Alpha-lipoic acid is an antioxidant that is made by the body and is found in every cell, where it helps turn glucose into energy. Antioxidants attack “free radicals,” waste products created when the body turns food into energy. Free radicals cause harmful chemical reactions that can damage cells in the body, making it harder for the body to fight off infections. They also damage organs and tissues.
Other antioxidants work only in water (such as vitamin C) or fatty tissues (such as vitamin E), but alpha-lipoic acid is both fat- and water-soluble. That means it can work throughout the body. Antioxidants in the body are used up as they attack free radicals, but evidence suggests alpha-lipoic acid may help regenerate these other antioxidants and make them active again.
1) Peripheral Neuropathy
Peripheral neuropathy can be caused by injury, nutritional deficiencies, chemotherapy or by conditions such as diabetes, Lyme disease, alcoholism, shingles, thyroid disease, and kidney failure. Symptoms can include pain, burning, numbness, tingling, weakness, and itching.
Alpha lipoic acid is thought to work as an antioxidant in both water and fatty tissue, enabling it to enter all parts of the nerve cell and protect it from damage.
Preliminary studies suggest that alpha lipoic acid may help. In one of the largest studies on the use of alpha lipoic acid, 181 people took 600 mg, 1200 mg or 1800 mg of alpha lipoic acid a day or a placebo. After 5 weeks, alpha lipoic acid improved symptoms. The dose that was best tolerated while still providing benefit was 600 mg once daily.
In several studies, alpha-lipoic acid appears to help lower blood sugar levels. Its ability to kill free radicals may help people with diabetic peripheral neuropathy, who have pain, burning, itching, tingling, and numbness in arms and legs from nerve damage.
Taking alpha-lipoic acid may help another diabetes-related condition called autonomic neuropathy, which affects the nerves to internal organs. One study found that 73 people with cardiac autonomic neuropathy, which affects the heart, showed fewer signs of the condition when taking 800 mg of alpha-lipoic acid orally compared to placebo.
2) Brain Function
Alpha lipoic acid can cross the blood-brain barrier, a wall of tiny vessels and structural cells, and pass easily into the brain. It is thought to protect brain and nerve tissue by preventing free radical damage.
3) Age-Related Conditions
As an antioxidant, alpha lipoic acid can neutralize free radicals which can damage cells. Free radical damage is thought to contribute to aging and chronic illness.
Alpha lipoic acid has also been suggested for cataracts, glaucoma, multiple sclerosis, burning mouth syndrome, Alzheimer’s disease and stroke, but large, well-designed studies are needed to see if it’s effective for these conditions.
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a health care provider.
Alpha-lipoic acid hasn’ t been studied in pregnant or breastfeeding women, so researchers don’ t know if it’ s safe.
Side effects are generally rare and may include skin rash.
Alpha-lipoic acid can lower blood sugar levels, so people with diabetes or low blood sugar should take alpha-lipoic acid only under the supervision of their health care provider. (See “Interactions” section.)
Animal studies suggest that people who don’ t get enough thiamine (vitamin B1) should not take alpha-lipoic acid. B1 deficiency is associated with long-term alcohol abuse.
If you are currently being treated with any of the following medications, you should not use alpha-lipoic acid without first talking to your health care provider.
Medications for diabetes — Apha-lipoic acid can combine with these drugs to lower blood sugar levels, raising the risk of hypoglycemia or low blood sugar. Ask your health care provider before taking alpha-lipoic acid, and watch your blood sugar levels closely. Your health care provider may need to adjust your medication doses.
Chemotherapy medications — Alpha lipoic acid may interfere with some chemotherapy medications. Always ask your oncologist before taking any herb or supplement, including alpha lipoic acid.
Thyroid medications, Levothyroxine — Apha-lipoic acid may lower levels of thyroid hormone. Your health care provider should monitor blood hormone levels and thyroid function tests closely.