⚡ L-carnitine (ALCAR, LCLT): fat burning, brain, heart
How the carnitine "shuttle" helps turn fat into energy
L-carnitine is an amino-acid-like substance that plays a key role in energy metabolism. Its main function is to transport fatty acids into mitochondria, where they are converted into energy (ATP). Without carnitine, cells cannot efficiently use fat as fuel. Let's look at supplement forms and their benefits.
What is L-carnitine
L-carnitine participates in the so-called carnitine shuttle — the mechanism that carries long-chain fatty acids across the mitochondrial membrane. Inside the mitochondria, these acids are oxidized to produce energy.
Forms: ALCAR and LCLT
| Form | Full name | Feature |
|---|---|---|
| L-carnitine | L-carnitine | Basic form, fat transport |
| ALCAR | Acetyl-L-carnitine | Crosses into the brain, nootropic |
| LCLT | L-carnitine L-tartrate | Good bioavailability, popular in sports |
ALCAR (acetyl-L-carnitine) crosses the blood-brain barrier better, so it is more often used for brain support. LCLT (tartrate) is widely used in sports supplements for recovery.
Benefits for the body
Fat burning and energy
L-carnitine helps cells use fat for energy, which can support fat oxidation during training and reduce fatigue.
Brain
ALCAR is studied for supporting cognitive function, memory and energy levels in the elderly. It is involved in producing acetylcholine — a memory neurotransmitter.
Heart
The heart muscle actively uses fatty acids, so L-carnitine is important for its energy supply. Some studies show benefits for heart weakness and fatigue.
Food sources
| Food | Carnitine content | Comment |
|---|---|---|
| Beef (cooked) | ~80–95 mg/100 g | One of the best sources |
| Chicken | ~3–5 mg/100 g | Less than in red meat |
| Fish | ~5 mg/100 g | Moderate amount |
| Milk | ~3 mg/100 ml | Small amount |
The body also synthesizes carnitine from the amino acids lysine and methionine (with vitamin C, iron and B6). Vegans and vegetarians often need more attention here, as plant foods are poor in carnitine.
Dosage and use
| Form | Typical dose | When to take |
|---|---|---|
| L-carnitine / LCLT | 1–2 g a day | Before/after training or with food |
| ALCAR | 600–1500 mg a day | In the morning, for the brain |
What is L-carnitine?
An amino-acid-like substance that transports fatty acids into mitochondria to produce energy.
How is ALCAR different from regular carnitine?
ALCAR (acetyl-L-carnitine) crosses into the brain better and is more often used for cognitive support.
What is LCLT?
L-carnitine L-tartrate — a form with good bioavailability, popular in sports supplements.
Does carnitine help burn fat?
It helps deliver fatty acids into mitochondria for energy, supporting fat oxidation during exertion.
Which foods have carnitine?
Most in red meat (beef), less in chicken, fish and milk.
Do vegans need carnitine?
Vegans should pay attention, as plant foods are poor in carnitine and synthesis is limited.
What is the optimal dose?
Usually 1–2 g a day for L-carnitine and 600–1500 mg for ALCAR.
Does carnitine help the brain?
ALCAR is studied for supporting memory and cognitive function in the elderly.
What are the side effects?
At high doses, GI upset and a "fishy" smell from the mouth are possible.
When to take carnitine?
L-carnitine before/after training or with food, ALCAR in the morning for energy and the brain.