This information is for research and educational purposes only. No medical recommendations. Products are not approved for human use. For health questions, consult a doctor.

Lexicon

Weight management

L-Carnitine

The shuttle that moves fatty acids into the mitochondria - a classic in energy and fat metabolism.

1 min read 1 sources Titration Updated June 2026
Class
Amino acid derivative (carnitine)
Use
Subcutaneous or intramuscular
Half-life
several hours
Status
Endogenous; IV infusions restricted in sport

Getting started

Typical dosing (research context)

Per-week figures in mg, subcutaneous or intramuscular. Well tolerated.

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What is L-Carnitine?

L-Carnitine is an endogenous amino acid derivative that shuttles fatty acids into the mitochondria, where they are burned for energy. In research and fitness contexts the injectable form is used for fat metabolism and endurance.

This information is for research and educational purposes only. No medical advice.

How it works

Without carnitine, long-chain fatty acids cannot cross the inner mitochondrial membrane. L-Carnitine is the shuttle for that - more available carnitine can support fatty acid oxidation. Injected, it bypasses the limited oral uptake.

Use and dosing

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What the research shows

Wall et al. (J Physiol, 2011) showed that chronic L-carnitine intake together with carbohydrate raises muscle carnitine content and alters muscle metabolism during exercise - less glycogen use at moderate intensity. Data on pure fat-loss effects in humans are mixed.

Side effects

  • Overall very well tolerated.
  • Occasional fishy body odor at high doses (TMAO formation).
  • Mild gastrointestinal discomfort possible.

Storage

Store at room temperature, protected from light - no fridge needed. Out of reach of children.

Evidence

Sources

  1. 1 Chronic oral L-carnitine and carbohydrate ingestion increases muscle carnitine content and alters muscle fuel metabolism in humans. Wall et al., J Physiol, 2011

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