Acetyl-L-carnitine
TL;DR
Acetylated form of L-carnitine that crosses the blood-brain barrier. Supports mitochondrial energy production in neurons. Evidence for neuropathy, cognitive decline, and depression.
Safety: Well-tolerated. GI discomfort possible. May cause restlessness/insomnia if taken late in day.
Cost: approximately $15-25/month.
Best for: Cognitive decline
What the research says
Multiple RCTs show modest benefit for MCI and age-related cognitive decline. Also studied for depression and diabetic neuropathy. Effects may take 3-6 months.
Small pilot studies suggest possible benefit for noise-induced tinnitus via cochlear mitochondrial support. Evidence is very preliminary.
Acetyl-L-carnitine on Amazon
*Link is just for your convenience - we do not make any fees
Safety & practical info
GI discomfort possible. May cause restlessness/insomnia if taken late in day.
Same interaction profile as L-carnitine. May increase agitation in some psychiatric conditions.
Moderate cost at therapeutic doses.
Sources for this page include published meta-analyses, systematic reviews, and NIH dietary supplement fact sheets. All claims reflect the evidence as of early 2026.
This is not medical advice. Consult your healthcare provider before starting any supplement, especially if you take medications.