Alpha-lipoic acid (ALA) is a synthetic version of lipoic acid, which helps cells make energy. It has antioxidant properties and may reduce inflammation. While ALA supplements are generally considered safe, clinical research is very limited particularly for cognition, and it has shown variable effects on patients with mild to moderate Alzheimer's disease.
No randomized controlled trials have examined whether ALA can prevent or treat dementia, though two clinical trials reported that ALA, in conjunction with other supplements, did not benefit patients with Alzheimer’s disease. Our search identified:
• 0 meta-analyses or systematic reviews
• 2 randomized controlled trials and 2 open-label (not placebo-controlled) studies in Alzheimer's patients
• 0 observational studies
• Multiple preclinical studies
Preclinical research suggests that ALA scavenges free radicals, reduces inflammation, and may protect brain cells from conditions such as stroke, multiple sclerosis, and Alzheimer's disease. Preclinical studies also indicate that ALA or a combination of ALA and regular exercise may improve certain aspects of learning and memory . However, no clinical studies suggest that ALA can prevent dementia or improve cognition.
In clinical trials, ALA treatment for mild cognitive impairment and Alzheimer's patients has shown mixed results. In one clinical trial, Alzheimer's patients' cognitive function worsened after 16 weeks of treatment with an antioxidant cocktail of ALA (900 mg), vitamin E, and vitamin C. Though the supplements reduced evidence of oxidative stress in the brain by 19 percent, they did not appear to help patients' cognition . In another clinical trial, Alzheimer's patients who took a combination of 600 mg of ALA with omega-3 fatty acids for one year showed less cognitive and functional decline . Two open-label pilot studies suggested that ALA, in addition to standard care, might benefit Alzheimer’s patients with diabetes or dementia patients .
Evidence from clinical trials suggests that ALA is generally safe for healthy individuals, although one clinical trial reported occasional minor stomach discomfort at high doses. Additional side effects may include nausea and skin rash. Allergic reactions can occur as can a potential lowering of blood sugar .
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
Alpha-lipoic acid is found in low amounts in foods such as spinach, broccoli, potatoes, carrots, beets, and red meat. ALA is also widely available as an over-the-counter supplement. There are no official recommended doses for ALA supplements, but clinical trials with Alzheimer's patients have used doses ranging from 600 to 900 mg/day for up to 2 years without reporting serious side effects.
Information including possible side effects at Drugs.com.
"Dietary Supplements: What You Need to Know," from the U.S. Food and Drug Administration (FDA)