- Thioctic acid
- Lipoic acid
For Patients & Caregivers
How It Works
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 (ALA) is a compound naturally produced by the body that acts as a cofactor in the production of energy. Laboratory studies show that ALA 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 ALA delivered to the body varies. Applying a cream containing ALA may help prevent wrinkling of skin due to sun exposure.
As an antioxidant
Laboratory studies support this use.
To prevent and treat cancer
ALA is an antioxidant, but 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 HIV and AIDS
No scientific evidence supports this use.
To treat liver disease
A few studies show that ALA may prevent nonalcoholic liver disease. More research is needed.
For Healthcare Professionals
Alpha lipoic acid, also known as ALA, is an endogenous cofactor found in all eukaryotic and prokaryotic cells that can be obtained in the diet. Patients take it in supplement form to treat and prevent cancer and to treat diabetes, diabetic neuropathies, HIV/AIDS, and liver disease. ALA plays a crucial role in energy production, has antioxidant properties, and exerts apoptotic effects on tumor cells (1) (2) (3).
In overweight or obese subjects, ALA supplementation induced mild weight loss and waist circumference reduction (23). ALA improved insulin sensitivity, vasodilation, and polyneuropathy in patients with diabetes mellitus (5) (6). Analyses of clinical trials using ALA showed significant reductions in neuropathic symptoms in diabetic patients (7) (21). Studies to determine its role in reversing neuropathies (8) (9) and liver disease (10) (11) have produced mixed results. Although current data suggest protective effects of antioxidants against Alzheimer’s disease, similar effects were not found with a combination of coenzyme Q, vitamin C, vitamin E, and ALA (20). Topical application with creams containing ALA may help prevent photoaging of facial skin (12).
Preliminary studies suggests supplementation with ALA after carpal tunnel decompression may reduce postsurgical pain (24). In patients with atrial fibrillation (AF), although ALA supplementation significantly reduced serum markers of inflammation, it did not prevent AF recurrence after ablative treatment (25).
High doses of ALA can cause hypoglycemic symptoms (4). In addition, because of its antioxidant effects, ALA may antagonize the effects of chemotherapy and radiation therapy.
Mechanism of Action
ALA acts as a lipophilic free radical scavenger. Dihydrolipoic acid (DHLA), a reduced form of ALA, has more antioxidant effects. It can assist in repairing oxidative damage and regenerate endogenous antioxidants such as vitamin C, vitamin E, and glutathione. Both DHLA and ALA also have metal-chelating capacities. As a lipoamide, ALA functions as a cofactor in various multienzyme systems involved in the decarboxylation of alpha-keto acids such as pyruvate (13) (14) (15).
ALA produced cell cycle arrest in G0/G1 phases in FaDu and Jurkat human tumor cell lines (1). It also scavenged reactive oxygen species (ROS) in MCF-7 breast cancer cells, followed by cell growth arrest and apoptosis (16). In another study, ALA induced cell death in colorectal cancer cells independent of their p53 status, and enhanced cytotoxicity of 5-fluorouracil (22).