Alpha lipoic acid is a powerful natural antioxidant that protects blood vessels and other tissues from free radical damage. Numerous clinical trials have been conducted to examine its effects in people with type 2 diabetes. The strongest evidence for its beneficial effects comes from trials in subjects with diabetes-related nerve complications (neuropathy).^2,3 One placebo-controlled trial monitored 460 participants with type 1 or type 2 diabetes and mild to moderate polyneuropathy taking 600 mg per day of alpha lipoic acid or placebo for four years. Those taking alpha lipoic acid had significantly reduced symptoms and progression of neuropathy.⁴ In addition, clinical research suggests that alpha lipoic acid may improve insulin sensitivity, blood glucose control, and lipid metabolism, support weight loss, and reduce the impacts of diabetic complications such as retinopathy (damage to the retina in the eye), nephropathy (kidney dysfunction), and erectile dysfunction.^{5,6,7,8,9,10,11} Studies reporting benefits have generally used doses ranging from 600 to 1,200 mg of alpha lipoic acid per day.

Alpha lipoic acid is an important nutrient for mitochondrial function. It has antioxidant properties and can act as a reducer of oxidized forms of vitamins C and E. A number of placebo-controlled clinical trials have found that supplementing with 600 to 1,200 mg of alpha-lipoic acid per day can improve the symptoms of diabetic nerve damage (neuropathy).^12,13,14,15 Animal studies and early clinical research suggest alpha-lipoic acid may also help prevent diabetes-related damage to the small blood vessels and nerves in the eyes (diabetic retinopathy).^16,17

In a placebo-controlled trial, 360 people with obesity received 1,200 or 1,800 mg of alpha-lipoic acid per day or placebo for 20 weeks. The alpha-lipoic acid group experienced significantly greater weight and fat loss compared to the placebo group: the average weight loss was 6.1 pounds with 1,800 mg per day of alpha-lipoic acid, 3.3 pounds with 1,200 mg per day, and 2.1 pounds with placebo.¹⁸ A similar trial followed 81 participants with overweight and obesity for 24 weeks and found those taking 600 mg of alpha-lipoic acid per day experienced slightly more weight and percent body fat loss compared to those given placebo.¹⁹ Another placebo-controlled trial included 97 women with overweight or obesity who followed a calorie-restricted diet and were given 300 mg of alpha-lipoic acid or placebo daily for 10 weeks. The women who received alpha-lipoic acid lost an average of 3.3 pounds more than women who received a placebo.²⁰ An eight-week cross-over design trial found 1,200 mg of alpha-lipoic acid daily not only led to mild weight loss but also resulted in reduced waist circumference, suggesting it may reduce the most dangerous type of body fat.²¹ Meta-analysis of multiple randomized controlled trials has further added to the evidence that alpha-lipoic acid has a small effect on short-term weight loss.^22,23 Alpha-lipoic acid may even decrease weight gain associated with the use of antipsychotic medications. It is not clear how alpha-lipoic acid works, but some evidence suggests it may reduce inflammatory, appetite, and metabolic signaling.

 

In a small double-blind trial, supplementation with 600 mg of alpha-lipoic acid once a day for three months significantly reduced the frequency of migraine attacks. However, this improvement was not statistically significant when compared with the change in the placebo group.²⁴ Additional research is needed to determine whether alpha-lipoic acid is effective for preventing migraines.

 

Alpha lipoic acid (150 mg per day for one month) improves visual function in people with some types of glaucoma.²⁵

In a double-blind trial, supplementation with antioxidants for two months before and for six months during treatment with narrowband ultraviolet B light increased the effectiveness of the ultraviolet light therapy. The antioxidant supplement contained daily 100 mg of alpha-lipoic acid, 100 mg of vitamin C, 40 IU of vitamin E, and 100 mg of cysteine.²⁶