- Thioctic acid
- Lipoic acid
For Patients & Caregivers
Alpha-lipoic acid is an antioxidant. There is no evidence to support its use to treat diseases such as diabetes, HIV, liver disease, or cancer.
Alpha lipoic acid is a compound naturally produced by the body that acts as a cofactor in the production of energy. Laboratory studies show that alpha lipoic acid and its metabolite, dihydrolipoic acid (DHLA), have metal-chelating and free radical-scavenging capacities. In addition, DHLA is able to repair oxidative damage and regenerate antioxidants such as vitamin C, vitamin E, and glutathione. However, when taken orally, the amount of alpha lipoic acid delivered to the body varies. Applying a cream containing Alpha-lipoic acid may help prevent wrinkling of skin due to sun exposure.
- As an antioxidant
Laboratory studies support this use.
- To prevent and treat cancer
Alpha-lipoic acid is an antioxidant. However, there is no evidence that it can be used to treat cancer.
- To relieve conditions related to diabetes, such as diabetic neuropathy
Data from some studies suggest efficacy.
- To treat drug-related toxicity of the auditory nerve
No clinical trials have been performed to evaluate this use.
- To treat HIV and AIDS
No scientific evidence supports this use.
- To treat liver disease
A few studies show that alpha-lipoic acid may prevent nonalcoholic liver disease. More research is needed.
For Healthcare Professionals
Endogenous cofactor found in all eukaryotic and prokaryotic cells that can be obtained in the diet. Patients take this supplement to treat and prevent cancer and to treat diabetes, diabetic neuropathies, HIV/AIDS, and liver disease. Alpha-lipoic acid plays a crucial role in energy production, acts as a potent antioxidant, and exerts apoptotic effects on tumor cells (1) (2) (3).
In human studies, alpha-lipoic acid improved insulin sensitivity, vasodilation, and polyneuropathy in patients with diabetes mellitus (5) (6). Analyses of clinical trials using alpha-lipoic acid showed significant reductions in neuropathic symptoms in diabetic patients (7) (21). Studies have also been conducted to determine its role in reversing neuropathies (8) (9) and liver disease (10) (11), producing mixed results. Findings from another study suggest that topical application of creams containing alpha-lipoic acid may help prevent photoaging of facial skin (12). Furthermore, current data suggest protective effects of antioxidants against Alzheimer’s disease, but a new study failed to find similar effects with a combination of Coenzyme Q, vitamins C, E, and lipoic acid (20).
High doses of alpha-lipoic acid can cause hypoglycemic symptoms (4). In addition, because of its antioxidant effects, alpha-lipoic acid may antagonize the effects of chemotherapy and radiation therapy.
Alpha-lipoic acid acts as a lipophilic free radical scavenger. Dihydrolipoic acid (DHLA), a reduced form of lipoic acid, has more potent antioxidant effects. It can assist in repairing oxidative damage and regenerate endogenous antioxidants such as vitamin C, vitamin E, and glutathione. Both DHLA and lipoic acid also have metal chelating capacities. As a lipoamide, alpha-lipoic acid functions as a cofactor in various multienzyme systems involved in the decarboxylation of alpha-keto acids such as pyruvate (13) (14) (15).
Alpha-lipoic acid was shown to bring about cell cycle arrest in G0/G1 phases in FaDu and Jurkat human tumor cell lines (1). It was also found to scavenge reactive oxygen species in MCF-7 breast cancer cells (16). Reduction of reactive oxygen species was then followed by cancer cell growth arrest and apoptosis (16). In another study, lipoic acid was shown to induce cell death in colorectal cancer cells independent of their p53 status, and to enhance the cytotoxicity of 5-fluorouracil (22).