Alpha Lipoic Acid

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). 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).

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). 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. 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. Studies reporting benefits have generally used doses ranging from 600 to 1,200 mg of alpha lipoic acid per day.

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. Additional research is needed to determine whether alpha-lipoic acid is effective for preventing migraines.

Several controlled trials have found intravenous alpha-lipoic acid can reduce symptoms of diabetic peripheral neuropathy; however, the effect of oral alpha-lipoic acid is still unclear. Preliminary research has suggested the benefits of supplementing with oral alpha-lipoic acid may be too small to be meaningful, yet one uncontrolled trial found 600 mg of lipoic acid daily for 40 days relieved symptoms and improved quality of life in people with painful diabetic peripheral neuropathy. Other clinical trials have shown alpha-lipoic acid may enhance the efficacy of conventional therapies. A meta-analysis of 20 studies with a combined total of 1,894 subjects with diabetic neuropathy found epalrestat plus alpha-lipoic acid was more effective for reducing symptoms and improving nerve function than either therapy alone. Other meta-analyses have had similar findings.

In a placebo-controlled trial that included data from 70 cancer patients being treated with cisplatin or oxaliplatin, taking 600 mg of lipoic acid three times daily for 24 weeks had no impact on neuropathy. A preliminary trial in multiple myeloma patients being treated with bortezomib, a combination of 600 mg alpha-lipoic acid plus 400 mg of docosahexaenoic acid (DHA), 60 mg of vitamin C, and 10 mg (15 IU) of vitamin E twice daily for six months appeared to prevent the onset and worsening of neuropathic pain. More research is needed to determine whether alpha-lipoic acid can protect nerves against damage induced by certain chemotherapy agents.

In a double-blind trial, obese people who supplemented with alpha-lipoic acid (1,200 or 1,800 mg per day for 20 weeks) resulted in a statistically significant weight loss, compared with a placebo. The amount of weight lost 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. The weight loss was due primarily to a loss of fat mass, as opposed to muscle mass. It is not clear how alpha-lipoic acid works, but it may work by increasing the conversion of fuel to energy in the body. In another double-blind trial, supplementation with alpha-lipoic acid (300 mg per day for 10 weeks) enhanced weight loss in overweight and obese women who were consuming a low-calorie diet. Women who received alpha-lipoic acid lost an average of 3.3 pounds more than women who received a placebo.

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.

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

A potent antioxidant combination may protect the liver from damage in people with hepatitis C, possibly decreasing the necessity for a liver transplant. In a preliminary trial, three people with liver cirrhosis and esophageal varices (dilated veins in the esophagus that can rupture and cause fatal bleeding) caused by hepatitis C received a combination of Alpha lipoic acid (300 mg twice daily), silymarin (from milk thistle; 300 mg three times daily), and selenium (selenomethionine; 200 mcg twice daily). After five to eight months of therapy that included other "supportive supplements," such as vitamin C and B vitamins, all three people had significant improvements in their liver function and overall health. Larger clinical trials are needed to confirm these promising preliminary results.