Dallas Clouatre, Ph.D.

Lipoic acid (alpha-lipoic acid) is one of the true stars in the world of antioxidants. Lipoic acid is often found under the name thioctic acid; when in the body, lipomide or lipoate. Lipoic acid not only is an antioxidant, but also a cofactor in the body’s production of energy as well as a nerve growth factor. Although it has many vitamin-like roles, it is not considered to be a vitamin because it is assumed that it can be synthesized by the body in small amounts from essential fatty acids. Lipoic acid is found in foods, such as liver and yeast, but there are no foods rich enough in this nutrient to serve as good sources.

The antioxidant qualities of lipoic acid make it a “universal” antioxidant. This coenzyme scavenges free radicals in both fat- and water-based environments in the body. Just as important as its direct antioxidant effects are the indirect ones. These effects include the regeneration of other antioxidants, such as vitamins C, E and coenzyme Q10. Lipoic acid increases the levels of intra-cellular glutathione and thereby enhances recovery from physical stress, such as in athletics, by reducing intra-cellular damage from free radicals. The impact on glutathione production is especially important for liver function. For this reason, in Europe lipoic acid is used in cases of alcohol, drug and virally-induced liver damage. Protection against the hypoxia (lack of oxygen in tissues) found with strokes has been demonstrated conclusively in animals.

Lipoic acid offers special benefits to diabetics. It enhances glucose uptake into muscle and brain cells, plus it inhibits glycosylation (the abnormal attachment of sugars to proteins). Lipoic acid has been used to improve diabetic neuropathy (nerve damage) and to reduce the pain associated with such nerve damage. Preliminary evidence, furthermore, indicates improvement in the visual function of some individuals taking 150 mg per day who suffer from glaucoma.

Athletes sometimes use nutrients that help to make cells more sensitive to insulin in order to increase the uptake and benefits of creatine. Lipoic acid has been suggested for this purpose and as an aid to reduce recovery time with workouts. Also, lipoic acid works synergistically with and helps to recycle other antioxidants, thus enhancing their effectiveness. Therefore it is a good idea to include a range of antioxidants in your daily supplements to take advantage of lipoic acid’s special properties.

Bruce Ames of UC Berkeley argues that human and animal trials show that mitochondrial oxidative decay, which is a major contributor to aging, can be ameliorated by the combination of acetyl-L-carnitine and lipoic acid. Together, these restore mitochondrial function, reduce levels of oxidants and mutagenic aldehydes, and increase ambulatory activity and cognition. In other words, supplementing with just the combination of these two nutrients alone may have a major impact on both the physical and the mental aspects of aging.

Neither animal nor human studies to date have any shown serious side effects with the ingestion of alpha-lipoic acid at levels that might reasonably be consumed. Side effects are very rare, but include allergic skin reactions and possible hypoglycemia in diabetics as a consequence of improved glucose utilization with high levels of intake. However, it is prudent that any group likely to be severely thiamine-deficient, for example, alcoholics, should take supplemental thiamine if alpha-lipoic acid is used regularly. Likewise, animal research suggests that supplementing biotin might be advisable if large amounts of lipoic acid are supplemented chronically. Except at the very low range of supplementation (50 mg/day) or under care of a doctor, alpha-lipoic acid not advised for use during pregnancy.

Lipoic acid is well absorbed via the stomach. It is a powerful antioxidant and free radical scavenger even when ingested in relatively small amounts. However, animal experiments have shown that this protective effect is highly dependent upon the timing and the form of administration. Lipoic acid is rapidly cleared from the blood by the liver and must be transformed into dihydrolipoic acid for maximal benefits both as an antioxidant and as a glucose disposal agent. Sustained release delivery may match better the known pharmacokinetics of alpha-lipoic acid than do the usual tablet and capsule delivery forms. Sustained release may be helpful to those who suffer from gastric distress from the very low pH (i.e., very acid quality) of alpha-lipoic acid when taken in regular dosage forms.

Fifty to one hundred milligrams supplemented once or twice per day is considered to be more than adequate for most purposes, with 300 mg daily viewed as the top end of a reasonable dosage range. Clinical studies with diabetics typically have employed 300 mg taken two or three times per day.

Dallas Clouatre, Ph.D., is a Jarrow Formulas consultant based in Santa Monica, California. He is a prominent industry consultant in the US, Europe, and Asia, and is a sought-after speaker and spokesperson. He earned his A.B. from Stanford and his Ph.D. in European Intellectual History from the University of California at Berkeley. A member of the American College of Nutrition, he is a regular contributor to various industry publications. He is the author of numerous books, including FAQ: All About Grapeseed Extract, SAM-e: The Ultimate Methyl Donor, Anti-Fat Nutrients (3rd edition), and The Prostrate Cancer Miracle.

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Selected References

Packer L, et al. Alpha-lipoic acid as a biological antioxidant. Free Radic Biol Med 1995;19:227–50.

Kagan V, et al. Antioxidant action of thioctic acid and dihydrolipoic acid. Free Radic Biol Med 1990;9S:15.

Lykkesfeldt J, et al. Age-associated decline in ascorbic acid concentration, recycling, and biosynthesis in rat hepatocytes—reversal with (R)-alpha-lipoic acid supplementation. FASEB J 1998;12:1183–9.

Kagan VE, et al. Recycling of vitamin E in human low density lipoproteins. Journal of Lipid Research 1992;33:385-397

Gotz ME, et al. Effect of lipoic acid on redox state of coenzyme Q in mice treated with 1-methy-l-4-phenyl-1,2,3,4- tetrahydropyridine and diethyldithiocarbamate. European Journal of Pharmacology 1994;266: 291-300.

Busse E, Zimmer G, Schorpohl B, et al. Influence of alpha-lipoic acid on intracellular glutathione in vitro and in vivo. Arzneimittelforschung 1992;42:829–31.

Jacob S, et al. Enhancement of glucose disposal in patients with type 2 diabetes by alpha-lipoic acid. Arzneimittel-Forschung 1995:45:872-874

Barbiroli B, et al. Lipoic (thioctic acid) increases brain energy availability and skeletal muscle performance as shown by in vivo 31P-MRS in a patient with mitochondrial cytopathy. Journal of Neurology 1995:242:472-477.

Filina AA, et al. Lipoic acid as a means of metabolic therapy of open-angle glaucoma. Vestn Oftalmol 1995;111:6–8.

Wolz P, Krieglstein J. Neuroprotective effects of alpha-lipoic acid and its enantiomers demonstrated in rodent models of focal cerebral ischemia. Neuropharmacology, 1996 March;35(3):369-75.

Shih JC. Atherosclerosis in Japanese quail and the effect of lipoic acid. Fed Proc 1983 May;42:2494-7.

Ames BN. The metabolic tune-up: metabolic harmony and disease prevention. J Nutr. 2003 May;133(5):1544S-8S.

Zempleni J, Trusty TA, Mock DM. Lipoic acid reduces the activities of biotin-dependent carboxylases in rat liver. J Nutr 1997;127:1776–81.