Acetyl-L-Carnitine
A form of carnitine studied for energy metabolism and cognition.
Want to try Acetyl-L-Carnitine?
See our pick — chosen for form and dose — in our professional dispensary. Please read Safety & interactions first.
Buy on Fullscript →You'll create a free Fullscript account and check out through our professional dispensary — 20% off retail.
We may earn a commission on Fullscript purchases, at no extra cost to you. Affiliate Disclosure
What it is
Acetyl-L-carnitine is a form of the amino-acid derivative carnitine that helps shuttle fatty acids into cells to make energy and can cross into the brain, underlying its cognitive interest.
How it works
Acetyl-L-carnitine (ALCAR) helps shuttle fatty acids into the mitochondria to be burned for energy, and unlike plain carnitine it crosses into the brain, where it's studied for cognition and mood. These roles underlie its use for energy and mental function.
What it's been studied for
Taken to support energy metabolism, cognition, and, in some contexts, nerve comfort.
What the evidence shows
There's some supportive evidence in older adults and specific clinical situations (such as age-related cognitive complaints and certain neuropathies), but results in healthy people are mixed. Reasonable but not definitive.
Who should consider it
It's used for energy metabolism, cognition, and, in some clinical contexts, nerve comfort. Evidence is more supportive in older adults and specific conditions than in healthy young people. It's often chosen by those wanting a brain-oriented carnitine.
Amounts commonly studied
Studies commonly use around 500-2,000 mg per day.
How to take it
Studies commonly use around 500-2,000 mg per day. It can be taken with or without food; some find it activating, so earlier in the day may be better. ALCAR crosses into the brain better than plain L-carnitine.
Forms & absorption
Acetyl-L-carnitine (ALCAR) crosses into the brain better than plain L-carnitine, which is used more for physical/heart contexts.
Food sources
Carnitine is found mainly in red meat and, to a lesser degree, fish, poultry, and dairy; the body also makes its own.
Safety & interactions
Generally well tolerated; can cause digestive upset or restlessness. May interact with thyroid medication and blood thinners.
Myths & what it won't do
Myth: ALCAR is a proven brain booster for everyone. Reality: evidence is more supportive in older adults and specific conditions, and mixed in healthy people. Myth: it's a strong fat-burner. Reality: carnitine supplements haven't shown reliable fat-loss effects in well-nourished people.
Common questions
- ALCAR or L-carnitine?
- ALCAR crosses into the brain better and is used more for cognition; plain L-carnitine is used more for physical and heart-related contexts.
- Does it help energy or focus?
- There's some evidence in older adults and certain conditions, but results in healthy people are mixed.
- Any interactions?
- It may interact with thyroid medication and blood thinners — check with your provider if relevant.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on Acetyl-L-Carnitine
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- 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(2):61-71. View study →Note: Pooled trials found a modest benefit in mild cognitive impairment and mild Alzheimer's disease; it didn't study healthy people.