Food grade and pharmaceutical grade are classified by product application or specific application field to identify quality levels, not purity grade. Food grade product and pharmaceutical grade product acid are used as medicine and food, respectively. Pharmaceutical grade GABA is used in the treatment of diseases and allowed to have certain side effects. However, Food grade GABA is used to provide nutrition, and cannot have any acute, sub-acute and chronic side effects. The distinction between the two is not the difference of purity, but the differences of their processing techniques and impurities. In terms of harmful impurities, Food grade GABA is made of L-glutamate as raw material by fermentation of lactic acid bacteria, which is based on food bulletins. It does not contain chemical toxic raw materials-2-pyrrolidone, so it is edible. Pharmaceutical grade GABA is synthesized chemically with 2-pyrrolidone as substrate, belonging to pharmaceutical ingredients. Although its purity is greater than 99%, 2-pyrrolidinone residue in product is not required quantitatively. At present, the forms of GABA (g-aminobutyric acid) in clinical use are GABA sodium chloride injection and GABA pill. The species had not been listed in United States and European Pharmacopoeia. Although the domestic drug standard of GABA contains several quality items, it does not satisfy 2-pyrrolidone testing. In one word, pharmaceutical grade GABA cannot be used in food.

Let’s take a simple example of alcohol. Alcohol is the main ingredient in the alcohol beverages, such as beer, wine, rice wine, low degree alcohol liquor. These beverages are made of barlay, grape, rice, wheat, sorghum, peas et al. as raw materials, respectively. Their alcohol concentrations or contents are relatively low, generally 3~40%, but they're edible. However, for industrial grade pure alcohol, its raw material is fossil oil or stale starch. Although the alcohol content of industrial alcohol is more than 70%, the contents of methanol and lead in industrial alcohol are more than them of food standards, and  it is not edible. It can't even be used to flavor liquor as a kind of spice.