No toxicity has been reported with supplements up to 600 mg for every kg of body weight. Minor side effects that may occur with supplementation (but are unusual) include a burning sensation in the mouth, loss of appetite, nausea and diarrhoea.
1. Hyperventilation. Hyperventilation is one of the causes of numbness in lips, which is caused due to anxiety and stress. When a person is hyperventilating he inhales and exhales in rapid succession, thus causing a shortage of carbon dioxide in his blood. This loss further results in more anxiety.
A common symptom of dry mouth is a tingling sensation in the tongue. Dry mouth can be caused by certain illnesses and some medications. Talk to your doctor if you are concerned about dry mouth symptoms. Numbness and tingling in the lips and tongue can sometimes be a side effect of a drug. Call your doctor if you experience these symptoms while taking medication. Itchiness and tingling in the lips and tongue are common symptoms of a food allergy. If you think you might have a food allergy, talk to your doctor about testing. People with diabetes can get numbness and tingling in the lips and tongue if their blood sugar drops too low (hypoglycemia).