Alpha-lipoic acid (ALA; also known as ‘thioctic acid’) role in the body

Alpha-lipoic acid (ALA; also known as ‘thioctic acid’) is a substance made by cells of many kinds — bacterial, plant, and animal. There are two forms of ALA: R-ALA and S-ALA — the R-form is the one found in nature; the S-form results from synthetic production of ALA in which both forms are made in equal amounts. Supplements are available containing either the R-form alone or a 50:50 mixture of R- and S-.

ALA’s role in the body

ALA serves as a cofactor in several biochemical processes in the body, including the process by which energy is extracted from carbohydrates (sugars).1

ALA is also an antioxidant that neutralizes several kinds of oxygen radicals and related reactive molecules, including hydroxyl, peroxyl and superoxide radicals, singlet oxygen, hydrogen peroxide, hypochlorous acid, peroxynitrite, and nitric oxide. Several of the body’s other antioxidants can be regenerated by ALA: vitamins C and E and glutathione.2 These antioxidant properties make ALA nature’s most powerful defense against the ravages of ‘reactive oxygen species’ (ROS).


Many good review articles about ALA are available, but most of them are under the control of unscrupulous scientific journals which charge outrageous fees to read them. Of the reviews freely accessible on the Internet, we recommend the Wikipedia article1, the review on ALA and cardiovascular disease by Wollin and Jones2, the review on ALA and exercise by Sen and Packer,3 all of which are somewhat technical but contain many passages useful and interesting to non-technical readers. The review on ALA and peripheral neuropathy by Head4 and the excellent review by Kidd5 on neurodegeneration, dementia, and aging are considerably less technical.

What we can’t tell you

In the U.S. and some other industrialized countries, government agencies like the U.S. Food and Drug Administration have adopted censorship as a method for intensifying their control over the supplement industry and its customers. Thus, FDA regulations prohibit us from telling you that any of our products are effective as medical treatments, even if they are, in fact, effective.

Accordingly, we will limit our discussion of Alpha-Lipoic Acid to a brief summary of relevant research, and let you draw your own conclusions about what medical conditions it may be effective in treating.

ALA has been of great interest to medical biologists since it was discovered in the 1950s. Nearly 2500 scientific articles that deal in some way with this substance have appeared since then, and numerous clinical trials have been conducted to test its effects on various medical conditions. As a result of this attention, the list of conditions for which ALA has been successfully applied is a long one, and includes:

  • Aging6,7,8,9,10,11,12,13
  • Insulin resistance14,15
  • Metabolic syndrome16
  • Diabetes17,18,19,20
  • Diabetic neuropathy21,22,23
  • Diabetic retinopathy24
  • Peripheral neuropathy4
  • Cancer25,26,27
  • DNA damage28,11
  • Neurological disorders29,30: memory,31 learning,32 dementia,33 Alzheimer’s34,35,36, Parkinson’s,29,37 Huntington’s38, ALS39
  • Burning mouth syndrome40,41
  • Cardiovascular disease2
  • Atherosclerosis19
  • Hypertension42,43
  • Vascular flexibility and function20,44,9
  • HIV45,46
  • Multiple sclerosis47
  • Chronic fatigue syndrome48
  • Cataracts49
  • Copper toxicity50
  • Lead toxicity51
  • Iron depletion52,53,54
  • Exercise55,3
  • Altered taste perception56
  • Pigmentation,57 skin bleaching58
  • Cell signalling59
  • Down’s Syndrome5

Let us look at several of these applications in a bit more detail.

Aging may be slowed by ALA

Evidence that ALA interferes with the aging process comes from lab experiments of several kinds:

  • ALA decreases intracellular build-up of lipofuscin (a granular debris that is considered to be a fundamental cause or symptom of aging).10
  • It prevents oxidative damage to cells’ mitochondria (energy extractors) and other structures.8,12
  • ALA improves brain function in aging rats by improving the levels of neurotransmitters.30
  • ALA extends the lifespan in roundworms (a favorite test animal for aging research).13
  • It restores vascular function in aged rats to conditions usually seen in younger animals.44
Neuropathy and retinopathy reduction by ALA

Many studies have been conducted to test ALA on diabetes-related neurological conditions, such as neuropathy4 and retinopathy.60 These studies have utilized tissue culture,24 lab animals,61 and humans.23 Many of the older clinical studies used intravenous injections of ALA solutions; while these experiments have generally shown significant benefits, they are essentially useless as clinical trials since daily intravenous treatments are impractical in most cases. The research money would have been better spent on studying oral ALA treatments.

Fortunately, more recent studies have tended to use orally dosed ALA — and have also shown significant benefits.

  • Oral treatment for 4-7 months tends to reduce neuropathic deficits.22
  • Oral treatment with ALA improved neuropathic symptoms and deficits in a study of 181 diabetic patients who received once-daily oral doses of 600 mg, 1,200 mg, or 1,800 mg of ALA or placebo for 5 weeks.21,23
ALA for other neurological disorders

Dysregulation of energy production, and inadequate suppression of free radical damage (‘oxidative stress’), have been implicated as promoters of conditions such as Alzheimer’s, Parkinson’s37, Huntington’s, cognitive aging, and various other neurological and neuromuscular diseases.29 Experiments in tissue culture, lab animals, and in humans have provided evidence that ALA can counteract the promoters of these ailments and reverse their symptoms:

  • In mice with a genetic predisposition to develop extreme Alzheimer’s symptoms, treatment with ALA reversed oxidative stress and improved cognition.31
  • ALA and its derivatives “improve the age-associated decline of memory”.8
  • ALA produced significant increases in survival in transgenic mouse models of Huntington’s Disease.38
  • ALA protects brain tissue from lipid peroxidation — a process that contributes to neuron destruction in Alzheimer’s disease.35
  • In mice with ALS (amyotrophic lateral sclerosis), “administration of lipoic acid in the diet produced a significant improvement in survival.”39
ALA for cardiovascular conditions

Oxidative stress is increasingly implicated as a major causative factor in atherosclerosis. It triggers inflammatory events that generate peroxides, superperoxides and hydroxyl radicals within the endothelial tissue of blood vessels. These processes damage the vasculature.2 ALA has been shown to improve endothelial function in the heart arteries of old rats,62 and to “possess a lipid lowering effect… ”63and it “reduced the athero-lesion formation in rabbits fed a high cholesterol diet.”64

Oxidative stress is also highly correlated to hypertension (high blood pressure). In experiments with mice, “the development of hypertension could be either totally prevented or markedly attenuated by chronic treatment with potent antioxidative therapies such as alpha lipoic acid.”42,43

Use with biotin

Since ALA competes with vitamin B7 (biotin) for access to certain enzymes and molecular transporters, it would be sensible to take a biotin supplement if one is supplementing with ALA.65 A dose of a few milligrams of biotin per day should be adequate. The biotin should be taken at a different time than the ALA supplement, since they compete for absorption.


Are Alpha-Lipoic Acid supplements useful for the conditions and purposes mentioned above? We aren’t allowed to tell you, so you should take a look at some of the references cited here, and then decide for yourself.

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