moderate

Some clinical evidence supports Acetyl-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: Age-related cognitive decline — rated "Possibly Effective" (Natural Medicines).
  • On file: Alcohol use disorder — rated "Possibly Effective" (Natural Medicines).
  • On file: Alzheimer disease — rated "Possibly Effective" (Natural Medicines).
  • On file: Depression — rated "Possibly Effective" (Natural Medicines).
  • On file: Diabetic neuropathy — rated "Possibly Effective" (Natural Medicines).

Acetyl-L-carnitine is possibly effective for age-related cognitive decline, Alzheimer disease, alcohol use disorder, diabetic neuropathy, and depression, according to the evidence we hold. That means some studies suggest it may help, but the data isn't conclusive yet.

If you're considering it for one of these concerns, it's worth a conversation with your doctor about whether a trial makes sense for you.

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 short-term, but long-term safety isn't fully established. The most common side effects are agitation, dry mouth, headache, insomnia, and reduced appetite.

It may also cause nausea, vomiting, diarrhea, or constipation, though these aren't much more common than placebo. One quirk: a breakdown product can cause a fishy odor in urine, breath, and sweat.

There isn't enough reliable safety data to recommend this during pregnancy. Safety while breastfeeding is unknown, so it's best avoided unless your doctor advises otherwise.

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 taking this product, double-check if you're on serotonergic drugs like antidepressants or migraine medications (Moderate risk), blood thinners such as warfarin or acenocoumarol (Moderate risk), or thyroid hormone replacement (Moderate risk). Use the search tool on this page with your exact medication names.

Check your own medication Run your meds through the checker above

The bottom line

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

Acetyl-L-carnitine might be worth considering if you're dealing with age-related memory changes, Alzheimer disease, diabetic nerve pain, or depression—but check with your pharmacist first if you take blood thinners, antidepressants, migraine meds, or thyroid hormone. Long-term safety data is thin, so this is a short-term trial kind of supplement.

Talk it through with your doctor or pharmacist before you start.

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 Aug 23, 2013.

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 250 mg, straight from the product label.

Brand Klaire Labs
Barcode (UPC) 709616941102
Net contents 100 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Aug 23, 2013
DSLD ID 25343
Product type Amino Acid/protein
Supplement form Capsule
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years)
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 250 mg by Klaire Labs, 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
100
UPC/BARCODE
709616941102
IngredientAmount% DV
Acetyl-L-Carnitine250 mg--

Other ingredients: Vegetarian Capsule, L-Leucine, Silicon Dioxide, Cellulose

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.
Formulation

Free of the following common allergens: milk/casein, eggs, fish, shellfish, tree nuts, peanuts, wheat/gluten, corn, yeast, and soybeans. No sugar, magnesium stearate, maltodextrin, artificial sweeteners, colors, flavors, salicylates, or preservatives.

Precautions

Free of the following common allergens: milk/casein, eggs, fish, shellfish, tree nuts, peanuts, wheat/gluten, corn, yeast, and soybeans.

Do not use if full-bottle shrinkwrap is broken or missing.

KEEP OUT OF REACH OF CHILDREN.

General Statements

Formulated for the most sensitive individual.

This product was made in a GMP and ISO 9001:2008 registered facility.

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement take one capsule twice daily or as directed by a healthcare practitioner. Capsules may be pulled apart and nutrients taken separately.

General

V941-10 rev110024T

FDA Statement of Identity

AMINO ACID SUPPLEMENT

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

See for yourself

Acetyl L-Carnitine 250 mg by Klaire Labs label

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

Acetyl L-Carnitine 250 mg 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 250 mg by Klaire Labs

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 container100 Amounts shown are per serving.

Acetyl-L-Carnitine

Interacts with
203 drugs
250 mg per serving Form: Acetyl-L-Carnitine Hydrochloride

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 monograph & interactions

Other (inactive) ingredients: Vegetarian Capsule, L-Leucine, Silicon Dioxide, Cellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

Acetyl L-Carnitine 250 mg by Klaire Labs Drug Interactions

Want to check YOUR meds against Acetyl L-Carnitine 250 mg?

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 203

Individual Drug Interactions

The ingredients in Acetyl L-Carnitine 250 mg interact with 203 drugs. Click any drug to see the details.

1 of the 1 ingredient in Acetyl L-Carnitine 250 mg interact with drugs. Each result below shows which ingredient is responsible. Acetyl-L-Carnitine

Each ingredient & the kinds of drugs it affects

For each ingredient in Acetyl L-Carnitine 250 mg 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-Carnitine4 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 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Acetyl L-Carnitine 250 mg, from the product label.

Klaire Labs

See all Klaire Labs products
Name
ProThera, Inc.
City
Reno
State
NV
ZipCode
89521
Phone Number
888-488-2488
Pharmacist Counseling Corner

Acetyl L-Carnitine 250 mg by Klaire Labs: Common Questions

Does Acetyl L-Carnitine 250 mg by Klaire Labs interact with any medications?
Yes. Based on its ingredients, Acetyl L-Carnitine 250 mg 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 250 mg 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 in my body?
It's a compound your body makes naturally from carnitine, an amino acid. The evidence suggests it may help with memory and cognitive function as you age, and possibly with nerve pain from diabetes and depression—but the research isn't locked in yet.
Are there side effects I should know about?
The most common ones are agitation, dry mouth, headache, insomnia, and loss of appetite. Some people report nausea, vomiting, diarrhea, or constipation, though these aren't much more frequent than in people taking a placebo. One unusual effect: a fishy smell in urine, breath, or sweat.
Can I take this long-term?
Short-term use is generally well tolerated, but long-term safety isn't fully established. This isn't something you'd want to take indefinitely without checking in with your doctor about what we don't yet know.
Is it safe during pregnancy or while breastfeeding?
There isn't enough reliable data to say it's safe during pregnancy. Safety while breastfeeding is unknown, so avoiding it is the safer choice unless your doctor has a specific reason to recommend it.
What's in the capsule besides the active ingredient?
The capsule itself is vegetarian, and the other inactive ingredients are L-leucine, silicon dioxide, and cellulose. These are fillers and binding agents that help hold the supplement together.

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 250 mg label
Go deeper

The Full Monographs Behind Acetyl L-Carnitine 250 mg’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 250 mg'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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