Monosodium Glutamate
Properties
| State | Solid at room temperature |
| Color | White crystalline powder |
| Solubility | Soluble in water (74 g/100 mL at 20 °C) |
| Melting Point | 232 °C (decomposes) |
About Monosodium Glutamate
MSG is the sodium salt of L-glutamic acid (formula C5H8NNaO4, molar mass 169.111 g/mol) and the molecule that defines umami — the savory fifth taste that Kikunae Ikeda isolated from a kombu dashi broth in 1908 and patented as a flavor enhancer the same year. The compound stimulates the T1R1/T1R3 heterodimer receptor on taste cells, producing the brothy, mouth-filling sensation that makes a parmesan rind, an aged soy sauce, or a long-cooked tomato sauce taste like more than the sum of its parts. Glutamate is also the principal excitatory neurotransmitter in the human brain, but the dietary form does not cross the blood-brain barrier in any meaningful quantity — the gut metabolizes essentially all ingested glutamate before it reaches systemic circulation. Industrial production runs at over 3 million tonnes per year, almost entirely by aerobic fermentation of cane or corn sugars with engineered Corynebacterium glutamicum strains; the same fermentation route now also produces L-lysine and L-threonine for animal feed. The persistent "Chinese restaurant syndrome" claim has been investigated in dozens of double-blind crossover trials since the 1970s, and no consistent dose-response or symptom cluster has been reproducible — the FDA, EFSA, and JECFA all classify MSG as GRAS at typical dietary intakes.
Where you'll encounter it
If you've ever wondered why a tomato slow-roasted for two hours tastes so much more savory than a raw one, the answer is glutamate. The protein in the tomato breaks down into free amino acids during cooking, and free glutamate concentration goes from a few milligrams per 100 g to several hundred — the same effect that makes parmesan, miso, and dry-aged steak so flavorful. Restaurant cooks have learned to add MSG by name: David Chang at Momofuku has talked about it openly, and any working line cook in a ramen shop is shaking it into the tare. In a sensory-science lab, MSG dissolved at 0.5% in water is the standard reference solution for training tasters to recognize umami, the way 0.05% caffeine trains them on bitterness. Home cooks have started keeping a shaker of it next to the salt for the same reason.
Common Uses
- Umami flavor enhancer in restaurant kitchens and home cooking
- Standard 0.5% reference solution for sensory-science taster training
- Sodium-reduction tool in processed foods (delivers savor at lower Na)
- Seasoning ingredient in instant ramen, snack chips, and bouillon cubes
- Glutamate source in clinical nutrition formulas for taste palatability
- Bench reagent for taste-receptor T1R1/T1R3 binding assays in sensory research
Safety Information
GRAS-classified by the FDA since 1958, with the same status from EFSA, JECFA, and Health Canada. The 1995 FASEB review for the FDA examined every controlled trial through that date and found no reproducible adverse effect at normal dietary doses; the 2017 EFSA reassessment set an ADI of 30 mg/kg body weight per day, well above typical intakes (a heavily seasoned restaurant meal contains around 0.5 g, or about 7 mg/kg for a 70 kg adult). A small fraction of subjects in blinded high-dose challenges (over 3 g on an empty stomach) report transient headache or flushing, but the effect does not reproduce when MSG is consumed with food. Sodium content is roughly one-third that of NaCl by mass, which is why processed-food formulators use it as a sodium-reduction strategy.
This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.