Skip to main content

Verified by Psychology Today


Acetyl-l-carnitine: Important for Mental Health

An amino acid for treating depressed mood, cognitive decline, and dementia.

ALC is an important supplement for mental health care

The amino acid acetyl-l-carnitine (ALC) occurs naturally in the brain and liver. Placebo-controlled studies have reported beneficial effects of ALC supplementation in individuals diagnosed with depressed mood and dementia. These findings are important in view of the limited effectiveness and safety problems of conventional prescription anti-depressants and medications used to treat dementia.

Neuroprotective effects

Placebo-controlled studies have investigated ALC supplementation in severely depressed individuals, elderly depressed patients, and depressed patients with dementia. ALC is known to have important general neuroprotective effects including increased mitochondrial energy production.

Neuroprotective effects of ALC may help improve depressed mood and reduce the severity of cognitive impairments associated with normal aging, dementia, or traumatic brain injury.

Anti-depressant benefits

A review of placebo-controlled studies on ALC in depressed mood showed that ALC was more effective than a placebo for moderately depressed mood and was just as effective and had fewer side effects compared to the antidepressants fluoxetine (Prozac) and amisulpride (Solian). A typical dose of ALC that has antidepressant effects is 500 mg four times daily for a total of 2gm/day.

Cognitive decline and dementia

ALC is widely used to treat cognitive impairments related to dementia and other neurodegenerative disorders; however, findings are inconsistent. In a two-month placebo-controlled trial, depressed patients with dementia randomized to 3 g per day of ALC experienced significantly greater improvements in mood and global cognitive functioning than the placebo group. Findings of many placebo-controlled studies show that doses of ALC between 1,500 and 3,000 mg per day improve overall performance on tests of reaction time, memory, and cognitive performance in patients diagnosed with dementia and may slow the rate of progression of cognitive impairment. A systematic review of 11 randomized placebo-controlled studies on ALC in patients diagnosed with dementia confirmed significant positive effects on memory and overall cognitive functioning 12 weeks and 24 weeks after starting treatment. However, improvements in functioning were not sustained at one year with continued treatment.

ALC may be beneficial in early onset dementia

Younger individuals experiencing early onset (i.e., presenile) dementia may benefit from supplementation with ALC more than older individuals. For unclear reasons, 62 years may be the “optimal age” beyond which ALC loses much of its cognitive-enhancing effects.

ALC may reduce age-related cognitive decline in healthy elderly individuals

Findings of placebo-controlled studies suggest that ALC taken at doses between 1.5 and 3 g per day (dived into three or four doses) improve normal age-related symptoms of cognitive decline in healthy elderly individuals who are not demented as well as in depressed individuals who experience problems with memory related to depressed mood.

ALC may improve cognitive functioning in alcoholics after they stop drinking

There is preliminary evidence that ALC taken at a dose of 2 g per day improves memory and word recall in cognitively impaired abstinent alcoholics. ALC is generally well tolerated and may be safely used in combination with conventional antidepressants and anti-dementia medications including cholinesterase inhibitors.


The Integrative Mental Health Solution, by James Lake MD

About the Author
James Lake, MD

James Lake, M.D., a clinical assistant professor at the University of Arizona College of Medicine, works to transform mental health care through the evidence-based uses of alternative therapies.

More from James Lake, MD
More from Psychology Today
More from James Lake, MD
More from Psychology Today