NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated July 13, 2026

L-Carnitine

Amino Acid ·Exploratory record · not publication-reviewed ·Updated July 13, 2026

Transports long-chain fatty acids into mitochondria for energy production.

Evidence tier
Moderate
Indexed sources
17 2013–2025
Interactions
0
Cost / month
$7.50 budget
Read the sources → Compare profiles
Publication status

Exploratory record, not a reviewed medical publication.

See the editorial and medical-review policies for the publication gate.

This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.

In short

What the research says.

A quick, data-only summary. The full evidence, dosing, and sources are below.

L-Carnitine is an amino acid most often used for fat metabolism, energy production, exercise recovery. NutriStack rates the overall evidence as moderate. A typical adult dose is 500-2,000 mg daily, commonly taken as l-carnitine l-tartrate (exercise) or acetyl-l-carnitine (brain). This profile indexes 17 sources.

What it's good for
  • Fat metabolism11
  • Energy production
  • Exercise recovery9,15
  • Heart health10
What to watch for
  • TMAO generation: L-carnitine is metabolized by gut bacteria to TMAO, associated with 62% increased all-cause mortality in meta-analyses
  • Nausea
  • Diarrhea
  • Hypothyroidism (may worsen)

The bottom line

Evidence rating moderate. Most-documented uses: fat metabolism, energy production, exercise recovery. 17 sources indexed (2013–2025), with 0 interaction records on file.

The science

How it works, mechanistically.

Core mechanism

Shuttles acyl groups across the inner mitochondrial membrane via the carnitine palmitoyltransferase (CPT) system, enabling beta-oxidation of fatty acids for ATP production.

Class
Amino Acid Derivative
Found in food
Red meat, Dairy, Fish
Low-status signs
Fatigue, Muscle weakness
Absorption
Water-soluble; take with food
Dosing

Dosing & protocol.

Common range
500-2,000 mg daily
Recommended form
L-Carnitine L-Tartrate (exercise) or Acetyl-L-Carnitine (brain)

Better absorbed with carbohydrates6,8

Cost

What it actually costs.

Real-world pricing across three quality tiers. Assumes L-Carnitine L-Tartrate.

BudgetBest value
$7.50 /mo
$0.25 per dose
Mid
$15.00 /mo
$0.50 per dose
Premium
$30.00 /mo
$1.00 per dose

Assumes 500-2,000 mg/day. Vendor basis: NOW/iHerb, Vitacost, BulkSupplements powder, and Amazon marketplace; tablets and liquid formats price higher. Updated 2026-05-28.

From food

The same dose, as food.

How much you'd eat to match a supplemental dose.

500-2,000 mg L-carnitine
About 4-8 ounces beef may provide roughly 100-300 mg, while lamb, pork, fish, chicken, and dairy provide smaller amounts; 500 mg usually requires large portions.

Red meat is the densest common food source, but supplement doses remain much more concentrated.

Safety

Full safety detail.

Side effects

  • TMAO generation: L-carnitine is metabolized by gut bacteria to TMAO, associated with 62% increased all-cause mortality in meta-analyses
  • Nausea
  • Diarrhea

Contraindications

  • Hypothyroidism (may worsen)
Sources

Sources, by evidence tier.

Numbered references. Citations throughout the page link here.

Meta-analyses & systematic reviews

13

Randomized controlled trials

1

Reviews & position papers

1

Reference material

2
FAQ

Common questions.

Quick answers about L-Carnitine, drawn from the data on this page.

What is L-Carnitine?

Transports long-chain fatty acids into mitochondria for energy production.

What is L-Carnitine used for?

Commonly cited benefits of L-Carnitine include: Fat metabolism; Energy production; Exercise recovery; Heart health. NutriStack rates the overall evidence as moderate.

What is a typical dose of L-Carnitine?

A typical adult dose of L-Carnitine is 500-2,000 mg daily. The commonly recommended form is L-Carnitine L-Tartrate (exercise) or Acetyl-L-Carnitine (brain). These are general ranges, not personalized advice; confirm the right dose with a clinician.

What are the side effects of L-Carnitine?

Reported side effects include tmao generation: l-carnitine is metabolized by gut bacteria to tmao, associated with 62% increased all-cause mortality in meta-analyses, nausea, diarrhea. This is educational information; check with a healthcare professional before use.

How strong is the evidence for L-Carnitine?

NutriStack rates this as Moderate, meaning several aligned RCTs or one large RCT plus supporting reviews. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.

Use this with your stack

L-Carnitine in NutriStack.

Add it to your stack, see how it interacts with everything else you take, and get a Stack Score that updates the moment it does.

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NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.