L-Glutamic acid is a nonessential amino acid synthesized naturally by the human body. Characterized by an additional carboxylate group in its side chain, it tends to localize on the surface of proteins. Glutamic acid is often called ‘glutamate’ because, at physiological pH, its carboxylic acid side chain loses a proton and carries a negative charge in its anionic form. Within the body, it plays a vital role in ammonia metabolism, supporting nitrogen balance through its role in detoxifying ammonia. Additionally, it serves as a key neurotransmitter in the nervous system and plays an essential role in protein function and cellular signaling.
Over a century ago, glutamic acid was identified as the key compound responsible for the savory (umami) taste in edible seaweed, which was later recognized as the fifth basic taste along with bitter, sweet, sour, and salty. This discovery led to the development and commercialization of monosodium glutamate (MSG) as a widely used flavor enhancer. At low concentrations, the monosodium salt of glutamic acid imparts a sweet and salty taste, while also enhancing the perception of sour and bitter flavors.
In cosmetics, glutamic acid helps maintain the skin’s pH and also functions as a moisturizer and conditioner. Its unique structure, containing both acidic and basic groups, allows it to bind numerous ions while remaining stable. L-Glutamic acid can be converted into 2-pyrrolidone-5-carboxylic acid (PCA), a compound known for its excellent moisturizing properties. Additionally, studies have reported that glutamic acid may promote hair growth in mice.
