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.

Insulin and drugs that lower blood sugar -- Apha-lipoic acid can combine with these drugs to further reduce blood sugar levels, resulting in hypoglycemia (low blood sugar). Tell your doctor before taking alpha-lipoic acid and monitor your blood sugar levels closely; your doctor may need to adjust your medication doses.

Thyroid-regulating medications, Levothyroxine -- Apha-lipoic acid may lower levels of thyroid hormone. Blood hormone levels and thyroid function tests should be monitored closely in people taking thyroid hormones who are also taking alpha-lipoic acid.