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.
There are 27 conditions associated with numbness or tingling (mouth), numbness or tingling (jaw) and slurred speech. The links below will provide you with more detailed information on these medical conditions from the WebMD Symptom Checker and help provide a better understanding of causes and treatment of these related conditions.