The most frequently seen major side effect of alpha-lipoic acid is low blood sugar, according to WebMD. Both the National Institutes of Health and WebMD list alpha-lipoic acid as "possibly safe" in moderate doses when taken orally, intravenously or topically. Other major side effects include thiamine, or vitamin B1, deficiency and interference with thyroid medications. Minor but common side effects include a skin rash and nausea, states Drugs.com.Continue Reading
As of 2009, the National Institutes of Health notes that is no safely defined upper limit for alpha-lipoic acid supplementation in humans. However, the administration of large doses for treatment of the diabetic disorders retinopathy and neuorpathy have been approved in Germany for more than 50 years. One clinical trial showed no major adverse side effects when participants were given oral doses of 1,800 milligrams per day over a six-month period.
WebMD and Drugs.com both report the most common, but minor, side effects of alpha-lipoic acid use are skin rash and nausea. Low blood sugar and thiamine deficiency are the next most common side effects, but are more severe. Special precautions when using alpha-lipoic acid should be taken by diabetics, as well as by those with thyroid disorders and those who consume large amounts of alcohol. This is because alpha-lipoic acid can interfere with some medications and exacerbate the body's loss of vitamin B1, which is frequently seen in people with excessive alcohol consumption.
Women who are pregnant or nursing should avoid taking alpha-lipoic acid, states WebMD, as no studies have been conducted about possible side effects under these conditions. It is important to consult a health care professional before making changes to vitamin or supplement intake. Side effects of any medication, supplement or vitamin can be reported to the Food and Drug Administration.Learn more about Side Effects