MSG is very safe in normal quantities with a similar safety profile to salt. You can drink MSG water to kill yourself but it’d be like drinking a gallon of seawater. It’s monosodium glutamate. Monosodium as in NaCl (table salt) and glutamate as in the amino acid and neurotransmitter. Once they disassociate in water, they’re both some of the most basic molecules used by all life, including for protein production.