- 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.
What is it?
Alpha-lipoic acid is a chemical your body makes. It’s also found in foods such as red meat, spinach, broccoli, tomatoes, peas, Brussel sprouts, and rice bran.
You can take alpha-lipoic acid as a dietary supplement. It comes as tablets or capsules.
What are the potential uses and benefits?
Your body uses alpha-lipoic acid to make energy. Alpha-lipoic acid is also used to:
- Treat nerve pain due to diabetes
- Treat liver disease
Alpha-lipoic acid has other uses, but doctors haven’t studied them to see if they work.
It’s generally safe to eat foods that have alpha-lipoic acid. Talk with your healthcare providers before taking alpha-lipoic acid supplements. Supplements are stronger than compounds that are naturally found in foods. They can also interact with some medications and affect how they work. For more information, read the “What else do I need to know?” section below.
What are the side effects?
Side effects of using alpha-lipoic acid may include:
- Nausea (feeling like you’re going to throw up)
- Vomiting (throwing up)
- Low blood sugar level
What else do I need to know?
- Talk with your healthcare provider if you take drugs that lower your blood sugar level. If you do, alpha-lipoic acid may be harmful because it also lowers your blood sugar level.
For Healthcare Professionals
Alpha lipoic acid (ALA) is an endogenous cofactor found in cells. It can be obtained from a variety of foods in the diet. ALA is sometimes referred to as a “universal antioxidant” because it is both water- and fat-soluble and can neutralize free radicals (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. Data from a double-blind RCT suggest short-term ALA supplementation can be beneficial for idiopathic pain without altering glycemia in patients with normal levels (45), but another trial did not find it helpful for fibromyalgia (46).
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 in overweight or obese subjects (23). Long-term use of R-ALA, which has increased bioavailability, produced modest weight loss in overweight/obese adults without significant reductions in triglyceride levels (47).
In postoperative settings, ALA helped improve wound healing and scarring in women undergoing cesarean section (35), and reduced 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, such effects were not found with a combination of coenzyme Q, vitamin C, vitamin E, and ALA (20). And even though preclinical studies of ALA demonstrate antioxidant properties with efficacy in neurodegenerative models, oral ALA was ineffective in patients with geographic atrophy from advanced macular degeneration (48).
High doses of ALA can cause hypoglycemic symptoms (4) and other serious conditions. ALA may also antagonize the effects of chemotherapy and radiation therapy because of its antioxidant properties.
Organ meats, spinach, broccoli, tomato, peas, Brussels sprouts, rice bran
Purported Uses and Benefits
- Liver disease
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 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 (IAS): 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).
IAS misdiagnosed as an insulinoma: In a 71-year-old female who had a pancreatic cystic lesion, but was also prescribed ALA 600 mg/day for osteoarthritis, about 1 week before the appearance of symptoms (50).
Recurrent hypoglycemia from IAS: In a 36-year-old Indian male with dizziness and feeling of hunger with sweating, related to ALA supplement use and requiring steroid therapy (51).
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.
Peditriatric intoxication, poisoning: Several cases, including one case in a teenage girl who presented with seizures and coagulopathy after low-dose ALA of about 30 mg/kg (52).