L-Carnitine
Made from the amino acids lysine and methionine and found mostly in red meat; it carries fatty acids into mitochondria to be burned.
An amino-acid derivative; levocarnitine (Carnitor) is an approved drug for carnitine deficiency, oral forms are supplements.
Used for
- Fat loss support
- Energy and exercise recovery
- Male fertility (sperm motility)
- Low energy and libido in older men
- Carnitine deficiency and dialysis (approved use)
How it works
The shuttle that moves long-chain fatty acids into mitochondria. Muscle stores rise only slowly by mouth (little is absorbed and uptake needs insulin), which is why some inject it.
Half-life: About 17 hours (IV levocarnitine)
What the research shows
- A meta-analysis of 37 randomized trials found about 1.2 kg more weight loss than placebo, mostly in adults with overweight; results were larger at around 2 g a day.
- In a 24-week trial, 2 g twice a day taken with 80 g of carbohydrate raised muscle carnitine about 20%, spared muscle glycogen and made hard exercise feel easier; without the carbohydrate, muscle levels did not rise.
- In aging men, 6 months of propionyl- plus acetyl-L-carnitine (2 g each daily) improved erectile function and mood about as much as testosterone, and fatigue more.
- In men with low sperm motility, L-carnitine 2 g plus acetyl-L-carnitine 1 g daily for 6 months improved motility, mainly in those with the lowest starting values.
- Gut bacteria turn carnitine into TMAO, which promoted atherosclerosis in mice and was linked to heart disease in people.
Dosing
Dosing isn’t listed on the public site. In the app, each published option is shown with its source (a drug label, a clinical guideline, a trial or community reports) and can be turned into a protocol you review.
Work out the units to draw for your vial →Side effects
- Fishy body odor at higher doses
- Nausea, cramps or diarrhea (oral)
- Sore injection site
Cautions
- Seizures have been reported, in people with and without a seizure history.
- May blunt thyroid hormone action: take care with hypothyroidism or thyroid medication.
- Can raise INR on warfarin.
- Raises TMAO, a marker linked to heart disease; the clinical meaning for supplement users is unsettled.
Storage
Unmixed powder: freezer or fridge, away from light.
Once mixed with bacteriostatic water: fridge; the common rule is to use it within 28 days.
There is no label or published stability data for this one, so treat these as habits, not limits.
More in Weight & metabolic
Reference only, not medical advice. Written for this app from the cited research. Doses marked community-reported are not from trials.