Acetyl-L-Carnitine (ALCAR)

Evidence: ★★★☆☆ · Status: OTC Supplement

In plain English

A brain-penetrating form of carnitine that helps mitochondria burn fat for fuel and helps make the memory neurotransmitter acetylcholine. Studied mostly in nerve and age-related cognitive problems, not as a healthy-brain booster.

How it works

The acetylated form of L-carnitine that crosses the blood–brain barrier. It shuttles fatty acids into mitochondria for β-oxidation via the carnitine system (CRAT / CPT1) and donates acetyl groups for acetylcholine synthesis — supporting neuronal energy metabolism.

Molecular target & official sources

CRAT (NCBI Gene 1384) · Acetyl-L-carnitine (PubChem CID 7045767)

Protocol

500–2000 mg/day, usually split; take earlier in the day (can be mildly stimulating).

Bottom line

Best human evidence is for diabetic nerve pain and mild age-related cognitive decline — not a strongly proven nootropic for a healthy brain.

Helps with: Recover Faster · Focus & Cognition · Live Longer · Stress & Anxiety

The human evidence

RCTs support benefit in diabetic peripheral neuropathy and show modest cognitive benefit in mild cognitive impairment and early Alzheimer's; a meta-analysis suggested antidepressant effects, strongest in older adults. Distinct from plain L-carnitine (CID 10917) by actually reaching the brain.

Stacks with

Alpha-lipoic acid (classic mitochondrial pair), omega-3.

Shares a pathway — often paired with: Caffeine, Metformin, Statins (Atorvastatin/Rosuvastatin), Magnesium.

Availability & where to buy

Available over the counter. Widely available OTC — e.g. iHerb (ships worldwide); in Singapore also Guardian, Watsons, GNC, Shopee / Lazada. Look for a third-party-tested / GMP mark and check the dose per serving. Cheap (~S$15–25/month).

How it works: the Cholinergic pathway →