What are the possible side effects of alpha-lipoic acid?

Possible side effects of alpha-lipoic acid include drowsiness, blurred vision, sweating and hunger. Other possible side effects include weakness, headache, a fast heart rate, and feeling close to fainting. Some people may experience irritability, nausea, tremors or tiredness, according to Drugs.com.

Confusion or have trouble concentrating may occur when taking alpha-lipoic acid. Other possible side effects include numbness or tingling, dizziness, muscle cramps and mild skin rash. Signs of an allergic reaction to alpha-lipoic acid include difficulty breathing, hives and swelling of the throat, lips, face or tongue, states Drugs.com.

Because alpha-lipoic acid may lower blood sugar levels, people with diabetes and other related conditions should watch their blood sugar levels carefully when taking it. The effects of alpha-lipoic acid on pregnant or nursing women is unknown, as of 2015. For this reason, pregnant or nursing women should avoid alpha-lipoic acid to be safe, notes WebMD.

Serious health risks are associated with taking alpha-lipoic acid with a thiamine deficiency. People with low thiamine levels should take a supplement. People who drink alcohol regularly should take a thiamine supplement when taking alpha-lipoic acid. Alpha-lipoic acid may interfere with over or under-active thyroid treatments, according to WebMD. Chemotherapy agents may be less effective in people who use alpha-lipoic acid.