Alpha Lipoic Acid Supplements Review
Initial Posting: 12/3/16 Last Update: 4/30/20
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What It Is:
- What is it? Alpha-lipoic acid (or lipoic acid) assists in converting glucose into energy (See What It Is). A healthy body naturally produces enough alpha-lipoic acid but supplementation may help in certain situations.
- What does it do? Alpha-lipoic acid supplements may improve insulin sensitivity and blood sugar control, as well as reduce symptoms of peripheral neuropathy in people with type 2 diabetes. It may also increase weight and fat loss when combined with a low-calorie diet (See What It Does).
- Which form? Supplements contain synthetic versions of the naturally occurring form of alpha-lipoic acid (the R-isomer) or, more commonly, a mixture the R- and S-isomer forms. The R-isomer is the more active of the two isomers, however, only mixed forms have been studied for efficacy and side-effects in clinical trials and are generally much less expensive than R-isomer-only products. (See What to Consider When Buying).
- How much to take? The typical dose for treating diabetes, peripheral neuropathy associated with diabetes, and cardiac autonomic neuropathy is 200 to 400, taken 3 times daily (for a total daily dose ranging from 600 mg to 1,200 mg). For weight loss, 100 mg alpha-lipoic acid (taken three times per day with meals), along with a reduced-calorie diet, has shown to be beneficial. For use as a general antioxidant, a lower dose (20 to 50 mg daily) is commonly recommended (although there is no evidence this offers any health benefit). You may be able to halve the dose when using the R-isomer-only form (See What to Consider When Using).
- Best choice? Many products passed our tests of quality (See What CL Found). Among Approved products, ConsumerLab.com identified several which represented its Top Picks.
- Cautions: Side effects such as skin rash and nausea have been reported. Alpha lipoic acid may also contribute to acid reflux, as it is an acid. Because alpha-lipoic acid may help control blood sugar in diabetics, adjustments may be needed to anti-diabetic medication when using alpha-lipoic acid. Alpha-lipoic acid may interfere with thyroid function, medication and diagnostic tests (See Concerns and Cautions).
Alpha-lipoic acid (or lipoic acid) is naturally produced in the body, assisting in the conversion of glucose to energy. It also acts as an antioxidant, able to neutralize harmful chemicals known as free radicals. It can function in both water and fat, as opposed to the antioxidants vitamin E (which works only in fat) and vitamin C (which works only in water). It may also be able to regenerate these other antioxidants after they have neutralized free radicals.
The naturally occurring form of alpha-lipoic acid is the R-isomer, which can also be produced synthetically. If a product does not specifically list the R-isomer-only form, it likely contains a synthetic 50/50 mixture (also called a "racemic" or "rac" mixture) of the R- and S-forms of alpha-lipoic acid. (See "Mixed form vs. R-isomer form.) The S-form itself is likely neutral (inactive) (Kilic, Biochem Mol Biol Int 1995) although there is a patent on the S-form as an analgesic.
What It Does:
As an oral supplement alpha-lipoic acid seems to reduce symptoms of peripheral neuropathy in diabetes patients, reducing symptoms such as burning, pain, numbness, and prickling of the feet and legs as well as improving sensation. There is evidence that alpha-lipoic acid supplements may also help diabetic patients by lessening damage of the heart, kidneys and small blood vessels.
Taking alpha-lipoic acid (300 to 1,200 mg daily) also seems to improve insulin sensitivity and blood sugar control in people with type 2 diabetes, although it may only slightly reduce levels of glycosylated hemoglobin (HbA1c) according to results of 6-month study comparing alpha-lipoic acid to placebo (Porasuphatana, Asia Pac J Clin Nutr 2012).
Alpha-lipoic acid was shown to increase weight and fat loss in a study of 77 healthy, but sedentary, overweight/obese women (ages 20 to 50) on a reduced-calorie diet. Those who took alpha-lipoic acid (300 mg per day), or a combination of alpha-lipoic acid and the omega-3 fatty acid EPA (1,300 mg per day) for 10 weeks lost significantly more weight (an average of 15 lbs. and 14 lbs., respectively), compared to those who took EPA only, or a placebo (average weight loss of 12 lbs. and 11.5 lbs., respectively) (Huerta, Obesity 2015). The women who took alpha-lipoic acid alone or with EPA also lost significantly more body fat than those who took EPA only, or a placebo. The alpha-lipoic acid was taken as a single 100 mg capsule (Nature's Bounty) with breakfast, lunch and dinner. The EPA, (433.3 mg EPA (Solutex) was also taken at those times. Larger and longer studies are needed to confirm these effects. Some preliminary evidence suggests alpha-lipoic acid may aid weight loss by promoting the breakdown of fat and inhibiting the formation of new fat cells (Fernandez-Galilea, J Lipid Res 2012; Carrier, J Human Nutr Food Sci 2013).
A placebo-controlled, 1-year pilot study of 34 adults with mild to moderate impairment from Alzheimer's disease found that alpha-lipoic acid and fish oil slowed the decline in subjects' cognitive functioning. The combination also slowed the decline in subjects' ability to perform daily activities, as did fish oil alone, but not alpha-lipoic acid alone. The participants normally ate fish no more than once per week and most continued to take Alzheimer's medications. A capsule of alpha-lipoic acid (600 mg) was taken each morning along with 2 fish oil capsules (each containing 1 gram of fish oil providing 325 mg EPA and 225 mg DHA in the triglyceride form). Another fish oil capsule was taken with lunch (Shinto, J Alzheimers Dis 2014). Although earlier studies have not shown a benefit with omega-3 fatty acids in Alzheimer's disease, this study differed in that the fish oil had a high ratio of EPA to DHA.
Although there is research suggesting additional potential uses of alpha-lipoic acid, there are few meaningful studies in humans to support these uses. Preliminary studies suggest that alpha-lipoic acid might help prevent or treat a myriad of conditions including age-related hearing loss, glaucoma, cancer, and cataracts. Some research suggested that alpha-lipoic acid might be helpful in treating burning mouth syndrome (BMS), a condition characterized by unexplained scalding sensations in the mouth, but a later study (using 400 mg of alpha-lipoic acid for 8 weeks) found no benefit compared to placebo (Carbone, Eur J Pain 2009).
The antioxidant effects of alpha-lipoic acid might provide protection in a number of other conditions including cerebral ischemia, other causes of damage to brain or neural tissue, mitochondrial dysfunction, liver disease, and aminoglycoside-induced cochlear damage. Additionally, the antioxidant effect may be useful in heavy metal and chemical poisoning as well as radiation exposure.
Preliminary research also suggests that alpha-lipoic acid may counteract neuropathy associated with some chemotherapy. Alpha-lipoic acid inhibits replication of the human immunodeficiency virus (HIV) in vitro and, in AIDS patients, might improve blood antioxidant status and increase T-helper lymphocytes and T-helper to T-helper suppressor cell ratio.
Alpha-lipoic acid has been touted for improving the appearance of aging skin, but there is no clinical evidence that alpha-lipoic acid taken orally (as with a supplement) has such an effect. Some benefit, however, was reported with an alpha-lipoic acid cream (5% alpha lipoic acid that included small amounts of CoQ10 and acetyl-L-carnitine) (Beitner, Br J Derm 2003). Applied daily for 12 weeks to the faces of women age 40 to 75, the cream resulted in a 51% reduction in skin roughness, although the same cream without alpha-lipoic acid resulted in 41% reduction. Interestingly, the 2003 article reporting this study noted that a longer study was in progress, although results do not appear to have been published.
Quality Concerns and What CL Tested for:
Neither the FDA nor any other federal or state agency routinely tests alpha-lipoic acid supplements for quality prior to sale. Prior studies by ConsumerLab.com have shown a small percentage of alpha-lipoic acid supplements to lack the full amount of this ingredient. ConsumerLab.com, as part of its mission to independently evaluate products that affect health, wellness, and nutrition, purchased several dietary supplements sold in the U.S. claiming to contain alpha-lipoic acid. These were tested for their amounts of alpha-lipoic acid and, if they contained herbal ingredients, were also tested for potential contamination with heavy metals (lead, cadmium, and arsenic). Standard tablets and caplets were also tested for their ability to properly disintegrate ("break apart") as needed for absorption.