Alpha-lipoic acid is an antioxidant made by the body. It is found in every cell, where it helps turn glucose into energy. Antioxidants attack "free radicals," waste products created when the body turns food into energy. Free radicals cause harmful chemical reactions that can damage cells, making it harder for the body to fight off infections. They also damage organs and tissues.
Other antioxidants work only in water (such as vitamin C) or fatty tissues (such as vitamin E). But alpha-lipoic acid is both fat and water soluble. That means it can work throughout the body. Antioxidants in the body are used up as they attack free radicals. But evidence suggests alpha-lipoic acid may help regenerate these other antioxidants and make them active again.
In the cells of the body, alpha-lipoic acid is changed into dihydrolipoic acid. Alpha-lipoic acid is not the same as alpha linolenic acid, which is an omega-3 fatty acid that may help heart health. There is confusion between alpha-lipoic acid and alpa linolenic acid because both are sometimes abbreviated ALA. Alpha-lipoic acid is also sometimes called lipoic acid.
Several studies suggest alpha-lipoic acid helps lower blood sugar levels. Its ability to kill free radicals may help people with diabetic peripheral neuropathy, who have pain, burning, itching, tingling, and numbness in arms and legs from nerve damage. Researchers believe Alpha-lipoic acid helps improve insulin sensitivity.
Alpha-lipoic acid has been used for years to treat peripheral neuropathy in Germany. However, most of the studies that have found it helps have used intravenous (IV) alpha-lipoic acid. It's not clear whether taking alpha-lipoic acid by mouth will help. Most studies of oral alpha-lipoic acid have been small and poorly designed. One study did find that taking alpha-lipoic acid for diabetic neuropathy reduced symptoms compared to placebo.
Taking alpha-lipoic acid may help another diabetes-related condition called autonomic neuropathy, which affects the nerves to internal organs. One study of 73 people with cardiac autonomic neuropathy, which affects the heart, found that subjects reported fewer signs of the condition when taking 800 mg of alpha-lipoic acid orally compared to placebo.
Brain Function and Stroke
Because alpha-lipoic acid can pass easily into the brain, it may help protect the brain and nerve tissue. Researchers are investigating it as a potential treatment for stroke and other brain problems involving free radical damage, such as dementia. So far, there's no evidence to say whether or not it works.
Preliminary studies suggest alpha-lipoic acid may help treat glaucoma. But there is not enough evidence to say for sure whether it works. In one study on aging skin, a cream with 5% lipoic acid helped reduce fine lines from sun damage. Studies show ALA binds with toxic metals, such as mercury, arsenic, iron, and other metals that act as free radicals. Preliminary studies also suggest that ALA may play a role in managing other conditions including erectile dysfunction and cancer. And preliminary studies suggest it may reduce complications associated with otitis media (ear infections).
If you are healthy, your body makes enough alpha-lipoic acid. It is also found in red meat, organ meats (such as liver), and yeast -- particularly brewer's yeast.
Alpha-lipoic acid supplements are available as capsules. Your health care provider can also give it by injection.
How to Take It
Alpha-lipoic acid has not been studied in children, so it is not recommended for pediatric use.
Check with your doctor regarding dosing recommendations. Studies are mixed about whether or not to take ALA with meals.
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a health care provider.
Alpha-lipoic acid hasn't been studied in pregnant or breastfeeding women, so researchers don't know if it's safe.
Side effects are generally rare and may include insomnia, fatigue, diarrhea, and skin rash.
Alpha-lipoic acid can lower blood sugar levels, so people with diabetes or low blood sugar should take alpha-lipoic acid only under the supervision of their health care provider.
Animal studies suggest that people who don't get enough thiamine (vitamin B1) should not take alpha-lipoic acid. B1 deficiency is associated with long-term alcohol abuse.
If you are being treated with any of the following medications, you should not use alpha-lipoic acid without first talking to your health care provider.
Medications for diabetes
Apha-lipoic acid can combine with these drugs to lower blood sugar levels, raising the risk of hypoglycemia or low blood sugar. Ask your provider before taking alpha-lipoic acid, and watch your blood sugar levels closely. Your provider may need to adjust your medication doses.
Alpha-lipoic acid may interfere with some chemotherapy medications. Always ask your oncologist before taking any herb or supplement, including alpha-lipoic acid.
Thyroid medications, Levothyroxine
Apha-lipoic acid may lower levels of thyroid hormone. Your provider should monitor blood hormone levels and thyroid function tests closely.
Vitamin B1 (Thiamine)
Alpha lipoic acid can lower the level of vitamin B1 (Thiamine) in the body. This can be particularly dangerous in alcoholics where malnutrition is often already present.
Androne L, Gavan NA, Veresiu IA, Orasan R. In vivo effect of lipoic acid on lipid peroxidation in patients with diabetic neuropathy. In Vivo. 2000;14(2):327-330.
Beitner H. Randomized, placebo controlled, double-blind study on the clinical efficacy of a cream containing 5% alpha-lipoic acid related to photoaging of facial skin. Br J Dermatol. 2003;149(4):841-849.
Berkson BM. A conservative triple antioxidant approach to the treatment of hepatitis C. Combination of alpha lipoic acid (thioctic acid), silymarin, and selenium: three case histories. Med Klin. 1999;94 Suppl 3:84-89.
Clark WM, Rinker LG, Lessov NS, Lowery SL, Cipolla MJ. Efficacy of antioxidant therapies in transient focal ischemia in mice. Stroke. 2001;32(4):1000-1004.
Faust A, Burkart V, Ulrich H, et al. Effect of lipoic acid on cyclophosphamide-induced diabetes and insulitis in non-obese diabetic mice. Int J Immunopharmacol. 1994;16(1):61-66.
Head KA. Natural therapies for ocular disorders, part two: cataracts and glaucoma. Altern Med Rev. 2001;6(2):141-166.
Hruby K, Csomos G, Fuhrmann M, Thaler H. Chemotherapy of Amanita phalloides poisoning with intravenous silibinin. Hum Exp Toxicol. 1983;2(2):183-195.
Ibrahimpasic K. Alpha lipoic acid and glycaemic control in diabetic neuropathies at type 2 diabetes treatment. Med Arh. 2013;67(1):7-9.
Lynch MA. Lipoic acid confers protection against oxidative injury in non-neuronal and neuronal tissue. Nutr Neurosci. 2001;4(6):419-438.
Melhem MF, Craven PA, Derubertis FR. Effects of dietary supplementation of alpha-lipoic acid on early glomerular injury in diabetes mellitus. J Am Soc Nephrol. 2001;12(1):124-133.
Melhem MF, Craven PA, Liachenko J, et al. Alpha-lipoic acid attenuates hyperglycemia and prevents glomerular mesangial matrix expansion in diabetes. J Am Soc Nephrol. 2002;13(1):108-116.
Melmed S, Polonsky KS, Larsen PR, Kronenberg HM. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier; 2016.
Mitkov MD, Aleksandrova IY, Orbetzova MM. Effect of transdermal testosterone or alpha-lipoic acid on erectile dysfunction and quality of life in patients with type 2 diabetes mellitus. Folia Med (Plovdiv). 2013;55(1):55-63.
Monograph:Alpha-Lipoic Acid. Altern Med Rev. 2006;11(3):232-237.
Nagamatsu M, Nickander KK, Schmelzer JD, et al. Lipoic acid improves nerve blood flow, reduces oxidative stress, and improves distal nerve conduction in experimental diabetic neuropathy. Diabetes Care. 1995;18(8):1160-1167.
Packer L, Kraemer K, Rimbach G. Molecular aspects of lipoic acid in the prevention of diabetes complications. Nutrition. 2001;17(10):888-895.
Packer L, Tritschler HJ, Wessel K. Neuroprotection by the metabolic antioxidant alpha-linoic acis. Free Radic Biol Med. 1997;22(1-2):359-378.
Packer L, Witt EH, Tritschler HJ. Alpha-lipoic acid as a biological antioxidant. Free Rad Bio Med. 1995;19(2):227-250.
Panigrahi M, Sadguna Y, Shivakumar BR, et al. Alpha-Lipoic acid protects against reperfusion injury following cerebral ischemia in rats. Brain Res. 1996;717(1-2):184-188.
Rakel D. Rakel Integrative Medicine. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2012.
Segermann J, Hotze A, Ulrich H, et al. Effect of alpha-lipoic acid on the peripheral conversion of thyroxine to triiodothyronine and on serum lipid-, protein- and glucose levels. Arzneimittelforschung. 1991;41(12):1294-1298.
Tatar A, Korkmaz M, Yayla M, et al. Anti-inflammatory and anti-oxidative effects of alpha-lipoic acid in experimentally induced acute otitis media. J Laryngol Otol. 2016;130(7):616-623.
Xu J, Gao H, Song L, et al. Flaxseed oil and alpha-lipoic acid combination ameliorates hepatic oxidative stress and lipid accumulation in comparison to lard. Lipids Health Dis. 2013;12:58.
Yoo TH, Lee JH, Chun HS, Chi SG. a-Lipoic acid prevents p53 degradation in colon cancer cells by blocking NF-kB induction of RPS6KA4. Anticancer Drugs. 2013;24(6):555-565.
Ziegler D, Ametov A, Barinov A, et al. Oral treatment with alpha-lipoic acid improves symptomatic diabetic polyneuropathy: The SYDNEY 2 trial. Diabetes Care. 2006;29(11):2365-2370.
Ziegler D, Gries FA. Alpha-lipoic acid in the treatment of diabetic peripheral and cardiac autonomic neuropathy. Diabetes. 1997;46 (suppl 2):S62-66.
Ziegler D, Reljanovic M, Mehnert H, Gries FA. Alpha-lipoic acid in the treatment of diabetic polyneuropathy in Germany: current evidence from clinical trials. Exp Clin Endocrinol Diabetes. 1999;107(7):421-430.
Dihydrolipoic acid; Lipoic acid; Lipolate; Thiotic acid
- Last reviewed on 1/1/2017
- Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M Editorial team.
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