- Thioctic acid
- Lipoic acid
For Patients & Caregivers
Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.
How It Works
Alpha-lipoic acid is an antioxidant. Although there is some evidence it may help treat conditions related to diabetes, confirming studies are needed.
Alpha lipoic acid (ALA) is a compound naturally produced by the body that acts as a cofactor in the production of energy. It is often referred to and marketed as a universal antioxidant. Lab studies show that ALA and its metabolite, dihydrolipoic acid (DHLA), have chelating, scavenging, and protective properties. In addition, DHLA is able to repair oxidative damage and regenerate antioxidants such as vitamin C, vitamin E, and glutathione.
Some studies in humans suggest that ALA may help improve liver function, blood sugar levels, and reduce nerve damage caused by diabetes. However, additional studies are needed to confirm safety and effectiveness.
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, but confirming studies are needed.
To treat liver disease
A few studies show that ALA may help improve liver function, but more research is needed.
For Healthcare Professionals
Alpha lipoic acid (ALA) is an endogenous cofactor found in cells that can also be obtained in the diet. It is sometimes referred to as a “universal antioxidant” because it is both water- and fat-soluble and can neutralize reactive oxygen species (26). It is marketed as a dietary supplement for this reason, and is also used as adjuvant therapy for neuropathy and to improve glycemic control. Preclinical studies show that ALA plays a crucial role in energy production, and exerts antioxidant and apoptotic effects (1) (2) (3).
Studies on ALA in humans have been conducted across various populations. Preliminary data suggest long-term supplementation may help preserve walking ability in patients with secondary progressive multiple sclerosis, especially those with less disability at baseline (27). Studies of intravenous and oral forms suggest improved insulin sensitivity, vasodilation, and neuropathy symptoms in diabetic patients (5) (6) (7) (21) (28), although earlier studies to determine its role in reversing neuropathies (8) (9) and liver disease (10) (11) produced mixed results. In women with gestational diabetes, oral ALA may improve liver function and glucose metabolism (29). Meta-analyses also suggest ALA supplementation may reduce inflammatory mediators such as CRP, IL-6, TNF-α, and improve some glucose and lipid parameters (30) (31) (32) (33) (34), but confirming studies are needed.
In other preliminary studies, ALA induced mild weight loss and waist circumference reduction (23) in overweight or obese subjects. It also improved wound healing and scarring in women undergoing cesarean section (35), and reduced postsurgical pain after carpal tunnel decompression (24). In patients with atrial fibrillation, it reduced serum markers of inflammation, but not AF recurrence after ablative treatment (25).
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).
High doses of ALA can cause hypoglycemic symptoms (4), as well as other serious conditions. 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).
In healthy controls and secondary progressive multiple sclerosis patients, ALA appears to stimulate cAMP production (36). In critically ill patients, ALA reduced oxidative stress and improved insulin resistance (37).
Insulin autoimmune syndrome: Spontaneous hypoglycemia in a woman who began ALA supplementation for joint pain (38). This syndrome has been associated with some HLA alleles, one of which was identified in this patient. Overall about 27 such cases have been reported, mostly in Japan with additional reports from Italy (39).
Multiple organ failure: In a 70-year-old woman, due in part to a prescribing error that led to an inappropriately high dose of ALA (40).
Pediatric convulsions: Caused by accidental access by a toddler to alpha lipoic acid (41). Adults may view ALA as just a supplement, but inadvertent access by children leading to accidental ingestion can cause intoxication, convulsions, and other serious conditions.