Burning mouth syndrome (BMS) is a poorly understood condition in which a person experiences ongoing moderate to severe pain in the tongue and/or mouth. Although the cause of BMS remains unclear, some patterns have become clear to researchers. The pain is generally worst in the late afternoon and early evening, but disappears at night. Most often, more than one part of the mouth is involved. Common areas of burning pain include the tongue, the hard palate (the front part of the roof of the mouth), and the lower lip. Many people recover spontaneously within six or seven years. Dry mouth and altered taste sensations often, but not always, accompany the pain.

BMS is thought to fall in the general category of “neuropathic pain,” meaning that it probably results from altered nerve function, possibly in the nerves carrying taste sensation. Use of drugs in the ACE inhibitor family has been implicated in some cases of burning mouth syndrome, but the reason for this apparent connection remains unclear.

Conventional treatment for BMS consists of drugs used to treat neuropathic pain in general, including anticonvulsants, sedatives in the benzodiazepine family, and tricyclic antidepressants. There is inadequate research at present to determine the precise efficacy of these treatments.

The supplement lipoic acid has shown promise for the treatment of diabetic neuropathy, another form of neuropathic pain. Lipoic acid has also been studied for burning mouth syndrome with mixed results.5

In a double-blind trial, 60 people with burning mouth syndrome received either lipoic acid (200 mg 3 times daily) or placebo for a period of months.1Researchers reported that almost all people receiving lipoic acid showed significant improvement, while none of those taking placebo improved, and relative benefits endured at 12-month follow-up. The total lack of benefit seen in the placebo group is difficult to believe, and raises concerns about the study’s reliability. Subsequently, two double-blind trials involving 52 and 39 patients respectively failed to find any benefit for lipoic acid and noted quite a large placebo response.5,6

For more information, including dosage and safety issues, see the full Lipoic Acid article.