GABA Side Effects. While GABA is a safe, natural substance, it is not without its side effects. Common side effects include a shortness of breath, coupled with throbbing sensations in the chest, and a possible itching or tingling sensation in the face, neck, and limbs. While both sets of symptoms are alarming at first, they are safe and are not Clinical studies suggest that taking up to 120 milligrams (mg) of GABA per day as supplements for 12 weeks is unlikely to cause adverse effects. People should take care when using them with other drugs. Using them with medications for high blood pressure or epilepsy may increase the impact of those drugs. .

do gaba supplements increase gaba