Acetyl-L-Carnitine

What it does

Acetyl-L-carnitine (ALCAR) shuttles fatty acids into mitochondria and supports acetylcholine synthesis. It has meta-analysis support for depression and mild cognitive impairment, mostly in older adults, and RCT data for fatigue and diabetic neuropathy.

What the research says

• Reduced depressive symptoms across 12 RCTs

  Evidence: moderate. Veronese et al. 2018 (Psychosomatic Medicine, 791 participants): large pooled effect (SMD -1.10), comparable to antidepressants with fewer side effects; strongest in adults over 65. Not a substitute for prescribed treatment.

• Slowed cognitive decline in mild cognitive impairment and early Alzheimer's

  Evidence: emerging. 2003 meta-analysis of 21 RCTs (1,479 participants): modest but significant benefit on memory, attention, and intellectual function; a large 1-year Alzheimer's trial was negative

• Improved fatigue in a small chronic-fatigue trial

  Evidence: emerging. 36-person randomized crossover: 1 g twice daily for 3 months beat amantadine on brain function and was better tolerated

• Improved diabetic peripheral neuropathy symptoms

  Evidence: moderate. De Grandis & Minardi 2002 (n=333, 52 weeks) and Sima 2005 (n=1,257, two RCTs) reported less neuropathic pain and better vibration perception

Replicated signals across independent meta-analyses in depression, MCI, and neuropathy, with good tolerability. Many trials are small or old, effects are modest, and it is not an Alzheimer's treatment.

Is it worth it?

One of the better evidence-per-dollar options in this batch for older adults with low mood, fatigue, or neuropathy. Depression is a medical condition: use with a clinician.