Alpha-lipoic acid is being recognized for its great value as an antioxidant, which means it neutralizes naturally occurring, but harmful, chemicals known as free radicals. Alpha-lipoic acid is relatively unique because it works in both the aqueous (water soluble) and lipid (fat soluble) phases of the body. One of the more interesting findings about alpha-lipoic acid is that it may help regenerate other antioxidants that have been used up. Some research also suggests that lipoic acid may do the work of other antioxidants in which the body is deficient.^3,4

Natural Sources: The body generally makes enough alpha-lipoic acid to supply it’s needs; however, certain conditions such as diabetes, liver cirrhosis, and heart disease are accompanied by low levels of alpha -lipoic acid,¹ and supplementation may be helpful. Liver and yeast contain some alpha-lipoic acid.

Useful in the treatment of: Diabetic Neuropathy:Alpha-lipoic acid has been widely used in Germany to treat the nerve damage caused by diabetes, called diabetic neuropathy. Symptoms include numbness, pain, and burning, mostly in the hands and feet (so-called "stocking and glove" distribution). There is clear evidence that it has benefit intravenously ^5-7, and some studies also show a benefit with the oral form also. ^7-9

Glucose control in Diabetes: There are some studies suggesting that diabetic control may be improved with alpha-lipoic acid, but the evidence is mixed. ^10-14

Liver disease: One small study has shown benefit for alpha-lipoic acid as part of a combination "triple antioxidant" therapy for hepatitis C with liver failure. ¹⁵

Lead toxicity: Alpha-lipoic acid seems to be a good candidate for therapeutic intervention of lead poisoning, in combination with a chelator. ¹⁶

Dosage: As a general antioxidant, 50 mg per day is generally considered sufficient. For treatment of diabetic neuropathy or for liver disease, 300 mg twice daily is an appropriate dose.

Precautions/Contraindications: It is generally thought to be without side effects. Safety in pregnant and lactacting women, as well as children has not been established

References:

¹Kagan VE, Shvedova A, Serbinova E, et al. Dihydrolipoic acid—a universal antioxidant both in the membrane and in the aqueous phase. Reduction of peroxyl, ascorbyl, and chromanoxyl radicals. Biochem Pharmacol. 1992;44:1637–1649.
²Matsugo S, Yan LJ, Han D, et al. Elucidation of antioxidant activity of alpha-lipoic acid toward hydroxyl radical. Biochem Biophys Res Commun. 1995;208:161–167.
³Packer L, Witt EH, Tritschler HJ. Alpha–lipoic acid as a biological antioxidant. Free Radic Biol Med. 1995;19:227–250.
⁴Podda M, Tritschler HJ, Ulrich H, et al. Alpha–lipoic acid supplementation prevents symptoms of vitamin E deficiency. Biochem Biophys Res Commun. 1994;204:98–104.
⁵Ziegler D, Hanefeld M, Ruhnau KJ, et al. The ALADIN III Study Group. Treatment of symptomatic diabetic polyneuropathy with the antioxidant alpha-lipoic acid: a 7-month multicenter randomized controlled trial (ALADIN III Study). Diabetes Care. 1999;22:1296–1301.
⁶Ziegler D, Hanefeld M, Ruhnau KJ, et al. Treatment of symptomatic diabetic peripheral neuropathy with the anti-oxidant alpha-lipoic acid. A 3-week multicentre randomized controlled trial (ALADIN Study). Diabetologia. 1995;38:1425–1433.
⁷Ziegler D, Gries FA. Alpha-lipoic acid in the treatment of diabetic peripheral and cardiac autonomic neuropathy. Diabetes. 1997;46(suppl 2):S62–S66.
⁸Kahler W, Kuklinski B, Ruhlmann C, et al. Diabetes mellitus—a free radical–associated disease. Results of adjuvant antioxidant supplementation [in German; English abstract]. Z Gesamte Inn Med. 1993;48:223–232.
⁹Ruhnau KJ, Meissnert HP, Finn JR, et al. Effects of 3-week oral treatment with the antioxidant thioctic acid (alpha-lipoic acid) in symptomatic diabetic polyneuropathy. Diabet Med. 1999;16:1040–1043.
¹⁰Jacob S, Henriksen EJ, Schiemann AL, et al. Enhancement of glucose disposal in patients with type 2 diabetes by alpha–lipoic acid. Arzneimittelforschung. 1995;45:872–874.
¹¹Kawabata T, Packer L. Alpha-lipoate can protect against glycation of serum albumin, but not low density lipoprotein. Biochem Biophys Res Commun. 1994;203:99–104.
¹²Nagamatsu 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;18:1160–1167.
¹³Suzuki YJ, Tsuchiya M, Packer L. Lipoate prevents glucose-induced protein modifications. Free Radic Res Commun. 1992;17:211–217.
¹⁴Jacob S, Ruus P, Hermann R, et al. Oral administration of RAC-alpha-lipoic acid modulates insulin sensitivity in patients with type-2 diabetes mellitus: a placebo-controlled pilot trial. Free Radic Biol Med. 1999;27:309–314.
¹⁵Berkson 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 Oct, 94 Suppl 3:, 84-9
¹⁶Packer L. Antioxidant role of alpha-lipoic acid in lead toxicity. Free Radic Biol Med, 1999 Jul, 27:1-2, 75-81