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Glutathione and L-glutathione are different forms of the same protein. Glutathione is a monomer and contains a single glutathione molecule; l-glutathione is a dimer and contains two.


Glutathione is a protein made from three amino acids: glutamate, cysteine and glycine. It is a powerful antioxidant formed in the liver, and it supports a wide variety of immune functions throughout the body. Glutathione can exist as one of two different forms: glutathione and L-glutathione.


L-glutathione also is known as reduced glutathione, or GSH, and is composed of a single glutathione molecule with the addition of a sulfhydryl group.


When the sulfhydryl groups of two reduced glutathione molecules become oxidized through the loss of electrons, the two molecules can become linked by a disulphide bond and form oxidized glutathione, or GSSG. Oxidized glutathione then is cycled back into reduced glutathione by the glutathione reductase enzyme.


Reduced glutathione is the active form. It donates electrons to free radicals, or molecules with unpaired electrons. The addition of donated electrons neutralizes the free radicals and prevents them from causing cellular damage. Glutathione also participates in various other cellular processes, such as acting as a co-enzyme in biological reactions.